Comparing axonal excitability in past polio to amyotrophic lateral sclerosis

: Poliomyelitis causes selective destruction of anterior horn cells and usually has a stable disease course post‐infection. We assessed the excitability characteristics in patients with a stable course after past poliomyelitis and compared them with changes described in amyotrophic lateral sclerosis (ALS). Methods : The excitability characteristics of motor and sensory nerves were studied in 10 subjects with stable past poliomyelitis. Results : Motor rheobase was increased, but there were no significant changes in strength–duration properties or depolarizing threshold electrotonus, as have been seen in previous studies of ALS. Conclusions : There is minimal change in axonal excitability properties in patients with stable past poliomyelitis. The results may signify sufficient compensation in the stable state of the disease. Increased subexcitability in 1 subject with demonstrable hyperexcitability may represent compensation for increased ectopic activity rather than a different process in surviving motor neurons. Muscle Nerve 50: 602–604, 2014