Open Access

M. Muthalib, Muthuraman Muthuraman, G. K. Kerr, L. K. Byrne, R. G. Bittar, G. Deuschl, S. Perrey

• Subthalamic nucleus (STN) deep brain stimulation (DBS) therapy is an effective treatment for the appendicular motor symptoms of Parkinson’s disease (PD). The STN contains multiple segregated circuits subserving motor, cognitive and mood functions through distinct connectivity to cortical regions. Therefore, we examined prefrontal cortical (PFC) effects of “ON” and “OFF” STN-DBS on executive function (Go/NoGo) using functional near-infrared spectroscopy (fNIRS). Methods Out of 8 PD STN-DBS patients, we present here preliminary analysis of a male (62y) PD patient with bilateral STN-DBS (unipolar, 180Hz, 3.5V). The patient was tested after 12h withdrawal of dopamine medications in both an “OFF” and “ON” DBS session separated by 30min. The subject performed a computerised GoNoGo task with 3 alternating Go/NoGo blocks of 30s duration (20 trials/block) interspersed with 30s rest. Reaction time (RT) and accuracy (omission-Om and commission-Cm errors) results were the average of the 3Subthalamic nucleus (STN) deep brain stimulation (DBS) therapy is an effective treatment for the appendicular motor symptoms of Parkinson’s disease (PD). The STN contains multiple segregated circuits subserving motor, cognitive and mood functions through distinct connectivity to cortical regions. Therefore, we examined prefrontal cortical (PFC) effects of “ON” and “OFF” STN-DBS on executive function (Go/NoGo) using functional near-infrared spectroscopy (fNIRS). Methods Out of 8 PD STN-DBS patients, we present here preliminary analysis of a male (62y) PD patient with bilateral STN-DBS (unipolar, 180Hz, 3.5V). The patient was tested after 12h withdrawal of dopamine medications in both an “OFF” and “ON” DBS session separated by 30min. The subject performed a computerised GoNoGo task with 3 alternating Go/NoGo blocks of 30s duration (20 trials/block) interspersed with 30s rest. Reaction time (RT) and accuracy (omission-Om and commission-Cm errors) results were the average of the 3 Go/NoGo blocks. During performance of the Go/NoGo blocks, changes in oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin concentrations were measured by a fNIRS system (Oxymon MkIII, Artinis Medical Systems) covering the bilateral PFC regions. Results/Discussion Clinical motor performance (UPDRSIII) improved from OFF (31) to ON (20). RT during Go and NoGo was ∼40ms faster in OFF (460 and 364ms) than ON (516 and 407ms). Furthermore, the NoGo condition increased misses (Om) in ON (7%) than OFF (0%); while false alarms (Cm) were similarly increased in ON (27%) and OFF (30%). The Go and NoGo conditions increased bilateral PFC activation (i.e., increase in O2Hb and decrease in HHb). However, there was a general decrease in PFC activation in OFF relative to ON, and this was more obvious in Go than NoGo (see Fig. 1) Conclusion These preliminary results indicate that STN-DBS modulates neurovascular responses in the bilateral PFC that are associated with response inhibition.…