Showing papers by "Eric Siemers published in 2000"

Subtle changes among presymptomatic carriers of the Huntington's disease gene

Abstract: OBJECTIVES To compare the neurological and psychometric characteristics of presymptomatic gene carriers and non-gene carriers who are at risk for developing Huntington9s disease so as to characterise early signs of disease and to identify markers of neurological function that could be used to assess the impact of experimental therapies on the progression of disease, even among those who are clinically presymptomatic. METHODS A sample of people at risk for Huntington9s disease was genotyped and evaluated using subscales of the Wechsler adult intelligence scale–revised (WAIS-R), a quantified neurological rating scale, and computerised physiological measures including speed of movement and reaction time. RESULTS Genotyping and clinical examination determined that 171 participants were presymptomatic gene carriers (PSGCs) and 414 participants were non-gene carriers (NGCs). The PSGCs performed significantly worse when compared with the NGCs on the digit symbol, picture arrangement, and arithmetic subscales of the WAIS-R (p CONCLUSIONS Among Huntington9s disease gene carriers, subtle cognitive and motor deficits precede the onset of sufficient neurological abnormality to warrant a clinical diagnosis of Huntington9s disease.

Confirmation of subtle motor changes among presymptomatic carriers of the Huntington disease gene.

Abstract: Objective To confirm that subtle changes in motor function and reaction time are present in presymptomatic individuals carrying the expanded Huntington disease (HD) allele. Design A case-control, double-blind study comparing presymptomatic HD gene carriers (PSGCs) and nongene carriers (NGCs) at risk for HD. Setting The Department of Medical and Molecular Genetics at a general clinical research center in a midwestern city. Participants Two hundred sixteen individuals at risk for HD who were asymptomatic by self-report and who did not have manifest HD on results of clinical examination, including PSGCs (n = 61) and NGCs (n = 155). Measures Molecular testing was used to determine the number of CAG repeats in the HD gene. A quantified neurologic examination and a battery of physiological measures of central nervous system function measuring speed of movement and reaction time were administered. Results On neurologic examination, the PSGCs exhibited significantly more definite or possible abnormalities than NGCs for overall oculomotor function, saccade velocity, optokinetic nystagmus, chorea of the extremities, and dystonia of the extremities ( P P Conclusions Subtle changes in motor function, speed of movement, and reaction time are present in HD gene carriers who do not exhibit definite choreiform movements and who do not have sufficient signs to make a clinical diagnosis of HD. In addition, a trend toward slower speed of movement and reaction time was observed among this population as their neurologic abnormalities increased.