Executive dysfunction and cognitive impairment in a large community-based sample with Multiple Sclerosis from New Zealand: a descriptive study.

Multiple Sclerosis (MS) is one of the most common chronic diseases of the central nervous system, and in New Zealand an estimated 4000 people are currently affected. This study was conducted to examine executive functioning, memory and general ability in a community-based sample of 95 participants with MS. The sample included those with relapsing-remitting, secondary progressive, chronic progressive and benign MS with an average duration of illness of 11.8 years. Only 9% of the participants showed no indication of cognitive impairment with most exhibiting mild executive dysfunction across the range of shifting, inhibition, fluency and working memory categories. As this became more widespread, all other measures of cognitive ability and memory also showed evidence of deterioration, but in some, this may have been due to slowed information processing. Overall, there was a high degree of variability in the levels of performance and there was no 'typical' pattern of deficits associated with MS. Thus, a proportion of those living with MS may have to cope with noticeable and unpredictable cognitive decline in addition to their physical disabilities.