Neurocognitive dysfunction in the eosinophilia-myalgia syndrome

The eosinophilia-myalgia syndrome (EMS), a multisystem disorder associated with ingestion of L-tryptophan-containing products, causes sclerodermatous skin changes, cardiopulmonary disease, and a range of peripheral neurologic complications. Many EMS patients also report cognitive difficulty in association with the disease. To determine the frequency of objective neurocognitive impairment in EMS patients with subjective complaints of cognitive difficulty and to assess the relationship of neurocognitive loss with demographic features, degree of peripheral eosinophilia, and psychiatric diagnosis, we compared 24 EMS patients with 32 age- and education-matched healthy controls, using a comprehensive neuropsychological test battery. EMS patients additionally underwent a psychiatric interview and rheumatologic evaluation. Sixty-two percent (15 of 24) of the EMS patients demonstrated neurocognitive deficits. Compared with healthy controls, EMS patients demonstrated significant impairment on tests of verbal memory, visual memory, conceptual reasoning, and motor speed. Cognitively impaired EMS patients did not differ from those without cognitive impairment on demographic markers, degree of peripheral eosinophilia, presence of peripheral neuropathy, or frequency of concurrent psychiatric disorder, including major depression. These data support the hypothesis that EMS is associated with an encephalopathy in addition to its previously recognized peripheral neuropathy and other rheumatologic manifestations.