Cooperative study of hospital frequency and character of transient ischemic attacks. IV. The reliability of diagnosis.

All patients (1,328) suspected of having transient ischemic attacks (TIA) who came to six institutions over a 21-months period were identified. Each case was reviewed by a neurological investigator, and a definite diagnosis of TIA was supported in 39% and ruled out in 30%. The reliability of the neurologist's review diagnosis was assessed by three methods, and close agreement (84% to 93%) was obtained. Factors demonstrated to effect the diagnosis were historical information, neurological training of the examiners, type of symptom complex, presence of carotid artery bruits, and examination during an attack.