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  • 1. Czigler, Peter E.
    et al.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Department of language studies.
    Poussa, Patricia
    Umeå University, Faculty of Arts, Department of language studies.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Department of language studies.
    Language learning through fuzzy ears: one cause of identity loss? Some preliminary thoughts from an experimental case study2008In: Tidskrift för lärarutbildning och forskning / Journal of Research in Teacher Education., ISSN 14047659, Vol. 15, no 2, p. 23-37Article in journal (Refereed)
  • 2.
    Doorn, Jan van
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Arts, Department of language studies.
    Influence of speech task and utterance length on the measurement of pitch variability in the speech of Parkinson's disease patients after deep brain stimulation2013Conference paper (Other academic)
    Abstract [en]

    Parkinson’s disease (PD) affects patients voice characteristics, reducing pitch variability compared to normal controls (1,2). Previous reports have shown an increase in pitch variability due to deep brain stimulation (DBS) of the Subthalamic nucleus (STN) (3). For patients stimulated in caudal zona incerta (cZi), the results indicate no effect on pitch variability in a read speech task{Karlsson:2012jr}.

    The present study aimed at investigating the effects of speech task (spontaneous or read speech) and the lenght of the utterance on overall measures of pitch variability observed in DBS-treated patients. Ten patients treated with STN-DBS and ten patients treated with cZi-DBS were included in this prospective study.

    Utterances produced sponatenously and produced during readings of a standard passage were compared in terms of treatment effects in pitch variability due to STN-DBS and cZi-DBS (Stim OFF and Stim ON recordings made 1,5 hour apart, all in Med ON) 6 and 12 months after operation. The results indicate that pitch variability is affected differently by STN-DBS and cZi-DBS depending on speech task and utterance length. In short utterances (<10 words), an increase in pitch variability is observed for both treatment groups and both speech tasks. For longer utterances, however, a more diverse effect of treatment and speech task is observed. The results therefore suggest that spech task and characteristics of thate utterance should be carefully considered when drawing conclusions on the overall effect of DBS on pitch variability.

    1. Jiménez-Jiménez FJ, Gamboa J, Nieto A, Guerrero J, Ortí-Pareja M, Molina JA, et al. Acoustic voice analysis in untreated patients with Parkinson's disease. Parkinsonism Relat. Disord. 1997 Apr;3(2):111–6. 

    2. Holmes RJ, Oates JM, Phyland DJ, Hughes AJ. Voice characteristics in the progression of Parkinson’s disease. International Journal of Language & Communication Disorders. 2000;35(3):407–18. 

    3. Dromey C, Kumar R, Lang AE, Lozano AM. An investigation of the effects of subthalamic nucleus stimulation on acoustic measures of voice. Mov. Disord. 2000;15(6):1132–8.

  • 3.
    Eklund, Elisabeth
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Qvist, Johanna
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Sandström, Lena
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Viklund, Fanny
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Arts, Department of language studies.
    Perceived articulatory precision in patients with Parkinson’s disease after deep brain stimulation of subthalamic nucleus and caudal zona incerta2015In: Clinical Linguistics & Phonetics, ISSN 0269-9206, E-ISSN 1464-5076, Vol. 29, no 2, p. 150-166Article in journal (Refereed)
    Abstract [en]

    The effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and caudal zona incerta (cZi) on speech articulation in patients with Parkinson’s disease (PD) was investigated. Read speech samples were collected from nine patients with STN-DBS and ten with cZi-DBS. The recordings were made preoperatively and 12 months postoperatively with stimulator on and off (on medication). Blinded, randomized, repeated perceptual assessments were performed on words and isolated fricatives extracted from the recordings to assess 1) overall articulatory quality ratings, 2) frequency of occurrence of misarticulation patterns, and 3) fricative production. Statistically significant worsening of articulatory measures on- compared with off-stimulation occurred in the cZi-DBS group, with deteriorated articulatory precision ratings, increased presence of misarticulations (predominately altered realizations of plosives and fricatives) and a reduced accuracy in fricative production. A similar, but not significant, trend was found for the STN-DBS group. 

  • 4.
    Hägglund, Patricia
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Sandström, Linda
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Voice Tremor in Patients With Essential Tremor: Effects of Deep Brain Stimulation of Caudal Zona Incerta2016In: Journal of Voice, ISSN 0892-1997, E-ISSN 1873-4588, Vol. 30, no 2, p. 228-233Article in journal (Refereed)
    Abstract [en]

    Objectives. The present study aimed at evaluating the effect of deep brain stimulation (DBS) of the caudal zona incerta (cZi) on voice tremor in patients with essential tremor (ET). Study Design. This is a prospective nonrandomized design with consecutive patients.

    Methods. Twenty-six patients operated with cZi DBS were evaluated under two conditions: without stimulation (Stim OFF) and with stimulation (Stim ON). Voice tremor was assessed on the basis of recordings of sustained vowel productions using a four-point rating scale in a blinded and randomized procedure. Averaged values of multiple assessments for each stimulus were used in statistical testing. The group of patients with voice tremor in Stim OFF was analyzed separately from the group of patients without voice tremor.

    Results. Voice tremor was significantly reduced on stimulation compared with off for the subgroup with initial voice tremor. Voice tremor prevalence was found to be 50% (13 patients). Individual differences in voice tremor outcome were noticeable. Six of the patients with voice tremor at baseline improved substantially by cZi DBS treatment.

    Conclusions. On the group level, voice tremor in patients with ET was found to reduce when stimulating the cZi. Bilateral stimulation was indicated to be more effective in reducing voice tremor than unilateral stimulation. However, individual voice tremor outcomes suggest that not all patients benefit from cZi DBS. Severity of voice tremor at baseline may not be a good predictor of voice tremor outcome after cZi DBS. Patients should be informed before surgery regarding individual differences in response to DBS treatment.

