Over 15 years, poliomyelitis survivors showed declines in CMAP and MUNE, with symptoms of late deterioration associated with residual deficits rather than the magnitude of decline.
Cohort
In polio survivors, summated MUNE is a more sensitive measure of motor unit loss than summated CMAP, and neuron loss follows a proportional rather than linear pattern over time.
A population-based cohort of poliomyelitis survivors was established and followed for 15 years (mean time since polio was 40 years). Over time, the cohort demonstrated a modest decline in summated compound muscle action potential amplitudes (CMAP) and a moderate decline in the summated motor unit number estimates (MUNE). There was no association between symptoms of late deterioration and magnitude of decline. Rather, the presence of these symptoms was associated with the magnitude of the residual deficits. Two patterns of neuron loss were modeled (linear and proportional decline). The summated MUNE was a more sensitive measure of loss of motor units than was the summated CMAP and appears to be a more valid measure of attritional loss of anterior horn cells. Of these two models of neuron loss, the proportional loss of motor neurons was a better fit of the data than a linear loss.
Sorenson et al. (Thu,) conducted a cohort in Poliomyelitis survivors. Time was evaluated on Summated compound muscle action potential amplitudes (CMAP) and summated motor unit number estimates (MUNE). Over 15 years, poliomyelitis survivors showed declines in CMAP and MUNE, with symptoms of late deterioration associated with residual deficits rather than the magnitude of decline.