Assessment & Research

Neurobehavioural Patterns in the Diagnosis of Autism Spectrum Disorder in Down Syndrome.

Patel et al. (2025) · Journal of intellectual disability research : JIDR 2025
★ The Verdict

A 30-item parent checklist spots true autism inside Down syndrome without crying wolf.

✓ Read this if BCBAs doing intakes in developmental clinics or schools serving kids with Down syndrome.
✗ Skip if Practitioners working only with high-IQ verbal clients.

01Research in Context

01

What this study did

Researchers built a 30-item parent form called ND-PROM. It asks about play, routines, and social quirks.

They gave it to three groups: Down syndrome only, ASD only, and kids with both. Parents filled it out online.

02

What they found

ND-PROM scores cleanly split the groups. Items about odd toy use and strict routines flagged ASD.

Kids with Down syndrome plus ASD scored higher than Down-only peers. No overlap in the key items.

03

How this fits with other research

Scahill et al. (2015) warn that most ASD checklists lump repetitive behaviors together. ND-PROM breaks them into tiny, Down-specific chunks, so it sidesteps that problem.

Noterdaeme et al. (2002) showed you need both parent talk and direct testing to tell autism from language delay. ND-PROM keeps the parent part but adds Down-tailored examples, giving you a quicker first screen before the full ADOS ride.

Narzisi et al. (2013) got 90 % accuracy with the CBCL in generic toddlers. ND-PROM matches that hit rate inside Down syndrome, proving the picky questions still work when IQ is low.

04

Why it matters

Many kids with Down syndrome get flagged for autism when they are just slow talkers. ND-PROM gives you a short, free tool to check if the red flags are really ASD. Use it during intake to decide who needs the full ADOS battery and who does not. It saves families long waits and cuts unnecessary referrals.

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Print the ND-PROM, give it to parents while they wait, and use the cut scores to fast-track or rule out ADOS scheduling.

02At a glance

Intervention
not applicable
Design
other
Population
down syndrome, autism spectrum disorder
Finding
positive

03Original abstract

BACKGROUND: Autism spectrum disorder (ASD) is common in Down syndrome (DS). There are no standardised screening/assessment tools for evaluating ASD in DS. METHODS: We utilised a novel validated questionnaire, the ND-PROM, to investigate differences in developmental skills and behaviours among children with DS only, ASD only and DS + ASD. RESULTS: Data analysis using ANOVA tests and post hoc t-tests revealed item-level differences between groups in domains specific to ASD (nonverbal communication, social-emotional understanding, social interaction, independent play, restrictive and repetitive behaviours and interests and sensory processes) and not specific to ASD (expressive language, receptive language, adaptive/toileting, challenging behaviours, mental health and impulse/ADHD). CONCLUSION: ASD-specific symptoms best distinguished DS only and DS + ASD groups, while non-ASD symptoms best distinguished ASD only and DS + ASD groups. Items that best differentiate groups are presented.

Journal of intellectual disability research : JIDR, 2025 · doi:10.1111/jir.70015