CALM

CALM is a transdiagnostic cohort study of children who struggle with attention, learning or memory, run from 2014 to 2022 at the MRC Cognition and Brain Sciences Unit in Cambridge. Children were referred by teachers, clinicians and speech and language therapists regardless of any diagnosis, and a comparison group came from the same schools. The CALM:Open portal shares the clinical, cognitive, questionnaire and MRI data for research on how neurodevelopmental difficulties relate to cognition and brain structure and function.

Composition

The first release (CALM 800) holds 805 referred children aged 5 to 18, each seen once; 345 of them had an MRI session. The second release (CALM 200) adds 187 children from the same schools who were not referred and not screened for any condition; 95 of them were scanned. Together this gives 440 children with MRI. Inclusion required English as the first language, no uncorrected hearing or vision problems and no known neurological condition that explains the difficulties. Alongside imaging come a large cognitive battery, parent questionnaires on behaviour and mental health, referral reasons and reported diagnoses, sex, age and an area deprivation index. Longitudinal follow-up data are planned for a third release; genetic data will not be shared.

Acquisition

Scanning was optional and usually took place within six months of the cognitive assessment, after practice in a mock scanner. All MRI was acquired on a 3T Siemens Prisma with a 32-channel head coil in a session of about 30 minutes: 1 mm MPRAGE T1w, SPACE T2w with thick slices, diffusion with 64 directions at b = 1000 s/mm² and eyes-closed resting-state EPI fMRI with 270 volumes. Imaging is distributed in BIDS.

Annotations

There are no image labels. Phenotypes come from standardised tests and parent ratings, and referral diagnoses were reported by the referrer rather than confirmed by the study.

Known limitations

• Fewer than half of the children were scanned, and the scanned group is self-selected.
• Counts per contrast and the age and sex breakdown of the scanned children are not published.
• The CALM website gives different headline numbers (863 children assessed, 367 scanned) than the portal release description used here.
• Access requires an approved application and is limited to non-commercial research at academic or clinical institutions.