Attentional dysfunction as a prodrome for Huntington's disease

The onset of choreiform movement disorder is the most widely used indicator for diagnosis of the onset of Huntington's disease. Research in recent years has investigated the possibility that onset of the disease may occur prior to this and is manifest in the form of cognitive impairment, but has been unable to identify the nature of this. Several previous studies have implied that attentional function may be affected. This study employed a more specific and sensitive test battery than had previously been used in this area to investigate the possibility that attentional function was impaired in presymptomatic gene carriers.;Eight carriers and fifteen at-risk non-carriers of the gene were recruited via the genetics services that had tested them for the gene. Two gene carriers were excluded from the analysis since they showed symptoms of movement disorder. These groups were compared in terms of response latency and errors on six sub-functions of attention: alertness, attentional set-shifting, inhibition of unwanted responses, integration of information from different sensory modes, divided attention, and vigilance. The two groups were of widely, differing ages so a covariate analysis taking this into account was performed. Attentional set shifting and the integration of information from different sensory modes were found to be significantly impaired. The two symptomatic participants were compared qualitatively with other participants and appeared to have more impaired performances than either group.;The limitations of the study and its' implications clinically and for future research are discussed. This study offers the possibility that impairments in attention can be detected and that a more specific and sensitive testing procedure can be useful.