The common belief that primary dystonia is a purely motor disorder has recently been challenged. We examined separately the cognitive profiles of symptomatic (SYM) and nonsymptomatic (N-SYM) groups of carriers of DYT1 mutation using a comprehensive neuropsychological test battery. Self-report inventories of anxiety, depression, and pain levels were also administered, as well as manual motor dexterity assessment. Each group was matched with healthy controls by age, sex, mother tongue, and education. No significant differences between the SYM group to its control group were found on cognitive tests evaluating verbal and nonverbal abstract abilities, attention, information processing speed, and spatial organization. However, the SYM group showed increased verbal memory retroactive interference. Interestingly, the patients also showed higher semantic fluency performance. No significant differences between the N-SYM group to controls were found. It was concluded that symptomatic DYT1 mutation carriers do not suffer the distinctive cognitive decline that is seen in other primary degenerative extrapyramidal disorders.
Copyright 2006 Movement Disorder Society.