ID 64 – Involvement of A-delta sensory fibres in amyotrophic lateral sclerosis

Abstract

Background Detection of any sensory abnormality in nerve conduction studies (NCSs) usually leads the physician to exclude amyotrophic lateral sclerosis (ALS). However, increasing evidence suggested that ALS is a multisystem disorder that also involves the sensory nerves. Objective In this study we wanted to see if proximal and distal large diameter sensory nerves were deteriorated in ALS. Methods 15 definite-ALS patients and 27 healthy subjects were evaluated based on distal sensory NCSs [i.e., antidromic dorsal sural (DS) and orthodromic medial plantar (MP)] in addition to standardized proximal sensory NCSs [i.e., unilateral median sensory and bilateral sural (SU) nerves]. Also, somatosensory evoked potentials (SEPs) in upper (UE-) and lower extremities (LE-) were recorded. Results ALS patients had abnormal DS-NCSs (9 patients bilaterally and 3 patients unilaterally) and MP-NCSs (6 patients bilaterally and 1 patient unilaterally) while median sensory- and right SU-NCS were abnormal in 1 and 4 patients, respectively. Also, UE- and LE-SEPs were abnormal in 5 and 7 patients, respectively. Conclusions Distal sensory NCSs probably deteriorate earlier and more than proximal sensory NCSs in ALS. Key message A-beta sensory fibers are involved as well as corticospinal fibers in ALS.