Late-onset multiple sclerosis

OBJECTIVE: The onset of multiple sclerosis (MS) after age 50 is infrequent and presents a diagnostic challenge. The purpose of the present study was t o review the prevalence, presentation, and clinical characteristics of late -onset MS. DESIGN: A retrospective chart review. SETTING: The Multiple Sclerosis Center at Sheba Medical Center, Israel. PARTICIPANTS: 640 patients with a definite diagnosis of MS. MEASUREMENTS: Diagnosis of MS was established according to Poser criteria a nd confirmed by brain magnetic resonance imaging (MRI) using our unit's com puterized database. Late-onset MS was defined as the first presentation of clinical symptoms after the age of 50 years. For each patient, age, gender, clinical presentation, disease course, neurological involvement, disease d uration, neurological disability assessed, and Progression Index (PI) were analyzed. All patients were interviewed using the structured clinical inter view for DSM-IV, SCID-lifetime Hebrew version. RESULTS: Of 640 MS patients, 30 (4.6%) were diagnosed as suffering from lat e-onset MS. Mean age at onset was 53.5 +/- 3.1, range 50 to 62 years. Femal e to male ratio was 1.73:1. Mean disease duration was 7.6 years, range 2 to 11 years. In 50% of patients the disease course was relapsing-remitting. M otor symptoms were the most common neurological presentation at onset (63.3 %). Major depressive episode was diagnosed in 6 out of 30 patients (20%) in the two years prior to the diagnosis of MS. After a mean disease duration of 7.6 years there was a marked increase in sphincteric and cerebellar invo lvement. In addition 7 out of 30 patients had suffered a major depressive e pisode within 4 years of diagnosis. Mean PI was 0.81, suggesting rapid neur ological deterioration. CONCLUSIONS: Late-onset MS is not rare and may present as major depression and, although neurological presentation at onset is similar to that of youn g adults, progression to disability is more rapid and a primary progressive course is more prevalent.