Identification of the laterality of motor unit behavior in female patients with parkinson's disease using high‐density surface electromyography

Abstract

Patients with Parkinson's disease (PD) have greater laterality of muscle contraction properties than other people with parkinsonism diseases. However, few studies have reported the laterality of MU activation properties of the lower extremity muscles in patients with PD. The aim of the present study was to identify the laterality of MU behavior in PD patients using high-density surface electromyography (HD

Association between the Degree of Pre-Synaptic Dopaminergic Pathway Degeneration and Motor Unit Firing Behavior in Parkinson’s Disease Patients

“…The more-affected side showed a lower knee extensor torque, recruitment threshold, and SBR Bolt , and a higher CV of the mean MU firing rate than the less-affected side. Previous studies have reported that people with PD exhibit laterality in muscle strength, abnormal MU firing behavior, and degeneration of the central nervous system [ 11 , 26 ]. These previous findings are in accordance with the results of this study showing that compared with the less-affected side, the more-affected side exhibited less muscle strength, larger abnormalities in MU firing behavior, and more severe degeneration of the central lesion.…”

“…A previous study reported that people with PD showed a possible shift in the MU population to a lower recruitment threshold than healthy control subjects. Furthermore, our previous report showed that there was a significant correlation between the mean MU firing rate and recruitment threshold on the less-affected side but not on the more-affected side [ 11 ]. MU firing behavior is primarily determined by the excitatory input of synapses from the corticospinal tract to the motor neuron pool [ 29 ].…”

“…Associations between the UPDRS Part III scores and SBR Bolt and between the SBR Bolt and mean MU firing rate, CV of the mean MU firing rate, cross-correlation function, and linear regression slope were analyzed by using Pearson correlation coefficients. The correlation coefficients were qualitatively interpreted using the following threshold according to a previous study: 0.2–0.4 indicates small; 0.4–0.7 indicates moderate; 0.7–0.9 indicates strong; and 0.9–1.0 indicates very strong [ 11 ]. Tossici-Bolt et al reported that a cutoff SBR of ~ 4.5 distinguished normal and abnormal groups with a sensitivity, specificity, and diagnostic concordance of 97%, 92%, and 95%, respectively [ 25 ].…”

“…Recently, noninvasive methods (high-density surface electromyography (HD-SEMG)) of analyzing motor units (MUs) have been developed [ 5 , 6 , 7 , 8 ], and research has been conducted on abnormalities in MU firing behavior in people with PD [ 9 , 10 , 11 ]. A previous study reported a correlation between clinical measures of the severity of PD and MU firing behavior [ 11 ], and it is plausible that this correlation can be used to evaluate disease severity. However, no studies have examined the association of the degree of neurodegeneration and abnormalities in MU firing behavior in people with PD.…”

“…Previous studies suggest that MU firing behavior could be used to predict central nervous system degeneration. Our previous study showed that abnormal MU firing behavior can be detected even in people with mild symptoms (disease duration = 2.7 ± 0.9 years, Unified Parkinson’s disease rating scale (UPDRS) Part III = 13 (9–16), median (min–max)) with respect to MU firing behavior in healthy subjects [ 11 ]. Notably, even though the people with PD in the present study were independent in their activities of daily living, the HD-SEMG method was able to detect clear differences between PD and healthy subjects [ 11 ].…”