Cognitive changes related to multiple sclerosis (MS) were first mentioned by Jean-Martin Charcot in 1877; however, it is only within the past 25-30 years that cognitive impairment in MS has received significant clinical study. Despite a growing body of research, though, formal screening of cognitive function is not always part of routine MS clinical care.
Q)How common are cognitive symptoms in MS?
Cognitive changes affect up to 65% of patients in MS clinic samples and about one-third of pediatric MS patients.1 Cognitive deficits occur in all the MS disease courses, including clinically isolated syndrome, although they are most prevalent in secondary progressive and primary progressive disease.1 Cognitive changes have even been observed in radiographically isolated syndrome, in which MRI changes consistent with MS are observed without any neurologic symptoms or signs.2
Q)What cognitive domains are affected in MS?
Strong correlations have been demonstrated between cognitive impairment and MRI findings, including whole brain atrophy and, to some degree, overall white matter lesion burden. Cognitive changes also result from damage in specific areas, including deep gray matter and the corpus callosum, cerebral cortex, and mesial temporal lobe.3-5
The type and severity of cognitive deficits vary widely among people with MS. However, difficulties with information processing speed and short-term memory are the symptoms most commonly seen in this population. Processing speed problems affect new learning and impact memory and executive function. Other domains that can be affected are complex attention, verbal fluency, and visuospatial perception.1
Q)Are cognitive symptoms in MS progressive?
Not everyone with cognitive symptoms related to MS will show progressive changes. However, in a longitudinal study, increasing age and degree of physical disability were predictive of worsening cognitive symptoms. Also, people who demonstrate early cognitive symptoms may experience greater worsening.6
Q)What impact do cognitive symptoms have?
Changes in cognition are a common reason for someone to experience performance issues in the workplace and as such significantly affect a person’s ability to maintain employment. Impaired cognition is a primary cause of early departure from the workforceand has significant implications for self-image and self-esteem.7
Furthermore, cognitive symptoms can impact adherence to medications. They also can negatively affect daily life, through increased risk for motor vehicle accidents, difficulties with routine household tasks, and significant challenges to relationships (particularly but not exclusively those with caregivers).
Continue to: How are cognitive symptoms assessed?