[Sympathetic neurograms in patients with neurodegenerative disorders--an overview]

Sympathetic nerve functions in patients with amyotrophic lateral sclerosis (ALS), spinocerebellar degeneration (SCD), and Parkinson disease (PD) were evaluated using microneurography. In patients with ALS, the muscle sympathetic nerve activity (MSNA) at rest was greater than that in healthy subjects and patients with other neuromuscular disorders. This finding is not observed in the advanced stages of ALS. The resting frequency of skin sympathetic nerve activity (SSNA) significantly greater in ALS patients than in healthy controls. In patients with SCD, the MSNA was slightly reduced, although these patients did not experience orthostatic dizziness or syncope, or significant fall in blood pressure during the head-up tilt test. The reflex latency of SSNA induced by electric stimulation was slightly but significantly prolonged in patients with cortical cerebellar atrophy and markedly prolonged in patients with multiple system atrophy-C (MSA-C). In patients with PD, a significantly negative correlation was observed between MSNA and age, and between MSNA and disease duration. In these patients, the resting frequency of SSNA was significantly lower than in healthy controls, while SSNA reflex latencies were similar to those in the controls. Further investigations to determine whether the autonomic nervous system was impaired are imperative for elucidating the pathogenesis of neurodegenerative disorders.