Follow up study: The influence of rTMS with high and low frequency stimulation on motor and executive function in...

rTMS may influence on both cognitive and motor function in PD but the daily routine and the predictors of responders to rTMS are not known.

We 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.

A 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 1Hz (N=28), 5Hz (N=13) and 5+1Hz (N=25) frequency at low intensity over each DLPFC and the brain stem for 7days were compared. Patients were followed for six months. UPDRS, the Trail Making Test, and dual tasks were applied. Patients ≤65years >65yrs were compared. Data were analyzed by repeated measure ANOVA.

Only 1Hz 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 >65yrs was observed after one month (p<0.01). Executive function >65yrs (N=16) was significantly worse compared with C (N=15) and it was improved temporarily by 1Hz. Five Hertz and 5+1Hz did not cause improvement.

One Hertz with proper intensity has a good outcome in PD. Patients >65yrs 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.