Revitalize Cognition: Near Infrared Stimulation in Parkinson Patients

ARENA is a task of spatial memory-navigation that has been linked to hippocampal function and is a human analogue to the Morris water maze, which has shown sensitivity to NIR stimulation in Alzheimer's transgenic mice. ARENA requires participants to learn and navigate to a hidden target location in a simulated environment. It involves use of a joystick over a series of 8 learning trials and one final probe trial. On each learning trial, the path length and time to reach the target are recorded. The Learning dependent variable is a composite score consisting of mean z-scores for path length and for time to reach the target (Learning Composite). A change score is computed by subtracting the baseline Learning Composite from the post-intervention Learning Composite z-score. Higher scores mean a better outcome.

Time frame: Baseline and Post-Intervention (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were evaluated off their normal dose of dopamine medication, following the standard overnight washout period.

ARENA is a computer-based task of spatial memory-navigation that has been linked to hippocampal function and is a human analogue to the Morris water maze. ARENA consists of 9 learning trials and one final probe trial. On each learning trial, the path length and time to reach the target are recorded. On each probe trial, the percent time spent in the spatial quadrant where the target is located is recorded. The dependent variable is a total composite score consisting of mean z-scores for path length, time to reach the target, and %time in the target quadrant during the probe trial (Total Composite). A change score is computed by subtracting the baseline Total Composite z-score from the post-intervention Composite z scores. Higher scores mean better outcome.

Time frame: Baseline and Post-Intervention (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were off their normal dose of dopamine medication, following the standard overnight washout period.

The Fluency Composite is derived from the NIH Examiner, a computer-based battery of executive functioning tasks (Kramer et al., 2014). This composite was chosen due to known verbal fluency difficulties in individuals with Parkinson Disease. Verbal fluency tasks in the NIH Examiner include 2 trials of letter fluency and 2 trials of semantic fluency which are combined to yield a Fluency Composite that ranges from -3.0 to 3.0; higher scores correspond to better fluency performance. A change score is calculated by subtracting the baseline scores from the post-test scores. Greater positive change scores mean better outcome.

Time frame: Baseline and Post-Intervention (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were off their normal dose of dopamine medication, following the standard overnight washout period.

Gait is assessed using the Primary Gait Screen (Schmidt et al., 2019) that requires participants to walk the length of an 8-meter pressure sensitive mat (Zeno Walkway, 120Hz, Zeno Metrics), turn around, and return to the beginning of the walkway. Gait variability during forward walking was selected because in PD, greater variability is associated with increased number of falls and is one of the most disabling symptoms in PD. For this outcome, variability in stride length is indexed by the individual's standard deviation (SD) of stride length measured in centimeters; higher SD scores indicate worse performance. A change score is calculated by subtracting baseline SD of stride length from the post-intervention scores. Negative change scores mean better performance, whereas positive change scores mean worse performance.

Time frame: Baseline and Post-Intervention (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were off their normal dose of dopamine medication, following the standard overnight washout period.

The Negative Affect scale is derived from the emotion module of the NIH Toolbox, a 12-22 minute self-report assessment that surveys current emotion health. The Negative Affect Scale is based on ratings of a series of emotion words. Questions comprise Likert-type items using computerized adaptive testing based on item response theory, resulting in a normed T score (mean of 50, SD of 10). The Negative Affect scale includes items pertaining to fear, anger, sadness. Scores below 40T indicate low levels of negative affect and scores above 60T indicate higher levels of negative affect. A difference score is computed by subtracting the baseline score from the post-intervention score.

Time frame: Baseline and Post-Intervention (2 weeks)

Population: Individuals with idiopathic Parkinson disease who were tested 'off' dopaminergic medications

The RAVLT is a commonly used memory task in clinical settings. It is a 15-item word list learning task given over 5 trials followed by delayed recall of the list 20-30 minutes later. The major outcome is number of items freely recalled after the delay. Scores can range from 0 to 16 (maximum number of words), with higher score reflecting better performance. A change score is calculated by subtracting the baseline score from the post-intervention score. Higher difference scores indicate better performance due to intervention.

Time frame: Baseline and Post (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were off their normal dose of dopamine medication, following the standard overnight washout period.

This Working Memory composite is derived from a computer-based battery of executive functioning tasks (NIH Examiner). This composite was chosen due to known working memory difficulties in individuals with Parkinson disease. The Working Memory composite consists of scores from the N-back task and a Dot Counting task, which are combined to yield a composite score that ranges from -3 to 3.0; higher scores correspond to better working memory. A change score is calculated by subtracting the baseline Working Memory Composite from the post-intervention Working Memory Composite.

Time frame: Baseline and Post (2 weeks)

Population: Participants included nondemented individuals with Parkinson disease who were randomized to active or sham intervention groups. During outcome testing, PD participants were off their normal dose of dopamine medication, following the standard overnight washout period.

Part III of the Unified Parkinson Disease Rating Scale (UPDRS) is a standard clinical rating scale for motor symptoms in individuals with Parkinson disease. It is clinician administered by a trained rater and involves ratings of motor tremors, rigidity, and slowness. In the research setting, the scale is videotaped for later scoring by a trained rater who is blinded to group assignment. The Part III motor scale score ranges from 0 to 108 and involves 27 responses to 14 questions. Higher scores are worse and reflect more severe motor symptoms. A change score is computed by subtracting baseline UPDRS motor score from the post-intervention score. Greater change in negative direction reflects better outcome.

Time frame: Baseline and Post-Intervention

Population: Patients with Parkinson disease who were tested off dopamine medication following standard overnight washout.