Cognitive Decline Tracked in Multiple Sclerosis in Longitudinal Study

Cognitive abilities declined during a longitudinal study of multiple sclerosis (MS) patients, according to research published by the Kessler Foundation and the Cleveland Clinic. The study is one of the longest longitudinal studies of cognition in MS.

The researchers wanted to explore and track the cognitive impairment among 22 patients enrolled an ongoing phase 3 trial of intramuscular interferon beta-1a. The participants underwent a longitudinal investigation which compared neuropsychological test performances at baseline and at the 18-year follow up. The patients were enrolled in the original Avonex study conducted in the early 1990s.

“While cognitive impairment is known to affect 40 to 65% of individuals with MS, few studies have followed the pattern of cognitive decline over time, which is important for understanding long-term care and outcomes associated with MS,” author Lauren B Strober, PhD senior research scientist at Kessler Foundation, said in a press release. “Our study was based on a unique sample of 22 patients who underwent neuropsychological testing at entry into the original phase 3 clinical trial of intramuscular interferon beta-1a, and again at 18-year follow up.”

Declines were observed in the MS patients in areas such as information processing speed, simple and complex auditory attention, episodic learning and memory, and visual constructions. Nearly half of the patients (41 percent) were found to be cognitively impaired at baseline. At the 18-year mark, 13 patients (59 percent) were found to be cognitively compared, when evaluated by the researchers. Both the unimpaired and impaired groups of patients appeared to experience cognitive decline using these measures. One measurement scale, the Symbol Digit Modalities Test showed a group × time interaction. The researchers determined this scale displayed a steeper decline in the unimpaired than the impaired group compared to baseline measurements.

“These longitudinal data contribute substantially to our knowledge of the course of cognitive decline in MS,” John DeLuca, PhD, VP of Research & Training at Kessler Foundation, continued in the statement. “In light of the young age at diagnosis, this perspective is fundamental to the development of rehabilitation strategies that meet the needs of people dealing with the cognitive effects of MS.”

Cognitive impairment is observed in approximately 40-65 percent of MS patients. The researchers set to explore this unknown territory because so little is known about the rate and patterns of cognitive decline over the course of the illness.