  • 5.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Are homonyms in consonant cluster productions caused by articulatory or perceptual processes: A discussion based on one child's development2003In: Proceedings from FONETIK 2003, 2003, p. 73-76Conference paper (Other academic)
  • 6.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Development of adult-like place and manner of articulation in initial sC clusters2005In: Proceedings FONETIK 2005: XVIIIth Swedish Phonetics Conference, 2005, p. 71-74Conference paper (Other academic)
    Abstract [en]

    Previous investigations have proposed that nasality in consonants are more perceptually stable than place of articulation inconstrained conditions. This paper investigates the progression of initial consonant clusters from a reduced to an adult-like form in terms of manner and place of articulation in the speech of children between the age of 1;6 and 3;5. The results show an earlier onset of stable production of manner compared to place for in both full clusters and in the reduced form. The results are interpreted as evidence of the importance of perceptual salience of segmental properties in the acquisition initial consonant clusters.

  • 7.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Development of Complex Syllable Onsets: Evidence from duration measurements2004In: Proceedings from the XVIIth Swedish Phonetics Conference, 2004, p. 100-103Conference paper (Other academic)
    Abstract [en]

    This paper investigates the emergence of complex syllable onsets through measurements of their duration compared to the duration of corresponding singleton syllable onsets. The results show that there is a difference in the progression in syllable onset duration that is dependent on subject age and onset structure.

  • 8.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    van Doorn, Jan
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Control of phonatory onset and offset in Parkinson patients following deep brain stimulation of the subthalamic nucleus and caudal Zona Incerta2012In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 18, no 7, p. 824-827Article in journal (Refereed)
    Abstract [en]

    Laryngeal hypokinesia is a common symptom in Parkinson’s disease (PD) that affects quality of life. Deep brain stimulation (DBS) is well recognized as a complementary method for treatment of motor symptoms in PD but the outcomes on patients’ control over phonatory alternation have yet not been clearly elucidated. The present study examined the effect of subthalamic nucleus STN-DBS (n=8, aged 51-72 yrs; median=63 yrs) and caudal Zona incerta cZi-DBS (n=8,aged 49-71 yrs; median=61 yrs) on control of onset and offset of phonation in connected speech. The patients were evaluated in a preoperatively (Med ON, 1.5 times the ordinary Levodopa dose) and 12 months postoperatively (Med ON, ordinary Levodopa dose). The results provided evidence of a progressive reduction in the ability to manifest alternations between voicing and voiceless states in a reading task. Mean proportion produced with inappropriate voicing increased from 47.6% to 55.3% and from 62.9% to 68.6% of the total duration for the two groups of patients between Pre-op and Post-op, Stim OFF evaluations. The medial and final parts of the fricative were more affected than the initial part, indicating an increased voicing lead into the following vowel. We propose that this reduction in phonatory control is be due to either progression of the disease, an effect of reduced Levodopa dosage or a microlesional effect. Patients’ proficiency in alternating between voiced and voiceless states in connected speech remained unaffected by both STN-DBS and cZi-DBS.

  • 9.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Czigler, Peter
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Using Voice Onset Time for Estimating Production Maturity of /sP/ clusters2005In: Proceedings from the X International Congress For the Study of Child Language, 2005Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    In previous investigations of the child’s acquisition of simple and complex syllable onsets in word initial position, a number of developmental trends have been observed. In the early stages of development, plosives have been reported to be substituted by a plosive at another, usually more fronted, place of articulation. Initial fricatives, on the other hand, have been reported to be substituted by plosive-like speech segments. At later stages of development, the child’s productions of plosives and fricatives in word initial position have been transcribed as increasingly adult-like.

    As to complex syllable onsets, children’s’ productions have been reported to go through stages of reduction or simplification at the onset of attempted cluster production. In an earlier investigation, the progression through this stage in development has been investigated acoustically through measurement of voice onset time and aspiration (Karlsson et al., 2002). The results indicated a strong tendency towards short lagged voice onset time at the onset of production of voiceless plosives and long lagged voice onset time at later stages, for the same speech sound category.

    This paper presents an investigation of the correlation between development in consonant quality and acoustic correlates of voicing and aspiration in the productions of children aged 77-218 weeks. Productions of target words with an initial fricative, voiced plosive, voiceless plosive or s+plosive cluster were collected from 21 children (12 male and 9 female) who were recorded at monthly intervals for up to one year per child. The total number of syllable onsets analysed was 4133. Using this corpus, the correlation of onset of production of plosives with non-fronted target places of articulation and the rise in mean voice onset time length are currently under investigation. The investigation includes correlations between time of reaching a steady state in voice onset time, aspiration length and the time of steady production of consonants with adult quality. Finally, correlation between the time of onset of production of complex syllable onsets will be considered and included in the model.

    The results from the correlation study will be presented and the implications for the study of consonant cluster production development will be discussed.

  • 10.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Applying the Vowel Formant Dispersion (VFD) method to the study of reduced or alterered vowel productions2012Conference paper (Other academic)
    Abstract [en]

    Formant centre frequencies are regularly used as acoustic measure of vowel quality because of the well established correlation between them and properties of vowel production(Fant, 1960). While it is recognised that it is important transform formant frequencies, as measured from the spectrogram, into relevant psychoacoustic scales when addressing issues of vowel perception, production studies are still largely based on the the raw, Hz-scaled, formant measurements. As a consequence, systematic studies of vowel articulation proficiency due to clinical conditions or effects of treatment are not easily afforded. 

    A number of derived measures have been proposed to capture whole-system effect of vowel production. Previous research has primarily used the calculated total area of formants measured from either [a], [u], [i] and [æ] or only [a], [u] and [i] productions, joined together to form a quadrilateral or a triangle (Vowel space area, VSA)(Kent & Kim, 2003). In the reduced articulatory range of hypokinetic dysarthria, VSA is expected to be reduced by the dysarthria, and increased due to successful treatment the patient’s articulatory range. 

    However, VSA has been proposed to be not powerful enough to capture effects on vowel articulation found specifically in patients with Parkinson’s disease (PD), and therefore not able to establish treatment effects.

