Evaluation of the effect of low-intensity rhythmic transcranial magnetic stimulation on motor and non-motor manifestations of Parkinson's disease

BACKGROUND: The use of repetitive transcranial magnetic stimulation as a method of non-drug therapy of Parkinson's disease has been actively studied over the past decades. The prevailing number of repetitive transcranial magnetic stimulation protocols in Parkinson's disease use a high intensity of stimulation (80–120% of the value of the threshold of the evoked motor threshold from the muscles of the hand), while the choice of the stimulation intensity parameter was carried out empirically.

AIM: to study the effectiveness of low-intensity unilateral repetitive transcranial magnetic stimulation on motor and non-motor symptoms of Parkinson's disease.

MATERIAL AND METHODS:An open prospective non-randomized clinical trial included 37 patients with stage I–III Parkinson's disease according to Hoehn–Yahr (1967), akinetic-rigid and mixed (akinetic-rigid-tremor) forms. All patients underwent repetitive transcranial magnetic stimulation according to the protocol: M1 stimulation zone, frequency 5 Hz, intensity 40% of the cortical motor threshold, on 6s, off 8s, total number of pulses per session 3000. The course of treatment is 10 procedures with 2 days (weekend) off.

RESULTS: All patients completed the study in accordance with the protocol. When analyzing the results of the UPDRS scale (Unified Parkinson's disease rating scale), positive dynamics was noted in all parts of the questionnaire: part I ― from 2 (0; 3) to 0 (0; 1) points, p <0.05; part II ― from 9 (5.5; 12.5) to 4 (2; 6.5) points, p <0.05; part III ― with 11 (7; 14.5) to 6 (2; 7.5) points, p <0.05; part IV (Schwab and England scale) ― from 80% (70; 95) to 90% (85; 100), p <0.05. There was also a selective effect on non-motor symptoms.

CONCLUSION: Low-intensity exposure (40% of the motor threshold) has a significant clinical effect on motor and non-motor symptoms of Parkinson's disease; stimulation of the primary motor cortex can have an antidepressant effect; repetitive transcranial magnetic stimulation has a selective effect on non-motor symptoms of Parkinson's disease: a predominant effect has been demonstrated with respect to olfactory, emotional, cognitive disorders, sleep disorders and hypersalivation; when assessing the dynamics of motor disorders, a more pronounced effect was noted with respect to rigidity, postural disorders, walking speed, and to a lesser extent, the effect on tremor was noted.