Sex differences in Parkinson's disease: A transcranial magnetic stimulation study

Abstract

Background Demographic and clinical studies imply that female sex may be protective for PD, but pathophysiological evidence to support these observations is missing. In early PD, functional changes may be detected in primary motor cortex using transcranial magnetic stimulation. Objective We hypothesised that if pathophysiology differs between sexes in PD, this will be reflected in differences of motor cortex measurements. Methods Forty‐one newly diagnosed PD patients (22 males, 19 females) were clinically assessed using MDS‐UPDRS part III, and various measures of cortical excitability and sensorimotor cortex plasticity were measured over both hemispheres, corresponding to the less and more affected side, using transcranial magnetic stimulation. Twenty‐three healthy (10 men, 13 women) participants were studied for comparison. Results Among patients, no significant differences between sexes were found in age, age of diagnosis, symptom duration, and total or lateralized motor score. However, male patients had disturbed interhemispheric balance of motor thresholds, caused by decreased resting and active motor thresholds in the more affected hemisphere. Short interval intracortical inhibition was more effective in female compared to male patients in both hemispheres. Female patients had a preserved physiological focal response to sensorimotor plasticity protocol, whereas male patients showed an abnormal spread of the protocol effect. Conclusion The study provides one of the first neurophysiological evidences of sex differences in early PD. Female patients have a more favorable profile of transcranial magnetic stimulation measures, possibly reflecting a more successful cortical compensation or delayed maladaptive changes in the sensorimotor cortex. © 2019 International Parkinson and Movement Disorder Society

Transcranial random noise stimulation over the primary motor cortex in PD-MCI patients: a crossover, randomized, sham-controlled study

“…Indeed, the abnormal excitability of intracortical circuits have been found in subjects with PD (even if not in all reports) with evidence of reduced intracortical inhibition and increased intracortical facilitation (Ni et al 2013;Shirota et al 2019). Other abnormalities of cortical excitability in PD concerning gender (Kolmancic et al 2019) and asymmetry of motor involvement have also been reported, particularly in early PD patients, with an interhemispheric imbalance of excitability, and abnormal transcallosal inhibition (Spagnolo et al 2013).…”

Sex Differences in Patterns of Sleep Disorders Among Hospitalizations With Parkinson’s Disease: 2004–2014 Nationwide Inpatient Sample

“…It has been established that women are more likely than men to experience sleep disturbances especially after menopause, with 35% to 60% of postmenopausal women reporting significant sleep disturbance (18). Sex differences in PD have also been established whereby higher prevalence and earlier age at onset are frequently observed in men (19)(20)(21)(22)(23)(24)(25). Furthermore, limited evidence has suggested that women with PD experience more sleep disturbances than men, although biological mechanisms for these sex differences are less well understood (7).…”

Diagnostic value of motor evoked potential parameters in patients with Parkinson’s disease stage II

“…It is known that patients with PD have a wide range of disorders of neurophysiological parameters in the primary motor cortex, which are correlated in direct proportion to the severity of clinical motor symptoms of PD [2,8]. Neurophysiological parameters of the central nervous system (CNS) can be assessed using transcranial magnetic stimulation (TMS) [4,10].…”

“…Neurophysiological parameters of the central nervous system (CNS) can be assessed using transcranial magnetic stimulation (TMS) [4,10]. The method of diagnostic TMS makes it possible to assess the excitability of the nervous system using the parameters of motor evoked potential (MEP), which include latency, amplitude and duration [8].…”

“…The presence of oligobradykinesia, muscle rigidity and rest tremor significantly impairs the quality of life of patients with PD. It is a proven fact that dopaminergic therapy improves the motor activity of patients with PD and has a positive effect on neurophysiological parameters [2,8].…”