    Two alternative measures have been proposed previously that are more focused towards specifically towards finding expansion and reductions in vowel spaces, the Vowel articulation index (VAI)(Roy, Nissen, Dromey, & Sapir, 2009) or Formant Centralization Ratio (FCR)(Sapir, Ramig, Spielman, & Fox, 2010). Both VAI and FCR has been shown to be able to establish significant reductions vowel articulation due to PD. Similar to VSA, however, the VAI and FCR measures do not given any detailed insight into the nature of the change in articulation. Further, all three measures reduces all obtained vowel formant measurements into a single metric, resulting in a substantial loss of statistical power and a considerable reduction in quality of intra-speaker models of articulatory proficiency. 

    In response to the problematic properties of previous metrics, a revised view of formant frequencies more suitable for studies of changes in vowel articulation has recently been outlined, along with a new metric (Vowel Formant Dispersion, VFD). The VFD view of vowel formants are more closely connected to properties of vowel articulation and therefore affords more more detailed interpretations to be drawn concerning speakers’ production proficiency and offers increased reliability of within speaker estimates of this proficiency. This paper presents a detailed view of how VFD may applied to clinical populations where vowel production is affected by the condition (e.g. hypokinetic dysarthria) or where production should be affected (e.g. transexual patients or in successful treatment of dysarthric patients). It will be shown that most aspects of the study of vowel articulation proficiency will be significantly enhanced by the VFD method.

  • 11.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Department of language studies.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Automatic acquisition of jitter and shimmer measurements across large sets of sustained vowel productions2012Conference paper (Other academic)
    Abstract [en]

    Measurements of jitter and shimmer are frequently employed to quantify laryngeal control and stability during voice production in patients(1-3). Accurate estimates of jitter and shimmer may be obtained from acoustic recordings of sustained vowels produced by patients using computer software implementing algorithms for their extraction (e.g. Praat(4) or MDVP(5)). The jitter and shimmer algorithms do not, in themselves, exclude non-stable productions and are influenced by the inclusion of silence in the analysed intervals. As a consequence, reliable measurements of jitter and shimmer are made by manually opening each sound file and selecting an interval for the computations. 

    The current paper proposes an alternative approach to afford a more efficient estimation of jitter and shimmer across a large set of sustained vowel recordings. Using information readily available in the acoustic signal and a combination of algorithms already available within the Praat program, a reliable method for automatic processing of only the sustained vowel in each recording of a large corpus is outlined. The method further affords the acquisition of multiple, repeatable, measurements of jitter and shimmer for sub-intervals of the vowel’s duration (applying more than one algorithm), which additionally provides information concerning the reliability of the jitter or shimmer estimates for a specific vowel  production. Comparisons with manually obtained measurements are made for the purpose of validation of the segmentation method.

  • 12.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Letter to the Editor2012In: Journal of Voice, ISSN 0892-1997, E-ISSN 1873-4588, Vol. 26, no 5, article id 676.e1Article in journal (Other academic)
  • 13.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Department of language studies.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Vowel formant dispersion as a measure of articulation proficiency2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, Vol. 132, no 4, p. 2633-2641Article in journal (Refereed)
    Abstract [en]

    The articulatory range of a speaker has previously been estimated by the shape formed by first and second formant measurements of produced vowels. In a majority of the currently available metrics, formant frequency measurements are reduced to a single estimate for a condition, which has adverse consequences for subsequent statistical testing. Other metrics provide estimates of size of vowel articulation changes only, and do not provide a method for studying the direction of the change. This paper proposes an alternative approach. Vowel formant frequencies are re-defined as vectors originating from a defined center point of the vowel space fixed to a basic three-vowel frame. The euclidian length of the vectors, the Vowel Formant Dispersion (VFD), can be compared across conditions for evidence of articulatory expansions or reductions across conditions or speaker groups. Further, the angle component of the vowel vectors allows for analyses of direction of the reduction or expansion. Based on the range of investigations afforded by the VFD metric, and simulation experiments that compare its statistical properties with those of other proposed metrics, it is argued that the VFD procedure offers an enhanced view of vowel articulation change over rival metrics.

  • 14.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Hartelius, Lena
    Institute of Neuroscience and Physiology, Department of Health and Rehabilitation, University of Gothenburg, Gothenburg, Sweden.
    How Well Does Diadochokinetic Task Performance Predict Articulatory Imprecision?: Differentiating Individuals with Parkinson's Disease from Control Subjects2019In: Folia Phoniatrica et Logopaedica, ISSN 1021-7762, E-ISSN 1421-9972, Vol. 71, no 5-6, p. 251-260Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To investigate whether syllables produced in an oral diadochokinetic (DDK) task may be quantified so that persons with Parkinson's disease (PD) perceived to have reduced articulatory precision when reading may be correctly identified using that quantification.

    PATIENTS AND METHODS: Syllable sequences from 38 speakers with PD and 38 gender- and age-matched control speakers (normal controls [NC]) were quantified acoustically and evaluated in terms of (1) the speakers' ability to accurately predict speaker group membership (PD or NC) and (2) their ability to predict reduced/non-reduced articulatory precision.

    RESULTS: A balanced accuracy of 80-93% in predicting speaker group membership was achieved. The best measures were related to the proportion of a syllable made up of a vowel, amplitude slope and syllable-to-syllable variation in duration and amplitude. The best material was that based on /ka/. Reduced articulatory precision was accurately predicted from DDK measures in 89% of the samples. Release-transient prominence and voicing during the onset of plosives were particularly strong predictors.

    CONCLUSIONS: DDK sequences can predict articulatory imprecision as observed in another speech task. The linking of performance across speech tasks probably requires measures of stability in syllable durations and amplitudes, as well as measures of subsyllabic acoustic features.

