Quantitative thermal sensory testing in patients with monomelic amyotrophy.

ABSTRACT

BACKGROUND: Quantitative thermal sensory testing (QST) is a non-invasive method to assess somatic small fibre dysfunction, which is not evaluated with routine nerve conduction studies (NCS). Monomelic amyotrophy (MMA), is a pure motor disorder with no sensory abnormalities on routine NCS, and has not been evaluated using QST. AIMS AND OBJECTIVE: Present study aimed to evaluate somatic small fibre involvement in MMA patients. Forty patients with MMA with no sensory abnormalities or routine NCS were evaluated using QST for thresholds of cold sensation (CS), warm sensation (WS), cold pain (CP) and warm pain (WP), using method of limits. These were compared with 40 age-matched controls. RESULTS: No abnormalities in thresholds for CS, WS, CP and WP were found in MMA group as compared to controls. CONCLUSION: QST thus failed to demonstrate any abnormality. Hence we conclude that MMA is a pure motor disorder, with no involvement of somatic small sensory fibres (A delta and C).