Cognitive Decline as Early Manifestation of Multiple Sclerosis: A Case Series

Case 1: Female, 58 years old, complained of executive dysfunction, apathy, psychomotor agitation, inattention, inability to complete tasks, gait disorder and imbalance that progressed in about 6 months. Brain and spinal cord MRI showed demyelinating lesions typical of Multiple Sclerosis (MS) and exclusive oligoclonal bands (OCB) in the CSF. Case 2: Female, 41 years, reports a 2-month history of progressive behavioral alteration, childish manners, associated to dysfunction in semantic episodic memory, prospective memory, arithmetic skills, language (oral and written) and executive functions, besides weakness in the left lower limb, optic neuritis in the left eye, sphincter and cerebellar dysfunction. MRI showed typical MS lesions with predominance in infratentorial and medullary regions, still waiting OCB search result in CSF and serum. Case 3: Female, 34 years, about 8 months, presented progressive cognitive dysfunction (forgetting people names and places, difficulty evoking words), and executive disfunction which led to job relocation due to loss of functionality. MRI showed typical MS lesions and CSF demonstrated exclusive OCB. Discussion: Cognitive decline in MS can occur in early stages, even in the absence of other neurological deficits. Usually, processing speed information, learning, visual and verbal memory are the most frequently affected domains¹. In the case 1, a concomitant diagnosis of frontotemporal dementia was made in the follow-up, while in case 2 and 3, the cognitive decline was exclusively related to MS. Comprehensive neuropsychological testing were crucial to refine bedside suspicion of cognitive impairment due solely to MS. Final Comments: The diagnostic dilemma in differentiating cognitive impairment due to MS from coexistent neurodegenerative disorders will likely become more common due to aging population and increasing MS diagnosis. It is important to keep a broad differential diagnosis in patients who present uncommon clinical features as first disease presentation or early in the disease course.