  • 15.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Hartelius, Lena
    Göteborgs universitet.
    How well does DDK task performance predict fluent speech articulation?2018Conference paper (Other academic)
    Abstract [en]

    The oral diadokochinesia (DDK) task is an established tool for assessing speech motor control that has been used across a range of conditions. The predominant outcome measure reported after the patient have performed the task is the maximum syllable rate achieved by the patient. More recent reports have also highlighted stability in pace of the sequence as quantifications that may be indicative of speech impairment. While the DDK task affords quick and easy administration, concerns have been raised regarding the strength of association between DDK task performance and patients’s articulation in fluent speech. It may not be assumed that a reduced DDK rate or rate stability will cause fluent speech also to be perceived as slowed or dysrhythmic. And, patients may well improve their syllable rate at the expense of articulatory quality, which is currently not easily captured in an objective outcome measure.

    We report here on an effort to assess to what degree information from an expanded quantification of DDK sequences may be used identify patients with dysarthria and to model clinical assessments of fluent speech. Acoustic quantifications of the consonant and consonant-vowel relationship are combined with previously used measures, and applied to manually processed DDK sequences produced by patients with Parkinson’s disease and normal control speakers. We observe how well these quantifications may form the basis for accurate identification of patients among normal controls, and predict the outcome of blinded and randomized clinical assessments of patients’ production of fluent speech.Rapid repetition of CV syllables (oral diadochokinesis, DDK) puts pressure on the speech motor system in order to afford detection of a deteriorating articulatory ability.

    This study assessed

    1.  how well objective quantifications of DDK

      sequences can be used to identify PD speakers

      among age matched controls (NC), and

    2. how well a reduced articulatory ability in PD

      speakers may be predicted using quantifications of DDK sequences performed in the same recording session.

    The comprehensive DDK sequence quantification achieved a 93% classification accuracy for speaker group and a 79% accuracy for reduced fluent speech articulatory quality. 

  • 16.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Landgren, Tomas
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Utveckling av Voice Onset Time hos svenska barn2006In: Tionde Nordiska Barnspråkssymposiet / [ed] Mårten Eriksson, Antti Ylikiiskilä & Eva Berglund, Gävle: Högskolan i Gävle , 2006, p. 69-75Conference paper (Other academic)
  • 17.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Malinova, Elin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Voice Tremor Outcomes of Subthalamic Nucleus and Zona Incerta Deep Brain Stimulation in Patients With Parkinson Disease2019In: Journal of Voice, ISSN 0892-1997, E-ISSN 1873-4588, Vol. 33, no 4, p. 545-549Article in journal (Refereed)
    Abstract [en]

    Objectives: We aimed to study the effect of deep brain stimulation (DBS) in the subthalamic nucleus (STN) and caudal zona incerta (cZi) on level of perceived voice tremor in patients with Parkinson disease (PD).

    Study Design: This is a prospective nonrandomized design with consecutive patients.

    Methods: Perceived voice tremor was assessed in patients with PD having received either STN-DBS (8 patients, 5 bilateral and 3 unilateral, aged 43.1-73.6 years; median = 61.2 years) or cZi-DBS (14 bilateral patients, aged 39.0-71.9 years; median = 56.6 years) 12 months before the assessment. Sustained vowels that were produced OFF and ON stimulation (with simultaneous L-DOPA medication) were assessed perceptually in terms of voice tremor by two raters on a four-point rating scale. The assessments were repeated five times per sample and rated in a blinded and randomized procedure.

    Results: Three out of the 22 patients (13%) were concluded to have voice tremor OFF stimulation. Patients with PD with STN-DBS showed mild levels of perceived voice tremor OFF stimulation and a group level improvement. Patients with moderate/severe perceived voice tremor and cZi-DBS showed marked improvements, but there was no overall group effect. Six patients with cZi-DBS showed small increases in perceived voice tremor severity.

    Conclusions: STN-DBS decreased perceived voice tremor on a group level. cZi-DBS decreased perceived voice tremor in patients with PD with moderate to severe preoperative levels of the symptom.

  • 18.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Pitch variability in patients with Parkinson’s disease: effects of deep brain stimulation of caudal zona incerta and subthalamic nucleus2013In: Journal of Speech, Language and Hearing Research, ISSN 1092-4388, E-ISSN 1558-9102, Vol. 56, no 1, p. 150-158Article in journal (Refereed)
    Abstract [en]

    Objective The purpose of the present study was to examine the effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and the caudal zona incerta (cZi) pitch characteristics of con- nected speech in patients with Parkinson’s disease (PD).

    Methods Sixteen patients were evaluated preoperatively and 12 months after DBS surgery. Eight pa- tients were implanted in the STN (aged 51-72 yrs; xC=63 yrs). Six received bilateral implanta- tion and two unilateral (left) implantation. Eight patients were bilaterally implanted in the cZi (aged 49-71 yrs; xC=60.8 yrs). Preoperative assessments were made after an L-Dopa challenge (approximately 1.5 times the ordinary dose). All postoperative examinations were made off and on stimulation, with a clinically optimized dose of L-dopa. Measurements of pitch range and var- iability were obtained from each utterance in a recorded read speech passage.

    Results Pitch range and coefficient of variation showed an increase in patients under STN-DBS. Patients under cZi-DBS showed no significant effects of treatment on investigated pitch properties.

    Conclusions STN-DBS was shown to increase pitch variation and range. The results provided no evidence of cZi-DBS having a beneficial effect on PD patients’ pitch variability. 

