Meningitis impairs memory

Adult survivors of bacterial meningitis are at risk of cognitive impairment. Data from three prospective studies, comparing 155 patients who survived pneumococcal or meningococcal meningitis with 72 matched controls, show impairment in 32% of patients and 6% of controls. Performance was affected across a range of memory tasks and tasks of “attention/executive” function (the speed and fluency of understanding and performing a task such as card sorting) but not tasks involving intelligence or psychomotor function. In general, patients were cognitively slower than controls. The only difference found between causative organisms was a greater risk of memory impairment after pneumococcal disease—these patients tended to be more ill on presentation. No advantage was found in those who had received dexamethasone in the acute stage, and impairment was stable over time.