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The Number Symbol Coding Task: A brief measure of executive function to detect dementia and cognitive impairment
James E Galvin1, Magdalena I Tolea1, Claudia Moore1
1Department of Neurology, Comprehensive Center for Brain Health, University of Miami Miller School of Medicine, Miami, Florida, United States of America.
Plos One
|November 30, 2020
Summary
The Number Symbol Coding Task (NSCT) is a brief, 90-second executive function test that effectively detects cognitive impairment in Alzheimer's disease and related dementias (ADRD). It shows strong correlations with established measures and can aid in early diagnosis and research.
Area of Science:
- Neurology
- Cognitive Science
- Geriatrics
Background:
- Alzheimer's disease and related dementias (ADRD) impact millions globally, with early detection of mild cognitive impairment (MCI) and ADRD posing significant clinical challenges.
- Executive dysfunction, rather than memory impairment, may be an early indicator of cognitive decline.
- Existing brief assessment tools often focus on memory, necessitating a dedicated, accessible measure for executive function.
Purpose of the Study:
- To introduce and validate the Number Symbol Coding Task (NSCT), a novel, brief, open-access test designed to assess executive function.
- To evaluate the psychometric properties and clinical utility of the NSCT for detecting cognitive impairment in diverse populations.
Main Methods:
- Analysis of 320 patient-caregiver dyads undergoing comprehensive dementia evaluations, including the Clinical Dementia Rating (CDR) and Quick Dementia Rating System (QDRS).
- Calculation of cognitive reserve using education, occupation indices, and verbal IQ.
- Determination of NSCT's psychometric properties: data quality, distribution, floor/ceiling effects, validity, discriminability, and clinical profiles.
Main Results:
- The NSCT demonstrated a normal distribution and was completed by all healthy controls and MCI cases.
- NSCT scores correlated significantly with measures of executive function (p < .001), cognitive status, and caregiver ratings.
- The NSCT showed excellent discrimination (AUC: .866), with a cutoff score of 36 offering optimal sensitivity and specificity; combining with QDRS improved discrimination (AUC: .908).
Conclusions:
- The NSCT is a brief (90-second) executive function task assessing attention, planning, and set-switching, suitable for individuals up to moderate-to-severe dementia stages.
- The NSCT is a valuable tool for dementia screening, epidemiological studies, and primary care settings due to its brevity and ease of use.
- Combining the NSCT with structured interviews like the QDRS enhances the detection of cognitive impairment, facilitating clinical care and research.