  • 19.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Department of language studies. Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Blomstedt, Patric
    Linder, Jan
    Nordh, Erik
    van Doorn, Jan
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Articulatory closure proficiency in Parkinson's disease patients following deep brain stimulation of the subthalamic nucleus and caudal zona incerta.2014In: Journal of Speech, Language and Hearing Research, ISSN 1092-4388, E-ISSN 1558-9102, Vol. 57, p. 1178-1190Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE

    The present study aimed at comparing the effects of deep brain stimulation (DBS) treatment of the subthalamic nucleus (STN) and the caudal zona incerta (cZi) on Parkinson's disease patients' proficiency in achieving oral closure and release during plosive production. METHODS Nineteen patients were evaluated preoperatively and 12 months after DBS surgery. Nine patients were implanted in the STN, seven bilaterally and two unilaterally (left). Ten were bilaterally implanted in the cZi. Postoperative examinations were made off and on stimulation. All patients received simultaneous L-dopa treatment in all conditions. For a series of plosives extracted from a reading passage, absolute and relative measures of duration of frication and amplitude of plosive release were compared between conditions within each treatment group. RESULTS Relative duration of frication increased in voiceless plosives in the on stimulation condition in cZi patients. Similar trends were observed across the data set. Duration of pre-release frication and the release peak prominence increased in voiceless plosives on stimulation for both groups. CONCLUSIONS The increased release prominence suggests that patients achieved a stronger closure gesture due to DBS, but that the increased energy available resulted in increased frication.

  • 20.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Kvantifiering av inlärning av tonande/tonlös kontrast med hjälp av Voice Onset Time2006In: Tionde Nordiska Barnspråkssymposiet / [ed] Mårten Eriksson, Antti Ylikiiskilä & Eva Berglund, Gävle: Högskolan i Gävle , 2006, p. 60-68Conference paper (Other academic)
  • 21.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    /sP/ consonant clusters in Swedish: Acoustic measurements of phonological development2005In: Developmental Paths in Phonological Acquisition: Special issue of Leiden Papers in Linguistics 2.1, 2005Conference paper (Other academic)
    Abstract [en]

    This paper presents a cross-sectional and longitudinal investigation into the development of a contrast in voicing production in simple and complex consonant clusters for 21 children. The results showed that, although the group results indicated a progression that may have been caused either by development in articulatory proficiency or by an growing underlying representation, individual children develop in a manner that is not consistent with a developmental model postulating only articulatory development.

  • 22.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    The use of relativization in the regional dialect of Swedish spoken in Burträsk2002In: Relativisation in the North Sea Littoral, Lincom Europa , 2002, p. 97-107Chapter in book (Other academic)
  • 23.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Czigler, Peter E.
    van Doorn, Jan
    Faculty of Medicine, Clinical Sciences.
    Acoustic correlates of voicing in a child's production of plosives2002In: Proceedings of the 9th Australian International Conference on Speech Science & Technology, 2002Conference paper (Other academic)
  • 24.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Department of language studies.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Department of language studies.
    Svonni, Michael
    Umeå University, Faculty of Arts, Department of language studies.
    Van Doorn, Janis
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Wenstedt, Ola
    The acoustic manifestation of consonant gradation in Northern Sami2008In: Journal of the Acoustical Society of America, Vol. 123, no 5 (part 2), p. 3885-Article in journal (Refereed)
  • 25.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    van Doorn, Jan
    Umeå University, Faculty of Medicine, Clinical Sciences, Speech and Language Therapy.
    Czigler, Peter E.
    Då or Tå, Pår or Bår - Seeing is believing!2003In: Proceeding of the 15th International Congress of Phonetic Sciences, 2003Conference paper (Other academic)
    Abstract [en]

    Several acoustic properties of plosives have been established as correlates of voicing contrast, including voice onset time (VOT), F1 cut-back, aspiration duration and initial F1 and F2 transition. Therefore, acquisition of the voicing contrast for plosives could be viewed as gaining the ability to combine interacting acoustic cues in an adult-like manner, resulting in a large number of possible developmental routes. The presented investigation examined initial plosives produced by one child from ages 18¿31 months that had been judged as voiced in an auditory analysis. The results show that some perceptually voiced and unaspirated plosives (elicited using voiceless targets) were produced with VOT values within the range of voiceless plosives for adult speakers of Swedish, and also had increased duration of high frequency, aperiodic friction after plosive release. It was conjectured that the child was attempting a voicing contrast by using increased VOT and increased duration of aperiodic friction that were not perceptible to adult listeners.

  • 26.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Unger, Elin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Wahlgren, Sofia
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Zafar, Hamayun
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Deep brain stimulation of caudal zona incerta and subthalamic nucleus in patients with Parkinson’s disease: effects on diadochokinetic rate2011In: Parkinson’s Disease, ISSN 2042-0080, Vol. 2011, p. 605607-Article in journal (Refereed)
    Abstract [en]

    The hypokinetic dysarthria observed in Parkinson's disease (PD) affects the range, speed, and accuracy of articulatory gestures in patients, reducing the perceived quality of speech acoustic output in continuous speech. Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) and of the caudal zona incerta (cZi-DBS) are current surgical treatment options for PD. This study aimed at investigating the outcome of STN-DBS (7 patients) and cZi-DBS (7 patients) in two articulatory diadochokinesis tasks (AMR and SMR) using measurements of articulation rate and quality of the plosive consonants (using the percent measurable VOT metric). The results indicate that patients receiving STN-DBS increased in articulation rate in the Stim-ON condition in the AMR task only, with no effect on production quality. Patients receiving cZi-DBS decreased in articulation rate in the Stim-ON condition and further showed a reduction in production quality. The data therefore suggest that cZi-DBS is more detrimental for extended articulatory movements than STN-DBS.

  • 27.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Arts, Department of language studies.
    Unger, Elin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Wahlgren, Sofia
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Treatment effects in voice onset time of plosives associated with deep brain stimulation of the subthalamic nucleus and the caudal zona incerta2012In: Journal of medical speech-language pathology, ISSN 1065-1438, Vol. 20, no 4, p. 65-69Article in journal (Refereed)
    Abstract [en]

    The present study investigated the effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and the caudal zona inserta (cZi) on motor control and coordination in plosives. A total of 2520 plosive productions, recorded during production of alternate motion rate and sequential motion rate tasks, were measured for voice onset time (VOT) when measurement was possible. Failed measurements were classified by the underlying cause. The resulting data were analyzed separately for each place of articulation of the intended plosive and compared with the articulatory properties of plosives not meeting the requirements for VOT measurement. The results showed no consistent overall stimulation effect in VOT regardless of place of articulatory closure. Furthermore, no overall pattern concerning the distribution of factors causing failures to measure VOT was observed. Instead, the results suggest a more complex interaction among place of articulation, speech task, and stimulation target in the determination of treatment effects of DBS in patients with Parkinson's disease (PD). The results further suggest that VOT may not provide a robust estimate of treatment effects in articulatory proficiency related to plosive production in patients with PD.

