Quantitative thermal sensory testing — value of testing for both cold and warm sensation detection in evaluation of small fiber neuropathy

Abstract

Objective: Small fiber neuropathy is a common neurological disorder, often missed or ignored by physicians, since examination and routine nerve conduction studies are usually normal in this condition. Many methods including quantitative thermal sensory testing are currently being used for early detection of this condition, so as to enable timely investigation and treatment. This study was conducted to assess the yield of quantitative thermal sensory testing in diagnosis of small fiber neuropathy. Material and methods: We included patients presenting with history suggestive of positive and/or negative sensory symptoms, with normal examination findings, clinically suggestive of small fiber neuropathy, with normal or minimally abnormal routine nerve conduction studies. These patients were subjected to quantitative thermal sensory testing using a Medoc TSA-II Neurosensory analyser at two sites and for two modalities. QST data were compared with those in 120 normal healthy controls. Results: Twenty-five patients (16 males, 9 females) with mean age 46.8 ± 16.6 years (range: 21–75 years) were included in the study. The mean duration of symptoms was 1.6 ± 1.6 years (range: 3 months–6 years). Eighteen patients (72%) had abnormal thresholds in at least one modality. Thermal thresholds were normal in 7 out of the 25 patients. Conclusion: This study demonstrates that quantitative thermal sensory testing is a fairly sensitive method for detection of small fiber neuropathy especially in patients with normal routine nerve conduction studies.