Istradefylline for Parkinson Disease With Cognitive Impairment

NIH Toolbox Cognition Battery (NTCB): Scores are reported as T-scores normed to a mean of 50 with a standard deviation (SD) of 10, with higher scores indicating better cognitive functioning. In this dataset, the lowest T-score was 28 and the highest T-score was 66.

Immediate and delayed recall will be assessed using the Hopkins Verbal Learning Test - Revised, which will be administered by a trained clinician. Higher scores indicate better recall. aw metrics must be converted into standard scores because raw totals decrease naturally with normal aging. Examiners utilize the normative data inside the Official PAR HVLT-R Manual Supplement or automated PARiConnect software to convert raw metrics into T-scores. T-scores adjust for age (and sometimes gender and education level depending on the specific norming data used). T-Score Range: Typically spans from 20 to 80. Average Performance: 40 to 59, Borderline/Low Range: 30 to 39, Clinical Impairment: Below 30

In the Controlled Oral Word Association Test (FAS, animals) (COWAT) the participant is asked to make verbal associations to different letters of the alphabet by saying all the words which they can think of beginning with a given letter. Higher scores indicate better oral fluency. Because it is a free-generation task, there is no formal maximum "ceiling" score, but performance typically falls into predictable ranges. Average Performance: Healthy young-to-middle-aged adults typically generate an aggregate total of 35 to 45 words across all three letters combined. Scoring beneath the 25th percentile suggests a low-average performance. If the trajectory drops significantly further-specifically below the 5th percentile (equivalent to ≤ 1.5 standard deviations under the median)-clinicians look closely for signs of mild cognitive impairment (MCI), aphasia, or neurodegenerative conditions.

TMT which is a timed test of attention and executive function.It primarily assesses visual scanning, attention, and processing speed and requires participants to connect numbered targets in sequential order. It additionally assesses cognitive flexibility and executive function and requires participants to alternate between numbers and letters in sequential order. Raw scores are the number of seconds needed to complete the test with higher scores indicating poorer executive function. A standard cutoff or cap is typically applied at 300 seconds (5 minutes) per section to halt the test if a patient struggles. The raw scores are converted into T-scores based on Heaton norms for age, sex, race, and education. T-scores have a mean of 50 and standard deviation (SD) of 10, with higher T-scores indicating better performance. T-scores ≥40 are generally considered within normal limits, while T-scores <40 indicate below-expected performance, with lower scores reflecting greater impai

Participant's cognitive status will be assessed using the Montreal Cognitive Assessment score. Higher scores indicated better cognitive status. The Montreal Cognitive Assessment (MoCA) is scored between 0 and out of a maximum of 30 points, with a raw total score of 26 or above traditionally considered clinically normal. 18-25 points is considered Mild Cognitive Impairment (MCI), 10-17 points is considered Moderate Cognitive Impairment, and less than 10 is considered Severe Cognitive Impairment

The Dementia Rating Scale-2 (DRS-2) measures deficits in a large range of higher cortical functions and differentiates deficits of varying severity levels. The Dementia Rating Scale-2 (DRS-2) is scored out of a maximum of 144 total raw points. A higher score indicates better cognitive function, while lower scores signify greater cognitive and behavioral impairment. 124-144 points indicated Normal/non-impaired, 120-123 Borderline/mild, less than 120 points Impaired. The maximum possible total score for the Dementia Rating Scale-2 (DRS-2) is 144, and the minimum possible total score is 0. There are five domains that equal 144 points. Each domain has a different maximum score, but they all have a minimum score of 0: Attention: Maximum score of 37, Initiation/Perseveration: Maximum score of 37, Construction: Maximum score of 6, Conceptualization: Maximum score of 39, Memory: Maximum score of 25.