Shin-ichi Tsunoda

Increased sympathetic outflow to muscles in patients with amyotrophic lateral sclerosis: a comparison with other neuromuscular patients

We investigated the effects of muscle loss and limitation of daily activities on sympathetic outflow to muscles by measuring muscle sympathetic nerve activity (MSNA) in 12 patients with amyotrophic lateral sclerosis (ALS) as compared with other 15 neuromuscular patients (controls). The burst incidence of MSNA at rest was significantly higher in patients with ALS, even in elderly patients, compared with controls (p < 0.01). There were no differences in the level of disability, heart rate or blood pressure at rest between two groups. Blood pressure and MSNA were less changed by head-up tilting in patients with ALS compared with controls. MSNA of ALS was not correlated with the disability score, PaO2, PaCO2, forced vital capacity, the disease duration or prognosis. MSNA at rest was increased in ALS patients, regardless of the severity of muscle loss or disability. It might be suggested that autonomic motor neurons seem to become affected by the same pathologic process that kills motor neurons.

Microneurographic analysis of muscle sympathetic nerve activity in amyotrophic lateral sclerosis

Muscle sympathetic nerve activity by (microneurograph) blood pressure and heart rate has been studied in patients with amyotrophic lateral sclerosis and in age-matched normal subjects (controls) at rest and during head-up tilt. Muscle sympathetic nerve activity in amyotrophic lateral sclerosis patients was significantly increased at rest unlike controls. There was no correlation between muscle sympathetic nerve activity and age in the patients with amyotrophic lateral sclerosis. Elevated muscle sympathetic nerve activity was present mainly in younger patients. There were no differences between blood pressure or heart rate in either group at rest or during head-up tilt in amyotrophic lateral sclerosis. The increase in muscle sympathetic nerve activity following tilt in the amyotrophic lateral sclerosis patients was less than in the controls, but they had no postural hypotension. The possible reasons for this observation of increased muscle sympathetic nerve activity at rest in amyotrophic lateral sclerosis are discussed.

Paroxysmal choreoathetosis precipitated by movement, sound and photic stimulation in a case of arterio-venous malformation in the parietal lobe

A patient is presented with paroxysmal choreoathetosis precipitated by movement, sound and photic stimulation associated with an arterio-venous malformation (AVM) who responded to carbamazepine treatment. Hemodynamic circulatory disorder of the sensory-motor cortices having AVM may alter striatal function and produce paroxysmal choreoathetosis. This finding supports the concept that paroxysmal choreoathetosis results from an abnormality at the connections between basal ganglia and cerebral cortices.

Comparison between muscle sympathetic nerve activity and calf vascular resistance with head-up tilting in humans

The purpose of this study was to determine the relationship between muscle sympathetic nerve activity (MSA) to calf muscle and calf vascular resistance with head-up tilting in humans. In nine healthy volunteers, we performed simultaneous measurements of MSA using microneurography and calf vascular resistance using electrical impedance plethysmography in the same leg. The volunteers were laid on a tilt table and the examinations with head-up tilting (0 degrees, 30 degrees, 60 degrees) were performed. Corresponding to the increase in angles of head-up tilting, MSA and calf vascular resistance significantly increased. A statistically significant positive linear correlation was demonstrated between MSA and calf vascular resistance. These data suggest that impedance plethysmographic measurement of calf vascular resistance can be reliably used to assess the status of MSA with head-up tilting.

A comparison of sympathetic outflow to muscles between cervical spondylotic amyotrophy and ALS.

To confirm the diagnostic usefulness of muscle sympathetic nerve activity (MSNA) in differentiation between cervical spondylotic amyotrophy (CSA) and amyotrophic lateral sclerosis (ALS) with cervical spondylosis (CS), MSNA, heart rate (HR) and blood pressure (BP) were recorded in 10 patients with CSA and ALS with CS, and age-matched healthy volunteers at rest and during head-up tilting. There were no differences in age, disability scores, pulmonary function, and HR or BP at rest between ALS and CSA groups. Resting MSNA was significantly greater in patients with ALS with CS than in comparison groups (P<0.001) with virtually no overlap between ALS and the CSA groups. During head-up tilting, changes in BP and MSNA were significantly less in patients with ALS than in patients with other subjects. MSNA at rest clearly differentiated CSA from ALS with CS, suggesting diagnostic utility.

Muscle spasm induced sympathetic reflex bursts on microneurography in a case with pontine demyelination

Microneurography was performed in a 39-year-old woman with demyelination of the pontine white matter associated with muscle spasms in the lower extremities. Single bursts on the microneurogram were observed immediately after cessation of the spasm with no systemic changes in the blood pressure or heart rate. Voluntary tonic flexion of the lower extremities induced similar bursts with small amplitudes. These reflex bursts possessed a characteristic of muscle sympathetic nerve activity, because the latency between the peak of each burst and the prior R-wave on the electrocardiograph was constant. The occurrence of these bursts suggests that a segmental compensatory mechanism in the spinal cord may stabilize the muscle blood flow influenced by muscle contraction.