Assessment & Research

Assessment of cognitive decline associated with aging: a comparison of individuals with Down syndrome and other etiologies.

Das et al. (1995) · Research in developmental disabilities 1995
★ The Verdict

Use three five-minute tasks to spot early dementia in adults with Down syndrome starting at 40.

✓ Read this if BCBAs serving adults with Down syndrome in day programs or group homes.
✗ Skip if Clinicians working only with children or adults under 40.

01Research in Context

01

What this study did

Researchers tested the adults with Down syndrome and the adults with other intellectual disabilities.

All were between 40 and 65 years old.

They used three quick paper tasks: Number Finding, Expressive Attention, and Speech Rate.

Each task took under five minutes.

The goal was to see who showed early signs of dementia.

02

What they found

After age 40, adults with Down syndrome scored much lower on all three tasks.

The drop was sharper than in adults with other disabilities.

Number Finding showed the biggest gap.

This suggests dementia starts earlier in Down syndrome.

03

How this fits with other research

Micai et al. (2021) adds that inhibition problems last a lifetime.

Their meta-analysis shows even young people with Down syndrome struggle with self-control.

Witecy et al. (2017) found language skills stop growing after the teen years.

This lines up with our study—once language plateaus, cognitive decline can begin.

Eussen et al. (2016) seems to disagree.

They found preschoolers with Down syndrome already show weaker delay skills than kids with other ID.

But the gap is about timing, not contradiction.

Early delays in childhood grow into sharper adult decline.

04

Why it matters

Start yearly dementia screens at age 40 for clients with Down syndrome.

Use the three quick tasks: Number Finding, Expressive Attention, and Speech Rate.

Early detection lets you adjust goals and train caregivers sooner.

Free CEUs

Want CEUs on This Topic?

The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.

Join Free →
→ Action — try this Monday

Add the Number Finding task to your next session with any Down syndrome client over 40.

02At a glance

Intervention
not applicable
Design
quasi experimental
Sample size
72
Population
down syndrome, intellectual disability
Finding
positive

03Original abstract

Cognitive processes and their decline with aging were studied in individuals with Down Syndrome (DS) and individuals of comparable mental handicap without Down Syndrome (NonDS). The cognitive processes were measured by tests of Planning, Attention, Simultaneous, and Successive processing. The DS and NonDS samples were divided into age groups of 26-40 years (DS = 23, NonDS = 23) and 41-60 years (DS = 8, NonDS = 18). Analyses of variance using factor scores demonstrated articulation to be significantly poorer in the DS sample at and above 40 years. Specifically, the tests that showed the interaction effects between DS/NonDS and the two age groups were Number Finding, Expressive Attention, and Speech Rate. When the cutoff age was raised to 50 years, an additional Attention and Planning task (Receptive Attention and Matching Numbers) also showed the interaction effect. These tests hold the promise for diagnosing early signs of dementia of Alzheimer type. Implications for rehabilitation are described.

Research in developmental disabilities, 1995 · doi:10.1016/0891-4222(94)00032-5