Background and purpose
The clinical diagnosis of a transient ischemic attack (TIA) can be difficult. Evidence based criteria hardly exist. We evaluated if the recently proposed ‘Explicit Diagnostic Criteria for TIA’ (EDCT), an easy to perform clinical tool focusing on type, duration and mode of onset of clinical features, would facilitate the clinical diagnosis of TIA.
Methods
We used data from patients suspected of a TIA by a general practitioner (GP) and referred to a TIA service in the region of Utrecht, The Netherlands, who participated in the ‘Markers in the Diagnosis of TIA’ (MIND-TIA) study. Information about the clinical features was collected with a standardized questionnaire within 72 hours after onset. A panel of three experienced neurologists ultimately determined the definite diagnosis based on all available diagnostic information including a six month follow-up period. Two researchers scored the EDCT. Sensitivity, specificity, and predictive values of the EDCT were assessed using the panel diagnosis as reference. A secondary analysis was performed with modified sub-criteria of the EDCT. 
Results
Of the 206 patients, 126 (61%) had a TIA (n=104) or minor stroke (n=22), and 80 (39%) an alternative diagnosis. Most common alternative diagnoses were migraine with aura (n=24, 30.0%), stress related or somatoform symptoms (n=16, 20.0%), and syncope (n=9, 11.3%). The original EDCT had a sensitivity of 98.4% (95%CI: 94.4 – 99.8), and a specificity of 61.3% (49.7 – 71.9). Negative and positive predictive values were 96.1% (86.0 – 99.0) and 80.0% (75.2 – 84.1) respectively. The modified EDCT showed a higher specificity of 73.8% (62.7 – 83.0) with the same sensitivity, and a similar negative predictive value of 96.7%, but a higher positive predictive value of 85.5% (80.3 – 89.5). 
Conclusions
The EDCT has excellent sensitivity and negative predictive value, and could be a valuable diagnostic tool for the diagnosis of TIA.

2 - DIAGNOSTIC ACCURACY OF EXPLICIT DIAGNOSTIC CRITERIA FOR TIA: A VALIDATION STUDY