ABSTRACT
BACKGROUND/AIMS: The main purpose of the study was to determine whether the predicted age of onset of Huntington's disease (HD) affects cognitive function as measured by the Wechsler Adult Intelligence Scale-Revised (WAIS-R). The subscales and subtests, and their potential selectivity were examined in preclinical HD (30 mutation carriers and 34 noncarriers) with no motor or neuropsychiatric signs of HD. METHODS: The predicted age of onset in mutation carriers was calculated by a regression equation allowing this group to be divided according to whether onset was predicted as within 12 years (HD+CLOSE) or longer than this (HD+DISTANT). RESULTS: The HD+CLOSE group scored significantly lower on Verbal, Performance, and Full Scale IQ compared to noncarriers and performed significantly lower on 7 of the 11 WAIS-R subtests, with low average scores in language abilities, attention, abstract thinking, problem solving, visuospatial ability, and psychomotor speed. CONCLUSION: These low average scores affect general intelligence and functioning of HD+CLOSE carriers and are likely to reflect dysfunction of frontal cortex and frontostriatal circuits more than a decade before manifest symptoms. Our findings support a continuous linear model of slow cognitive decline in HD.
Subject(s)
Huntington Disease/diagnosis , Huntington Disease/psychology , Intelligence , Wechsler Scales , Adult , Attention , Cognition Disorders/etiology , Early Diagnosis , Female , Humans , Language , Linear Models , Male , Middle Aged , Problem Solving , Psychomotor Performance , Space Perception , Thinking , Time Factors , Visual PerceptionABSTRACT
The aim of the present study was to investigate verbal fluency in preclinical Huntington's disease (HD). Phonemic and semantic fluency and the rate of word production over time were assessed for 29 asymptomatic gene carriers and 34 noncarriers of HD. The relationship between fluency tasks and other cognitive domains was investigated. Compared to noncarriers, carriers produced fewer words and produced them more slowly in the phonemic fluency task but not in the semantic fluency task. When the carrier group was divided on the basis of Predicted-Years-To-Onset (PYTO), only carriers with <12 PYTO performed worse than noncarriers on both fluency tasks. Correlational analyses revealed that phonemic fluency was associated with cognitive speed and working memory, while semantic fluency was linked with crystallized abilities. The difference between carriers and noncarriers in phonemic fluency and a difference between the two carrier groups (<12 PYTO and >or=12 PYTO) in semantic fluency, but not in phonemic fluency, suggest that frontostriatal deficits may precede temporal involvement in preclinical HD.
Subject(s)
Heterozygote , Huntington Disease/physiopathology , Phonetics , Semantics , Verbal Behavior/physiology , Adult , Cognition/physiology , Female , Humans , Huntington Disease/complications , Huntington Disease/genetics , Male , Middle Aged , Neuropsychological Tests , Reaction Time/physiology , Speech Disorders/etiology , Speech Disorders/psychologyABSTRACT
The present study reports a two-year follow-up of psychological effects of predictive testing for Huntington's disease. Questionnaires assessing depression, general health, well-being, self injurious behavior, life satisfaction, and lifestyle were completed by 35 carriers and 58 non-carriers before the predictive test, and 2, 6, 12, and 24 months afterwards. Both carriers and non-carriers showed high suicidal ideation before the predictive testing. Depression scores and frequency of suicidal thoughts increased for carriers, compared to non-carriers, over time. There were no differences regarding life satisfaction or life style between carriers and non-carriers. Predictive testing was beneficial in reducing overall ill-health symptoms and increasing well-being for those initially expressing concern about Huntington's disease. The importance of assessing suicidal ideation and of continuing to provide adequate support is emphasized.