  • 28.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Zetterholm, Elisabeth
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics. Lingvistik.
    Development of a Gender Difference in Voice Onset Time2004In: Proceedings of the 10th Australian International Conference on Speech Science & Technology, 2004Conference paper (Refereed)
    Abstract [en]

    This paper investigates the effect of gender on voice onset time distribution at three stages of speech development. Two subject groups consisting of children, aged approximately 3 and 9 years, were compared to adult speakers regarding voice onset time of initial plosives. The results showed significant gender effects in the aspirated plosives in the young subjects that were not present in the plosives produced by adults. It is hypothesised that the effect of gender at the earlier stages of develpment may be due to the differences in airflow intensity and variability.

  • 29.
    Landgren, Tomas
    et al.
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Sullivan, Kirk P H
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    Eriksson, Anders
    Umeå University, Faculty of Arts, Philosophy and Linguistics.
    A comparison of the use of relatization in the Swedish regional dialects spoken in Burträsk and Ström2002In: Preceedings to the XI:th International Conference on Methods in Dialectology, 2002Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The data presented in this paper comes from tape recordings made as part of the dialect project "The phonetics and phonology of the Swedish dialects around the year 2000, SWEDIA 2000". Karlsson and Sullivan (in press) investigated relative marker usage in Burträsk. Due to its situation at the northern periphery of the Swedish dialect rectangle and as a non-coastal settlement, Karlsson and Sullivan (in press) believed that the Burträsk dialect may well reveal traces of older variants of Swedish. As the SWEDIA dialect database is balanced for informant gender and age, it permitted the investigation of both the infiltration of standard Swedish relativizers into this northern dialect of Swedish and the influence of gender in any other change that may have occurred during the twentieth century. From the tape-recordings of eight informants' spontaneous speech lasting a total of 7 hours and 35 minutes, Karlsson and Sullivan (in press) found a strong preference in the Burträsk dialect for relative clause constructions involving a moving (realized) subject, that relativization involving object movement is also used, but less frequently, and that in relative clauses involving the null relative marker, subject and object correlates occur with equal frequency. Further, no significant difference in relative marker usage was found due to either age or gender. Of particular note was that no examples of the use of constructions using a wh-word, such as vars or vilken/vilket were found in the data provided by any of the eight informants. Unlike, the complementizer som that was found in the data vars or vilken/vilket always imply a more formal, or standard, speaking style. This paper extends the Karlsson and Sullivan study by posing the same questions in relation to the dialect spoken in Ström and thereafter by comparing and constrasting the Ström data with the Burträsk data. Like Burträsk, Ström is a non-coastal settlement. It lies around 350km southwest of Burträsk and has since the middle ages been a trading centre. Of particular interest is that Ström lies in Jämtland, which was part of Norway until 1645. The comparative data presented in this paper may provide picture of how the use of relativization is affected when a settlement has contact with neighbouring dialects due to its position as a training centre and due to its less peripheral location within the Swedish Dialect Rectangle.

  • 30.
    Lohmander, Anette
    et al.
    Karolinska institutet.
    McAllister, Anita
    Karolinska institutet.
    Hansson, Kristina
    Lunds universitet.
    Hartelius, Lena
    Göteborgs universitet.
    Blom Johansson, Monica
    Uppsala universitet.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Samuelsson, Christina
    Linköpings universitet.
    Schalling, Ellika
    Karolinska institutet.
    Södersten, Maria
    Karolinska institutet.
    Östberg, Per
    Karolinska institutet.
    van Doorn, Jan
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Kommunikations- och sväljstörningar genom hela livet: ett logopediskt ståndpunktsdokument2017Report (Other academic)
    Abstract [sv]

    Den forskning som bedrivs inom logopedi i Sverige idag spänner över ett brett spektrum av medfödda, utvecklingsrelaterade och förvärvade kommunikationsstörningar på grund av röst-, tal- och språksvårigheter samt sväljstörningar. Precis som i andra länder pågår en snabb utveckling både mot en breddning av det urval av områden som det forskas kring och ett ökat fokus på nationellt samarbete. Även om de framsteg som görs inom respektive fält kan mätas genom de forskningsrapporter som publiceras av respektive forskargrupper, finns det ett behov av att granska vilka forskningsinsatser som bedrivs jämte det demografiska sammanhanget. I detta ståndpunktsdokument ger vi en översikt över logopediämnet och den forskning som bedrivs i Sverige. I en kubmodell illustreras hur kommunikations- och sväljstörningar kan beskrivas. Stratifierade (per åldersintervall) uppskattningar av prevalensen av kommunikations- och sväljstörningar ges baserat på 2016 års befolkningsstruktur. Genom att presentera dessa två komponenter identifieras forskningsområden och riktningar inom logopedi som behöver ges ökad uppmärksamhet i det kommande forskningsarbetet.

  • 31.
    Louise, Johansson
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Sofia, Möller
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neurophysiology.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Department of language studies. Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Word-level intelligibility after caudal zona incerta stimulation for Parkinson’s disease2014In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 130, no 1, p. 27-33Article in journal (Refereed)
    Abstract [en]

    Objectives – To investigate the effect of caudal zona incerta-deep brain stimulation (cZi-DBS) on word-level speech intelligibility in patients with Parkinson’s disease, under both an optimal listening condition and a simulated more naturalistic listening condition.

