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Near infrared spectroscopy (NIR) and skin impedance (IMP) spectroscopy are two methods suggested for diagnoses of diseases inducing adverse effects in skin. The reproducibility of these methods and their potential value in non-invasive diagnostics were investigated. Measurements were performed in vivo on healthy skin at five anatomic body sites on eight young women. partial least squares discriminant analysis showed that both methods were useful for classification of the skin characteristics at the sites. Inter-individually the NIR model gave 100% correct classification while the IMP model provided 92%. Intra-individually the NIR model gave 88% correct classification whereas the IMP model did not provide any useful classification. The correct classification was increased to 93% when both datasets were combined, which demonstrates the value of adding information. Partial least squares discriminant analysis gave 72% correct predictions of skin sites while the combined model slightly improved to 73%.

Background/purpose: Near-infrared (NIR) spectroscopy and skin impedance (IMP) measurements are useful techniques for objective diagnostics of various skin diseases. Here, we present a combined probe head for simultaneous, time-saving NIR spectroscopy and skin impedance measurements. The probe also ensures that both measurements are performed under equal conditions and at the same skin location.

Methods: Finite element method simulations were performed for evaluation of the impedance. In vivo skin measurements were performed and combined NIR and impedance spectra were analysed by means of multivariate methods with respect to body location, age and gender. The classification rate was determined by a planar discriminant analysis. Reproducibility was investigated by calculation of scatter values and statistical significance between overlapping groups was assessed by the calculation of intra-model distances, q.

Results: The novel probe yielded rapid reproducible results and was easy to manage. Significant differences between skin locations and to a lesser extent age groups and gender were demonstrated.

Conclusion: With the novel probe, statistically significant differences between overlapping classes in score plots can be confirmed by calculating intra-model distances. The influence of molecular differences in the skin at different body locations is larger than the influence of gender or age and therefore relevant reference measurements are discussed.

Background/purpose: Near infrared (NIR) and impedance spectroscopy can be used for clinical skin measurements and need to be evaluated for possible confounding factors; (a) are skin conditions of the patient and the subsequent skin measurements influenced by alcohol and/or coffee consumption and (b) are measurements of dysplastic naevi (DN) reproducible over time and significantly different compared to reference skin.

Methods: NIR and skin impedance spectroscopic data were analysed multivariately. In the first study, the skin characteristics of 15 healthy individuals were examined related to body location, gender, individual differences, and consumption of coffee or alcohol. The second study included five patients diagnosed with dysplastic naevi syndrome (DNS). Measurements were taken on DN and reference skin over time.

Results: In the first study, body location and gender had a major influence on measurement scores. Inter-individual skin characteristics and coffee or alcohol effects on skin characteristics were of minor importance. In the second study, it was shown that DN can be differentiated from reference skin and the measurements are stable over time.

Conclusions: Moderate consumption of alcohol and coffee did not influence the results of the measurements. It is possible to follow, stable or changed, characteristics of DN over time.

Background/purpose: An early diagnosis of cutaneous malignant melanoma is of high importance for good prognosis. An objective, non-invasive instrument could improve the diagnostic accuracy of melanoma and decrease unnecessary biopsies. The aim of this study was to investigate the use of Near infrared and skin impedance spectroscopy in combination as a tool to distinguish between malignant and benign skin tumours.

Methods: Near infrared and skin impedance spectra were collected in vivo on 50 naevi or suspect melanomas prior to excision. Received data was analysed with multivariate techniques and the results were compared to histopathology analyses of the tumours. A total of 12 cutaneous malignant melanomas, 19 dysplastic naevi and 19 benign naevi were included in the study.

Results: The observed sensitivity and specificity of the proposed method were 83% and 95%, respectively, for malignant melanoma.

Conclusions: The results indicate that the combination of near infrared and skin impedance spectroscopy is a promising tool for non-invasive diagnosis of suspect cutaneous malignant melanomas.