Nerve Conduction Studies in Multiple System Atrophy

Abstract

To study the frequency and severity of peripheral neuropathy in multiple system atrophy (MSA), we performed nerve conduction studies in 42 MSA patients suffering from either cerebellar MSA (MSA-C) or parkinsonian MSA (MSA-P). Abnormal nerve conduction was present in 24% of the patients. Abnormalities were significantly more frequent in MSA-P (43%) compared to MSA-C (14%). Motor nerve conduction velocities were reduced in 4% of the MSA-C and in 7% of the MSA-P patients. Abnormal compound muscle action potentials were more frequent in MSA-P (29% versus 7% in MSA-C) pointing to a more pronounced loss of motor axons in this subgroup. Sensory nerve conduction velocities were abnormal in 4% of the MSA-C and 14% of the MSA-P patients, and mean sensory nerve action potentials were normal in all MSA-C and reduced in 7% of the MSA-P patients. The data provide evidence that the peripheral nervous system is differentially affected in MSA-C and MSA-P.

Is peripheral neuron degeneration involved in multiple system atrophy? A clinical and electrophysiological study

“…Until now, peripheral neurodegeneration in MSA has not been clearly confirmed and explicitly described. In our study, electrophysiological signs of neuropathy (involvement of two nerves) were diagnosed in about 20% of patients with MSA, which seems to be a similar percentage compared to the previous studies [13]. Gallassi et al described two MSA patients with autonomic signs who showed motor nerve conduction slowing suggesting a demyelination component.…”

“…Clinical data on EMG and peripheral studies in MSA are scarce [10,13]. Until now, peripheral neurodegeneration in MSA has not been clearly confirmed and explicitly described.…”

“…Only a few patients with predominant clinical signs of neuropathy confirmed by electrophysiological studies were described so far [11,12]. In a larger study by Abele et al, abnormal nerve conduction was found in 24% of MSA patients, more frequently in MSA-P [13]. Peripheral neuron degeneration has not been yet clearly confirmed and explicitly described in MSA.…”

Peripheral nerve involvement and severity of motor disorder in Parkinson\'s disease: a correlational study

“…According to Braak et al, the neurodegenerative process in Parkinson's disease also affects other CNS structures than those contained in the corticostriatal, nigrostriatal or olivonigral systems 1-4. Other studies published several years ago suggest that in a relatively high percentage of patients suffering from neurodegenerative diseases, both the cortex and peripheral nerve system are affected. 1,5,6,7 Parkinson's disease is where this involvement is most frequently documented.…”

Is peripheral neuropathy a feature of multiple system atrophy?

“…Between 10 and 40% of patients with clinically diagnosed MSA have peripheral neuropathy based on nerve conduction studies and electromyography [1,2], the parkinsonian variant (MSA-P) being more frequently affected than those with cerebellar presentation (MSA-C). The relative involvement of peripheral somatic versus autonomic fibers in MSA has not been investigated in large cohorts.…”