    Materials and methods – Spoken single words were extracted from read samples collected from 10 bilaterally implanted patients with PD pre- and post-cZi-DBS. Intelligibility was assessed through a transcription task performed by 32 naive listeners under two listening conditions: (i) with low-amplitude conversational speech added as background and (ii) with no added background noise. The listeners′ responses were scored in terms of agreement with the intended words.

    Results – Post-operatively, the total intelligibility score was significantly lower when cZi stimulation was switched on compared with off, for both listening conditions (with and without added background noise). Intelligibility was also significantly lower on stimulation compared with preoperative recordings, but only when assessed in the listening condition without background noise. The listening condition with added background noise resulted in significantly lower intelligibility scores compared with the no added noise condition for all stimulation conditions.

    Conclusions – The results of this study indicate that cZi-DBS in patients with PD can be detrimental to word-level speech intelligibility. 

  • 32.
    Lundgren, Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Saeys, Thomas
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Olofsson, Katarina
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Linder, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Nordh, Erik
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Zafar, Hamayun
    Umeå University, Faculty of Medicine, Department of Odontology, Clinical Oral Physiology.
    Doorn, Jan van
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Deep brain stimulation of caudal zona incerta and subthalamic nucleus in patients with Parkinson’s disease: effects on voice intensity2011In: Parkinson’s Disease, ISSN 2042-0080, Vol. 2011, p. 658956-Article in journal (Refereed)
    Abstract [en]

    Deep brain stimulation of the subthalamic nucleus (STN-DBS) in patients with Parkinson’s disease (PD) affects speech in small, inconsistent ways. However, voice intensity generally increases. Recently the caudal zona inserta (cZi) has been investigated as an alternate target in DBS treatment of PD. The effects of cZi-DBS on voice intensity have not yet been investigated. The aim of this study was to compare the voice intensity effects of cZi-DBS and STN-DBS in PD patients. Voice intensity during reading and intensity decay during rapid syllable repetition were measured for eight STN-DBS and eight cZi-DBS patients in a pre-surgical baseline and then on- and off-stimulation 12 months after surgery. Voice intensity on-stimulation was larger than off-stimulation for the STN-DBS patients, but smaller for the cZi-DBS patients. There were no significant changes in intensity decay. The results suggest that cZi and STN are involved differently in neuromuscular control of the speech respiratory subsystem.

  • 33.
    Mennen, Ineke
    et al.
    ESRC Centre for Research on Bilingualism, Bangor University.
    Chen, Aujo
    Max Planck Institute for Psycholinguistics, Nijmegen.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Department of language studies.
    Characterising the internal structure of learner intonation and its development over time2010In: Proceedings of The 6th International Symposium on the Acquisition of Second Language Speech (Newsounds 2010), 2010Conference paper (Refereed)
    Abstract [en]

    This paper describes the internal structure and longitudinal development of L2 learner intonation in two groups of three speakers from structurally different source languages (Punjabi and Italian) learning the same target language (English). The speakers were recently arrived immigrants in their host country and were followed over a period of thirty months. During this period, their intonation was analysed at two longitudinal points along three dimensions of the intonation system: (i) the inventory of structural elements (pitch accents and boundary tones); (ii) the way these are realised; and (iii) their distribution. Some attention is also paid to the functional aspect of learner intonation. Results show that there are many similarities across speakers in most dimensions of intonation. It seems that learners start out with the same inventory of structural elements from the start of their learning, regardless of the source language of the learners, although there are some differences in the frequency of use of certain patterns and the rate at which the system develop

  • 34.
    Sandström, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Long-term effects of unilateral deep brain stimulation on voice tremor in patients with essential tremor2019In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 60, p. 70-75Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Voice tremor (VT) is a common symptom of Essential tremor (ET). Deep brain stimulation (DBS) is an established treatment for ET overall, however, its effect on VT is less clear. The aim of this study was to evaluate long-term effects of DBS on VT and to investigate how VT symptoms develop over time in patients with ET.

    METHODS: VT scores for the cohort of 81 ET patients that had undergone DBS surgery in the caudal zona incerta (cZi) were analyzed retrospectively. Thirty-four patients had preoperative VT and long-term evaluations were available for 19 patients. Longitudinal effects of cZi-DBS were investigated 1, 3 and 5 years postoperatively. VT progression was evaluated based on preoperative-, and off stimulation postoperative assessments.

    RESULTS: Unilateral cZi-DBS reduced average voice tremor by 58% at the 3-year follow-up and by 67% 5 years after surgery. Four patterns of VT development were identified among patients, and the effectiveness of cZi-DBS in alleviating voice tremor symptoms showed differing patterns for these subgroups.

    CONCLUSIONS: This retrospective analysis of a small cohort of patients suggests that cZi-DBS may reduce VT in the long-term for patients with ET overall, but the pattern of VT progression likely influences the effectiveness of the treatment. These results also suggest that unilateral cZi-DBS may be more efficacious when treating patients with mild to moderate VT. A prospective, blinded, controlled clinical trial in patients with ET is needed to determine developmental patterns of VT, and the safety and efficacy of cZi-DBS for the treatment of VT.

  • 35.
    Sandström, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences.
    Voice Tremor Response to Deep Brain Stimulation in Relation to Electrode Location in the Posterior Subthalamic Area2019In: World Neurosurgery: X, ISSN 2590-1397, Vol. 3, p. 1-9, article id 100024Article in journal (Refereed)
    Abstract [en]

    Background: Deep brain stimulation of the motor thalamus or the posterior subthalamic area (PSA) shows promising results for patients with voice tremor, although only for about 50% of patients. There are indications that voice tremor requires more focused stimulation within the target area compared with hand tremor. The objective of the present study was to determine the most efficient location for reducing voice tremor within the PSA.

    Methods: Thirty-seven patients with essential tremor were evaluated off stimulation and in a set of experimental conditions with unilateral stimulation at increasing amplitude levels. Two listeners performed blinded assessments of voice tremor from recordings of sustained vowel productions.

