Combined STN and NBM Deep Brain Stimulation for Mild Cognitive Impairment in Parkinson's Disease

Any untoward medical occurrence that occurs during this study whether or not considered related to the study device, study procedures, or study requirements that is identified or worsens during the duration of the study

Swing time variability will be measured using the dual force plates in the SIP task and IMUs for TBC. It is defined as the mean swing time coefficient of variation (CV) of both legs.

Duration of freezing episodes during SIP will be measured using IMUs and force plates using a validated offline algorithm.

Stride time coefficient of variation will be measured using the dual force plates in the SIP task and IMUs. Stride time coefficient of variation is defined as the mean stride time coefficient of variation (CV) of both legs. A greater stride time CV is indicative of less rhythmic gait/stepping.

Shank angular velocity will be measured from IMUs work on the participant's leg/ankle. Reductions in this value are indicative of FOG and gait impairment.

The interstrike-interval of alternating tapping will be measured using an engineered piano keyboard. A higher interstrike-interval indicates slower tapping

The variability of the interstrike-interval of alternating tapping, as quantified by the coefficient of variation, will be measured using an engineered piano keyboard. A higher coefficient of variation indicates worse rhythmicity

PD symptoms will be assessed clinically using the MDS-Unified Parkinson's Disease Rating Scale (UPDRS) Section III. This is a motor examination to evaluate speech, facial expression, tremor at rest, action or postural tremor of hands, rigidity, finger taps, hand movements, rapid alternating movement of hands, leg agility, arising from chair, posture, gait, freezing of gait, posture, body bradykinesia, and postural stability. Each item is scored on a scale from 0 (normal) to 4 (severe), with the total possible score ranging from 0 to 132.

Each trial of the SAT will be categorized as a Hit (H), Miss (M), or False Alarm (FA). The SAT score is defined as ((H - FA) / [2× (H + FA) - (H + FA)2]), which ranges from - 1.0 (100% incorrect performance; all misses and false alarms) to +1.0 (100% correct performance; all hits and correct rejections).

The percent of false positives during the SAT.

The percent of misses of total trials during the SAT

The average and standard deviation of the response time during the SAT.

Hit rate during the first minute in the no- distractor condition for the CTET.

Hit rate change slope in no-distractor condition for the CTET.

Hit rate difference between no-distractor and distractor conditions for the CTET.

Cognitive scale composed of 9 tasks that assesses the full range of cognitive dysfunction in PD. It is a scale of 0 to 134, with 134 being the best score.

Total score to assess of this rapid screening test of different cognitive domains. It is a scale of 0 to 30, with 30 being the best score.

The time it takes to complete the task and errors.

The time it takes to complete the task and errors.

The summation of the number of correct substitutions within the 90 second interval.

Percentile of performance on visual puzzles for participant's demographic.

Percentile of performance on judgement of line orientation for participant's demographic.

Total score on questionnaire regarding participant's mood the last 2 weeks. The scale ranges from 0 to 27 with a score of 27 indicating the most severe symptoms.

Total score on questionnaire regarding participant's anxiety the last two weeks.The scale ranges from 0 to 21 with a score of 21 indicating the most severe symptoms.

Total score evaluating the non-motor aspects of experiences of daily living. It is a scale from 0 to 52 with 52 being the most severe symptoms.

Total score evaluating the motor aspects of experiences of daily living. It is a scale from 0 to 52 with 52 being the most severe symptoms.

Total score of motor complications experienced by the participant. It is a scale from 0 to 24 with 24 being the most severe symptoms.

Total score for symptom severity and distress via questionnaire. It is a scale from 0 to 60 with 60 indicating worse symptoms.

Total score for Parkinson's disease-specific health related quality over the last month across 8 quality of life dimensions assessed via questionnaire. Score ranges from 0 to 100 with 100 indicating more symptoms and problems.

Total score on caregiver self-report to assess the stress-levels of family caregivers. It is a scale from 0 to 88 with higher scores indicating greater or worse burden.