Cognitive impairment in secondary progressive multiple sclerosis (SPMS) is linked to significantly worse white matter integrity in areas important to cognitive function, according to Dr. Kim A. Meijer and associates.
Compared with a control group of 32 healthy people, the 12 cognitively impaired and 18 cognitively preserved SPMS patients had significant loss of white matter integrity across the white matter skeleton. SPMS patients with cognitive impairment had more severe and extensive damage in several places, including the fornix, superior longitudinal fasciculus, and forceps major.
Poor cognitive function in SPMS patients was associated with lower premorbid IQ, female sex, and higher age. Combined with white matter integrity, these factors accounted for 48% of the difference in cognition between cognitively impaired and cognitively preserved SPMS patients.
“As with [relapsing remitting multiple sclerosis], damage to WM [white matter] tracts also appears to be a potential mechanism for cognitive impairment in SPMS patients. This study shows that the loss of WM integrity assessed using [tract-based spatial statistics] helps to explain cognitive decline and emphasizes the relevance of studying patterns of WM disruption throughout the brain in relation to cognitive deficits,” the investigators concluded.
Find the full study in the Multiple Sclerosis Journal (doi: 10.1177/1352458515622694).