The demographic foundation behind bias-corrected CCAB scoring.
The CCAB normative dataset comprises over 2,000 community-recruited adults spanning the full adult lifespan, designed to support accurate, bias-corrected cognitive scoring across the demographic diversity of modern clinical and research populations. Data collection has been supported by NIH/NIA SBIR grants and is ongoing, with longitudinal follow-up extending to three years.
Participants range in age from 18 to 89, with a mean age of 52, with strong representation across younger, middle-aged, and older adult groups, supporting normative scoring across the clinical age ranges most relevant to cognitive assessment.
Recruitment was designed to achieve broad demographic representation. The sample includes White, Black, Asian, and participants of other racial backgrounds, with approximately 20% identifying as Latino or Hispanic. The sample is 57% female and 42% male. All tests are available in both English and Spanish.
Educational attainment ranges from no formal schooling through graduate and professional degrees, spanning the full spectrum of backgrounds encountered in clinical practice and enabling normative scores that account for education's substantial influence on cognitive performance.
Each participant completes a structured questionnaire at enrollment and at each follow-up session, capturing variables relevant to cognitive health, daily function, and wellbeing. The battery covers six broad domains, enabling detailed demographic correction and subgroup analyses.
Anxiety GAD-7, depression GDS, cognitive complaints, fatigue
Education, race, ethnicity, marital status, housing
Medications, comorbidities, neurological history
Memory change, cognitive failure frequency
Computer familiarity and daily usage
Reading habits and daily activities
All CCAB tests are administered remotely on a tablet computer and monitored in real time by a trained examiner. Before testing, participants complete an auditory calibration procedure that sets instruction volume individually, and a visual screening test to confirm normal or corrected-to-normal vision.
Remote administration has been validated against in-lab testing in approximately 100 participants, with no significant difference in results. Annual retests are conducted longitudinally, with data collection ongoing.
Because vocabulary is acquired over a lifetime and is relatively resistant to cognitive decline, it serves as a reliable index of pre-morbid intellectual ability, marking the cognitive level a person would have achieved before any decline. Each participant's vocabulary is assessed using an adaptive test that estimates receptive vocabulary level precisely and efficiently.
Vocabulary is incorporated directly into the C-model scoring framework, enabling scores corrected not just for age and education, but for individual differences in pre-morbid ability, substantially reducing demographic bias in cognitive classification.
Adaptive vocabulary level score; mean 34, SD 9.4
Participants are community-recruited adults from the San Francisco Bay Area, recruited through online platforms and community health fairs. Endorsement of any of the following results in exclusion from the normative sample.
Normative data collection supported by NIH/NIA SBIR grants R44AG062076 and R44AG080951.
Normative data are available through the Open Science Framework.
Available on the Open Science Framework