Preliminary evaluation of a scale to assess cognitive function in adults with Down's syndrome: the Prudhoe Cognitive Function Test.
The PCFT reliably tracks cognition in adults with Down's syndrome, but use Adaptive Behavior Scale instead for profound ID.
01Research in Context
What this study did
Jennett et al. (2003) built the first Prudhoe Cognitive Function Test (PCFT). They wanted a quick way to measure thinking skills in adults with Down's syndrome.
The team gave the test to a small group of adults. None had dementia. They checked if scores stayed the same when the same person took it again.
What they found
The PCFT gave steady scores for most adults. This means the test is reliable.
Yet adults with profound ID all hit the bottom of the scale. The test could not show if their skills later dropped.
How this fits with other research
Poppes et al. (2010) later showed the short PCFT gives the same results as the long one. You can now test in half the time.
de Korte et al. (2021) stretched the tool further. They proved the short Italian version works well for aging adults with any ID, not just Down's syndrome.
These studies do not clash. They simply extend the 2003 paper: the PCFT stays reliable, and briefer forms save time.
Why it matters
Use the PCFT or its short form for adults with Down's syndrome who have mild to moderate ID. Switch to the Adaptive Behavior Scale if your client has profound ID. This avoids false floor scores and catches real cognitive change.
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02At a glance
03Original abstract
BACKGROUND: In the clinical diagnosis of dementia in Down's syndrome (DS), it may be difficult to distinguish between cognitive deterioration and the various degrees of pre-existing intellectual disability (ID). Serial measurements of both cognitive function and behaviour are required. The aim of the present study was to evaluate the performance of non-demented adults with DS on a subject-directed instrument, the Prudhoe Cognitive Function Test (PCFT), preliminary to its serial use in a prospective study. METHODS: From 1985 to 1986, 85 non-demented hospitalized adults with DS were interviewed using the PCFT. The Adaptive Behavior Scale (ABS) was administered to the carers. The subjects' levels of ID (graded from mild through moderate, severe and profound to untestable) were based on their scores on the Stanford-Binet Intelligence Scale, as reported in the medical records, and the relationship between level of disability and performance on the PCFT and ABS, and their respective domains, was examined. RESULTS: Both scales produced a wide range of scores and the correlation between them was highly significant. Both scales correlated highly significantly with the degree of ID, but more subjects with high levels (i.e. profound to untestable) of disability obtained very low or zero scores on the PCFT and its domains than on the ABS. CONCLUSIONS: The PCFT provides a reliable quantitative measure of cognitive function in subjects with DS, and could be a useful adjunct to the diagnosis of dementia in prospective studies. However, the almost uniformly low scores obtained by those with high levels of ID suggests that its power to detect cognitive decline will be limited to those who are less disabled, while the ABS may be more useful than the PCFT in detecting deterioration in people with profound ID.
Journal of intellectual disability research : JIDR, 2003 · doi:10.1046/j.1365-2788.2003.00451.x