P300 Influence of rTMS with high and low frequency stimulation on motor and executive function in Parkinson’s disease. Follow-up study for half year

Abstract

The non-invasive brain stimulation, like transcranial magnetic stimulation (rTMS) can influence on both cognitive and motor function of Parkinson’s disease (PD). However, a protocol for daily routine is not yet been known. Furthermore, there are not known the predictors of responders or not responders to rTMS treatment. Our main goal was to select the optimal frequency with low intensity for improving executive and motor function in PD. Furthermore, we clarified the importance of age. Three groups of patients with PD were compared with each other and healthy controls in the mental tests. The 1 Hz (N = 28), 5 Hz (N = 13) and 5 + 1 Hz (N = 19) frequency with low intensity was applied daily over both dorsolateral prefrontal cortices (DLPFC) and over the brain stem for 7 days. Patients were followed for six months after the treatment with rTMS. The participants were divided into two groups according to their age (⩽ 65 years and 65 years >). The patients were tested with UPDRS, walking for 6 min, 10 m walk, Trail Making Test, and dual tasks. Only the 1 Hz treatment with low intensity for 7 days had an effect on the motor scores. The rTMS with 1 Hz caused significant improvement in the motor symptoms assessed by UPDRS after one month (before trial (BF) ⩽ 65 UPDRS total score 32.0 ± 15.0 3, after 1 month: 18.1 ± 8.6 p 0.001 , >65 BF: 28.5 ± 15.8, after 1 month: 18.6 ± 10.3 p 0.05 and it was maintained for six months in the group with ⩽ 65 yrs (N = 10, 18.2 ± 8.8 p 0.001 ). However, in the group with >65 yrs (N = 16) the better outcome was observed only after one month (BF: 28.5 ± 15.8, 1 month later 18.6 ± 10.3 p 0.01 , after 6 months: UPDRS total score: 20.8 ± 12.7 p = 0.06). Although, the stimulation with 5 + 1 Hz decrease scores assessed by UPDRS, but neither the stimulation with 5 Hz nor with 5 + 1 Hz with low intensity caused significant changes in PD. Results of Trail Making Test and dual tests in PD ⩽ 65 yrs did not differ from controls (C) below 65 years. However, the executive function of patients over 65 yrs (N = 16) were significantly worse compared to controls (N = 15) (C: Trail B-A: 50.0 ± 25.1 s, PD: Trail B-A > 65 yrs: 76.0 ± 45.1 s p 0.01 ). Six months after treatment with rTMS with 1 Hz an improvement was observed in Trail Making Test compared to onset of treatment (PD: 48.70 ± 21.4 s p 0.05 ). The dual test was deteriorated in the group over 65 years compared to age match controls. The 1 Hz stimulation did not reverse their values. (C: counting back (CB) −3: 50.0 ± 25.9 s, >65 yrs PD CB −3: 57 ± 21, 1 month after rTMS CB −3: 69 ± 20, 6 months after rTMS: 60 ± 19 s; PD BF CB-7 100 ± 45 s, 1 month 102 ± 32 s, 6 months: 82 ± 23 s). Stimulation with rTMS in the group >65 yrs showed shorter effect in motor scores than in the younger age group. Patients over 65 years in PD caused a significant deterioration in the executive function compared with age matched healthy controls. It was influenced temporarily by 1 Hz low intensity stimulation. Both the low and high frequency stimulation with proper intensity may have good outcomes in neurological diseases. Patients over 65 yrs with PD may deteriorate in their executive function compared with age matched healthy controls and decreases in the therapeutic effect of rTMS on motor function.