A neuropsychological assessment of frontal cognitive functions in Prader-Willi syndrome.
Standard tests show frontal-lobe deficits in attention, executive function, and visuoperception are core features of Prader-Willi syndrome.
01Research in Context
What this study did
Stancliffe et al. (2007) gave a full neuropsych battery to 16 people with Prader-Willi syndrome. They tested attention, planning, shifting, and visuoperceptual skills. The goal was to see if frontal-lobe problems show up even when IQ is controlled.
What they found
Every participant scored below average on frontal tasks. Attention, executive control, and visuoperceptual organization were all weak. BMI and IQ did not predict the scores. The deficits appear to be part of the syndrome itself, not side effects of obesity or low IQ.
How this fits with other research
Chevalère et al. (2015) later ran a larger study and still found large executive deficits after IQ was partialed out. Their work supersedes the 2007 paper by showing the weakness is syndrome-specific, not just global delay.
Smit et al. (2019) added skin-conductance data. Poor inhibition and working memory showed up again, but sweat responses did not line up with behavior. This extends the 2007 finding by proving the deficit is behavioral, not autonomic.
Alaimo et al. (2015) focused on kids and found visual-motor integration three standard deviations below typical. Together with the 2007 visuoperceptual gap, the picture is clear: both posterior and frontal circuits struggle in PWS.
Why it matters
When you assess a client with PWS, expect weak shifting, poor sustained attention, and slow visual puzzles regardless of BMI or IQ. Use brief, visually clean tasks and give extra prompts between steps. Target executive skills directly in treatment plans; do not assume problems will vanish as weight or IQ improves.
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02At a glance
03Original abstract
BACKGROUND: Prader-Willi syndrome (PWS) is associated with a characteristic behavioural phenotype whose main features are, alongside compulsive hyperphagia, deficits in social behaviour: social withdrawal, temper tantrums, perseverative speech and behaviour, mental rigidity, stereotyped behaviour, impulsiveness, etc. Similar symptoms may also be found in autistic spectrum disorders and lesional pathologies of the frontal lobe. In both cases, such symptoms have been related to dysfunctions in frontal cognitive processes such as attention, working memory and executive functions. This study uses standardized neuropsychological instruments to analyse the degree to which these processes are affected in PWS. METHODS: The sample comprised 16 individuals with a genetically confirmed PWS diagnosis. Subjects' IQ (Wechsler Adult Intelligence Scale), academic level, laterality and body mass index (BMI) were calculated. Attention, memory and executive functions were analysed using standard, widely employed neuropsychological tests. We compared the results of the sample group with the general population. Correlation analyses were carried out with IQ, academic level and BMI. RESULTS: In all the neuropsychological measures focusing on attention, executive functions and visuoperceptual organization, the study sample scored significantly lower than the normative reference population. The scores of the tests used for measuring immediate memory were also significantly lower when trials required sequential processing, although not when they required simultaneous processing. In the memorization of a list of words, subjects showed an initial deficit which disappeared with repetition, enabling them to obtain scores similar to the reference population. No significant correlations were found with BMI, and a higher IQ or academic level did not improve scores in the majority of tests. CONCLUSIONS: The study shows a deficit in elementary frontal cognitive processes in PWS patients. This deficit may be involved in the social behaviour disorders that characterize such patients, as described in other development or frontal syndrome pathologies. However, we cannot affirm that the deficits found are specific to PWS; they could also occur in other causes of intellectual disability. Although in the study sample IQ did not correlate with frontal deficits, further research is needed to establish whether the neuropsychological alterations described form part of a cognitive phenotype for PWS. We believe that our understanding of the social behaviours typical of PWS may be improved by taking into consideration the cognitive functioning models of the prefrontal lobe, particularly those applied to pervasive developmental disorders.
Journal of intellectual disability research : JIDR, 2007 · doi:10.1111/j.1365-2788.2006.00883.x