Research reportFollow up study: The influence of rTMS with high and low frequency stimulation on motor and executive function in Parkinson's disease

- The study confirms the relationship between the intensity and the frequency of rTMS.
- One Hz is connected with low intensity, which can improve the outcome of PD.
- No effect of 5 Hz and 5 + 1 Hz with low intensity can be observed.
- There was a strong age dependency in the effect of rTMS.
- The motor ability ≤65 yrs and the executive function >65 yrs can be influenced.

BackgroundrTMS may influence on both cognitive and motor function in PD but the daily routine and the predictors of responders to rTMS are not known.Objective/hypothesisWe hypothesized that the frequency and intensity of stimulation somehow relate to each other. Our goal was to select the optimal frequency with low intensity for PD. We clarified the importance of age in the effect of rTMS.MethodsA total sixty-six patients with PD were included in the study. In an open investigation, randomly selected patients were divided into three groups. The effects of 1 Hz (N = 28), 5 Hz (N = 13) and 5 + 1 Hz (N = 25) frequency at low intensity over each DLPFC and the brain stem for 7 days were compared. Patients were followed for six months. UPDRS, the Trail Making Test, and dual tasks were applied. Patients ≤65 years >65 yrs were compared. Data were analyzed by repeated measure ANOVA.ResultsOnly 1 Hz had an effect on motor scores. Before the trial patients ≤ 65 yrs had UPDRS total scores of 30.3 ± 16.9, after 1 month: 17.8 ± 8.9 p < 0.001, after 6 months 18.3 ± 8.8 p < 0.001. Improvement of patients >65 yrs was observed after one month (p < 0.01). Executive function >65 yrs (N = 16) was significantly worse compared with C (N = 15) and it was improved temporarily by 1 Hz. Five Hertz and 5 + 1 Hz did not cause improvement.ConclusionOne Hertz with proper intensity has a good outcome in PD. Patients >65 yrs show deterioration in their executive function and they have shorter duration in their therapeutic effect of rTMS. This study draws attention to the importance of stimulation intensity and age as a predictor of the effect of rTMS.