TRANSIENT NEUROLOGICAL ATTACKS IN THE GENERAL-POPULATION - PREVALENCE, RISK-FACTORS, AND CLINICAL RELEVANCE

Background and Purpose Patients with typical transient ischemic attack s (TIAs) have a higher risk of stroke but a lower risk of cardiac even ts than patients with nonspecific transient neurological symptoms. We assessed the prevalences of typical TIAs and nonspecific transient neu rological attacks (TNAs) and their determinants in the general populat ion because such data are virtually absent. Methods The Rotterdam Stud y is a population-based cohort study of 7983 subjects, aged 55 years a nd over, conducted in a district of Rotterdam. the Netherlands. At bas eline examination, a history of episodes of disturbances in sensibilit y, strength, speech, and vision that lasted less than 24 hours and occ urred within the preceding 3 years was determined by a trained physici an. When such a history was present, information on lime of onset, dur ation, and disappearance of symptoms and a detailed description of the symptoms (in ordinary language) were obtained. Subjects were classifi ed by a neurologist as typical TIA or nonspecific TNA. Results Prevale nce of TNAs was 1.9% in subjects aged 55 to 64 years, 3.5% in subjects aged 65 to 74 years, 4.3% in subjects aged 75 to 84 years, and 5.1% i n subjects aged 85 years or over, Prevalence figures for typical TIA w ere 0.9%, 1.7%, 2.3%, and 2.2% and for nonspecific TNA 1.0%, 1.8%, 2.0 %, and 2.9%, respectively. Clinical parameters such as number of attac ks, onset, duration, and disappearance of symptoms were similar for ty pical TIA and nonspecific TNA. Increased age, male sex, diabetes melli tus, low HDL cholesterol, Q-wave myocardial infarction on electrocardi ogram, and carotid atherosclerosis were related to typical TIA, wherea s increased age, hypertension, low HDL cholesterol, smoking; and angin a pectoris were associated with nonspecific TNA, Conclusions About hal f of the subjects with a TNA had symptoms that were not entirely typic al for a TIA. Differences in associations with risk factors between ty pical TIA and nonspecific TNA point toward different underlying mechan isms of symptoms and may lead to different ancillary investigations an d possibly treatment.