Personality and behavioural changes do not precede memory problems as possible signs of dementia in ageing people with Down syndrome.

OBJECTIVE: The objective was to find out whether changes in personality and adaptive functioning or memory processes decline first in ageing people with Down syndrome. METHODS: We measured these variables cross-sectionally in a Dutch sample (22 to 62 years of age) of 68 institutionalised people with Down syndrome. RESULTS: The scores on all the variables except one of the temperament scales were found to decline gradually with increasing age, but deterioration of episodic memory started earlier. CONCLUSIONS: We argued that a subset of our sample suffered from dementia. Furthermore, the data suggested that immediate memory impairment is one of the earliest signs of the disease in people with Down syndrome, just as it is in the general population. Copyright © 2016 John Wiley & Sons, Ltd.

Exploring the Flynn effect in mentally retarded adults by using a nonverbal intelligence test for children.

Increases in the scores on IQ tests across generations have been called the Flynn effect (FE). One of the unresolved questions is whether the FE affects all subsamples of the intellectual ability distribution equally. The present study was aimed at determining the size of the FE in moderately mentally retarded individuals. A nonverbal intelligence test developed for children, the Snijders-Oomen Nonverbal Intelligence Test (SON), was administered to 32 retarded adults with a mental age of 3-6 years. Sixty-nine children with a biological age in the same range and with normal intelligence served as a comparison group. Both an older and a more recent version of the SON were presented to all participants in a counterbalanced order. The proportion of items answered correctly was taken as a measure of the dependent variable. It was found that a FE existed in both the group of children and in the group of retarded adults, but that the FE was largest in the latter group. The importance of not using obsolete test norms when diagnosing mental retardation was stressed, and possible causes of the Flynn effect were discussed.

Psychological and speech studies in Rubinstein-Taybi syndrome.

Forty individuals with Rubinstein-Taybi syndrome were tested using an extensive test battery to obtain more insight about their intelligence level, social competency, temperament, and behavior as well as articulation and receptive and expressive language level. Examination of individuals in the Netherlands who have this rare syndrome has been extensive, allowing some generalizations to be made. The intelligence level of affected individuals is usually low, although some persons have much higher scores than do others. The tested individuals were remarkably consistent in their social competency, temperament, and behavior. They were able to make good use of their limited verbal abilities. Comparable studies of other groups of persons with a specific syndrome are needed to determine whether the present findings are specific for Rubinstein-Taybi syndrome or may be found among persons with other syndromes.