Quantitative thermal sensory testing in patients with amyotrophic lateral sclerosis using reaction time exclusive method of levels (MLE).

OBJECTIVES: Quantitative thermal sensory testing (QST) systems are used for the noninvasive quantification of sensory nerve function including the small myelinated and unmyelinated fibres which is not provided by classical sensory nerve conduction studies. Although Amyotrophic Lateral Sclerosis (ALS) is a pure motor disorder, nevetheless involvement of the sensory fires has been reported occasionally by various techniques. In the present study Reaction Time Exclusive Method of Levels (MLE) was used to detect somatic small fibre involvement in ALS patients with no sensory abnomalities on routine NCS.

MATERIAL & METHOD: Twenty patients of clinically definite ALS, were evaluated with QST using the reaction time exclusive method of Levels (MLE) for detecting the thresholds of cold sensation (CS) and warm sensation (WS). They were compared with 20 age matched controls.

RESULTS: No abnormalities were detected in the thresholds for CS and WS in patients with ALS as compared to the controls.

CONCLUSION: Thus ALS is essentially a pure motor disorder with normal thermal thresholds as revealed by QST.