HINTS+ to diagnose AICA stroke: systematic review of the diagnostic impact of acute unilateral hearing loss in the acute vestibular syndrome.

Purpose
Head-Impulse, Nystagmus, Test-of-Skew (HINTS) testing is recommended to identify stroke in the acute vestibular syndrome (AVS). Diagnostic accuracy depends on the vascular territory involved, with lower sensitivity for anterior-inferior cerebellar artery (AICA)- than posterior-inferior cerebellar artery (PICA)-territory strokes. Adding new-onset, acute unilateral hearing loss (AUHL) as a fourth central sign has been proposed ("HINTS+") to improve sensitivity for AICA-stroke detection.
Methods
We performed a systematic search (MEDLINE, Embase) to identify studies reporting diagnostic accuracy of bedside examination in AVS patients, including the diagnostic impact of HINTS+. Results were stratified by stroke location.
Results
We identified 4388 citations and included 11 articles (n = 770 patients). Ischemic strokes (n = 319) and acute unilateral vestibulopathy (n = 391) were the most frequent causes. AUHL was most often assessed by finger rub (n = 311), tuning-fork tests (n = 114), or whispered words (n = 169), and was present in 50 patients (central = 29, peripheral = 21). Bedside head-impulse testing was abnormal in 25/29 central cases with AUHL, with 19/25 cases demonstrating an AICA-stroke. Diagnostic accuracy of HINTS (sensitivity = 92.7% [88.7-96.8%]; specificity = 91.1% [86.3-95.8%]) was high. Adding AUHL (HINTS+) increased sensitivity (95.7% [92.7-98.7%]) but decreased specificity (80.7% [70.6-90.7%]), though the latter was largely from bias in patient selection. AUHL had the biggest impact for AICA-territory strokes, increasing sensitivity from 73.3% (59.0-84.0%) to 91.1% (79.3-96.5%).
Conclusions
Testing for AUHL in AVS increased stroke-sensitivity, but this effect was mainly related to AICA-strokes with abnormal head-impulse testing (n = 19/22), where adding AUHL yielded an absolute increase of 17.8% in stroke-sensitivity. In AVS, AUHL should be assessed at the bedside (and ideally confirmed by audiometry).