Figure 7.

Clinical correlations with inhibition of neuronal activity in STN. The difference in pre-post OFF drug mUPDRS subscores (depicting clinical improvement) was correlated with the silent period after the 100 Hz stimulation train (A), and the frequency at which the firing rate in STN was reduced by 50% (IF50) (B) for each patient. (A) We found a trend for patients with longer STN silent period values after 100 Hz stimulation to be those that obtained greater clinical improvement from DBS (R² = 0.20, P = 0.08). (B) Those with lower IF50 values (i.e. more sensitive to stimulation frequency) were not significantly associated with better clinical improvement with DBS (R² = 0.15, P = 0.13).