Cognitive deficits occur in up to 60 percent of people with MS and affect attention, conceptual reasoning, executive function, visuospatial perception, and recent memory, with relative sparing of language and intellectual function. They have a major impact on all aspects of functioning, particularly employment, and, if severe, may limit the benefits of rehabilitation. Assessment and identification of particular deficits are fundamental to developing strategies to overcome or compensate for them. A cognitive rehabilitation programme in which communication skills training included a combination of cognitive rehabilitation and cognitive-behavioural psychotherapy has been described but not yet evaluated. There is little evidence available on the treatment of specific cognitive deficits. The effects of cognitive training and psychotherapy have been evaluated in a small randomized study of 40 patients, but no clear benefit could be determined apart from an apparent improvement in mood in the treatment arm. A computer-based retraining programme has been reported to have some short-term benefit (9 weeks) in specific attention deficits and related activities of daily living in a study of 22 patients. A recent randomized, double-blind, placebo-controlled trial of computer-aided retraining of memory and attention involving 82 patients did not show benefit. The only medication to be studied in this regard is 4-aminopyridine, but no significant benefit was seen in a small randomized, double-blind, placebo-controlled, cross-over study of 20 patients.

A small exploratory study looked at the potential for the acetyl cholinesterase inhibitor rivastigmine to encourage plasticity in patients with cognitive impairment and suggested that it might help the brain to adapt. Further research is needed to follow this up. Recently another agent, donepezil, has been studied in a single-centre, double-blind, placebo-controlled trial involving 69 patients with MS. Patients received 10 mg donepezil for 24 weeks or placebo and were evaluated across a range of cognitive tests that addressed verbal learning, memory, word fluency, spatial recall, and executive function. Affect and fatigue were also measured. A moderate treatment effect was seen in memory performance but not in any of the other domains. Patients also felt they had improved although there was an element of un-blinding.

In the view of the Committee, these are particularly important symptoms, and it is encouraging to see that they are now recognized as such. More active approaches to management are urgently needed, including larger trials of drug treatments.