    Results: Twenty-five patients (68%) had voice tremor. Unilateral stimulation reduced voice tremor for the majority of patients, and only 6 patients had poor outcomes. Contacts yielding efficient voice tremor reduction were deeper relative to the midcommissural point (MCP) and more posterior relative to the posterior tip of the subthalamic nucleus (pSTN) (z MCP = –3.1, y pSTN = –0.2) compared with poor contacts (z MCP = –0.7, y pSTN = 1.0). High-amplitude stimulation worsened voice tremor for 7 patients and induced voice tremor in 2 patients. Hand tremorimproved to a greater extent than voice tremor, and improvements could be seen throughout the target area.

    Conclusions: Our results indicate that efficient voice tremor reduction can be achieved by stimulating contacts located in the inferior part of the PSA, close or slightly posterior to the pSTN. We observed cases in which voice tremor was induced by high-amplitude stimulation.

  • 36.
    Sandström, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Hägglund, Patricia
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Johansson, Louise
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Speech intelligibility in Parkinson's disease patients with zona incerta deep brain stimulation2015In: Brain and Behavior, ISSN 2162-3279, E-ISSN 2162-3279, Vol. 5, no 10, article id e00394Article in journal (Refereed)
    Abstract [en]

    Objectives

    To investigate the effects of l-dopa (Levodopa) and cZi-DBS (deep brain stimulation in caudal zona incerta) on spontaneous speech intelligibility in patients with PD (Parkinson's disease).

    Materials and Methods

    Spontaneous utterances were extracted from anechoic recordings from 11 patients with PD preoperatively (off and on l-dopa medication) and 6 and 12 months post bilateral cZi-DBS operation (off and on stimulation, with simultaneous l-dopa medication). Background noise with an amplitude corresponding to a clinical setting was added to the recordings. Intelligibility was assessed through a transcription task performed by 41 listeners in a randomized and blinded procedure.

    Results

    A group-level worsening in spontaneous speech intelligibility was observed on cZi stimulation compared to off 6 months postoperatively (8 adverse, 1 positive, 2 no change). Twelve months postoperatively, adverse effects of cZi-DBS were not frequently observed (2 positive, 3 adverse, 6 no change). l-dopa administered preoperatively as part of the evaluation for DBS operation provided the overall best treatment outcome (1 adverse, 4 positive, 6 no change).

    Conclusions

    cZi-DBS was shown to have smaller negative effects when evaluated from spontaneous speech compared to speech effects reported previously. The previously reported reduction in word-level intelligibility 12 months postoperatively was not transferred to spontaneous speech for most patients. Reduced intelligibility due to cZi stimulation was much more prominent 6 months postoperatively than at 12 months.

  • 37.
    Sandström, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Unilateral Left Deep Brain Stimulation of the Caudal Zona Incerta Is Equally Effective on Voice Tremor as Bilateral Stimulation: Evidence from 7 Patients with Essential Tremor2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 3, p. 157-161Article in journal (Refereed)
    Abstract [en]

    BACKGROUND/AIMS: Deep brain stimulation (DBS) is less effective on voice tremor than arm tremor, and it is generally assumed that successful voice tremor treatment requires bilateral DBS and possibly more precise thalamic stimulation. However, recent findings suggest that these assumptions should be reconsidered.

    OBJECTIVES: To evaluate whether unilateral DBS targeting the caudal zona incerta (cZi) may be sufficient to alleviate voice tremor in patients with essential tremor, or whether bilateral stimulation is needed.

    METHODS: Seven patients with voice tremor off stimulation were evaluated during bilateral stimulation using their clinical settings, and during unilateral left stimulation in iterations with increasing stimulation amplitude. Two expert listeners assessed voice tremor severity in all samples in a blinded procedure.

    RESULTS: Six patients had comparable or better effects with unilateral left stimulation compared to bilateral stimulation. For the seventh patient, unilateral DBS at a slightly higher amplitude achieved similar results as bilateral DBS. Overall, high-amplitude stimulation did not appear to be beneficial on voice tremor.

    CONCLUSIONS: Unilateral left and bilateral cZi-DBS had comparable effects on voice tremor in the investigated group of 7 patients. This finding suggests that the assumption that bilateral DBS is required to treat voice tremor may need to be reconsidered.

  • 38.
    van Doorn, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Arts, Department of language studies.
    Sullivan, Kirk P. H.
    Umeå University, Faculty of Arts, Department of language studies.
    An acoustic investigation of the Swedish child’s acquisition of obstruent place of articulation2008In: Acoustics'08 Paris : June 29 - July 4, 2008, Paris: Société Française d'Acoustique (SFA) , 2008, p. 681-686Conference paper (Other academic)
    Abstract [en]

    Speech produced by children in the initial stages of development does generally not uphold as many phonetic distinctions as speech sounds produced by adults. A child's productions of different target words may therefore have similar acoustic properties and result in homonyms being perceived by the adult observer. This study presents a longitudional investigation into the development of place of articulation from non‐distinctive to distinctive productions in word‐initial obstruents produced by 22 Swedish children (aged 18 ‐ 48 months). The data was collected through monthly recordings, approximatelly one year per child. The acoustic correlates analysed were spectral diffuseness, spectral skewness and spectral tilt for plosives and spectral skewness, spectral kurtosis, spectral variance and F2 onset frequency for fricatives. The results show a developmental trend in spectral skewness that is indicative of a increasing number of acquired phonetic contrasts. Spectral tilt change, F2 onset frequency, spectral mean and spectral variance provide evicence of within‐category refinement wich is argued to be caused primarilly by advancements in motor control.

  • 39.
    van Doorn, Janis
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Influence of speech task and utterance length on measurement of pitch variability in the speech of Parkinson's disease patients after deep brain stimulation2013In: Movement Disorders, ISSN 0885-3185, E-ISSN 1531-8257, Vol. 28, no Supplement 1, p. S448-Article in journal (Refereed)
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