Sympathetic sudomotor neural function in amyotrophic lateral sclerosis

Abstract

In patients with amyotrophic lateral sclerosis (ALS), sudomotor and vasomotor function have been considered to be impaired based on sympathetic skin response (SSR) or cutaneous blood flow measurements. We evaluated sympathetic sudomotor and vasoconstrictive neural function in ALS. We simultaneously recorded SSR, skin blood flow, and skin sympathetic nerve activity (SSNA) by microneurography in 20 patients with sporadic ALS and 20 healthy controls. Resting frequency of SSNA was significantly higher in ALS patients than in controls (p <0.05), but the increase of SSNA associated with mental arithmetic was smaller in ALS patients than controls (p <0.05). ALS patients also exhibited slight prolongation of SSNA reflex latencies compared with controls (p <0.05). In conclusion, sympathetic hyperactivity was observed in relation to sudomotor and vasoconstrictive skin responses. Since SSNA reflex latencies reflect central sympathetic function, the central autonomic pathways may be slightly impaired in patients with ALS.

Non‐motor manifestations in ALS patients with tracheostomy and invasive ventilation

“…If the tone of the sympathetic nervous system was constantly elevated, peripheral vascular resistance would be increased, blood flow responses in the skin and muscle would be decreased, and skin temperature would be reduced . Abnormalities in sweating or skin sympathetic nerve activity, which have been reported previously in ALS, may be consistent with the hypothermia observed in our patients …”

Non‐motor involvement in amyotrophic lateral sclerosis: new insight from nerve and vessel analysis in skin biopsy

“…Autonomic involvement has been described in ALS patients . A recent retrospective study found autonomic symptoms in one third of 132 ALS patients.…”

Microneurographic recording from unmyelinated nerve fibers in neurological disorders: An update

“…Similar results were also found by Nygren and Fagius (2011) who reported that elevated resting MSNA responded more weakly to maneuvers in ALS patients compared to controls. Furthermore, sympathetic sudomotor and vasoconstrictive neural activities were recently shown to be abnormal in ALS with resting frequency of SSNA significantly higher than controls but with a smaller increase during the mental arithmetic test (Shindo et al, 2011). ALS patients also exhibited a slight prolongation of SSNA reflex latencies (Shindo et al, 2011).…”

“…Furthermore, sympathetic sudomotor and vasoconstrictive neural activities were recently shown to be abnormal in ALS with resting frequency of SSNA significantly higher than controls but with a smaller increase during the mental arithmetic test (Shindo et al, 2011). ALS patients also exhibited a slight prolongation of SSNA reflex latencies (Shindo et al, 2011). Taken together, these data supported abnormal sympathetic activity in ALS mainly showing resting hyperactivity possibly related to central autonomic pathway impairments as suggested by a mouse ALS model (Kandinov et al, 2013) although peripheral small nerve fiber involvement was also reported in ALS (Weis et al, 2011).…”