Pre-DBS modified Tremor/Postural instability and gait difficulty score ratio as indicator of short-term outcome of subthalamic nucleus DBS in Parkinson's disease

Purpose: The outcomes of motor and non-motor features of Parkinson's disease (PD) following DBS vary among its subtypes. We tested whether pre-operative motor subtyping using the modified Tremor/PIGD ratio, could indicate the short-term motor, non-motor and quality of life (QOL) outcomes of STN-DBS.

Method: In this prospective study, 39 consecutive STN-DBS cases were assessed in Drug-OFF state before surgery and subtyped using the ratio of tremor and PIGD scores (T/P ratio). 6 months after surgery patients were reassessed in Stimulation ON-Drug OFF state and the percentage change in motor, non-motor and QOL scores (PDQ39) was calculated.

Results: The modified T/P ratio had a moderate, positive correlation with the percentage change in scores of UPDRS III in OFF, sum of cardinal motor signs, non-motor symptoms scale (NMSS) and quality of life (PDQ39).

Conclusion: Preoperative PD motor subtyping can be used as an indicator of the short-term, outcomes of STN-DBS in PD.