Background and Aim Pulsatile Tinnitus (PT) is a type of tinnitus which can be produced by underlying vascular pathologies of arterial or venous origins. PT can sometimes be heard through bare-listening or auscultation, however, sensitivity is poor. Many research groups, including ours, have begun implementing in-clinic transcanal recordings to better understand the categorization of the sounds perceived. Patients with PT caused by an arterial source, such as a fistula, often describe their tinnitus as high pitched, whereas PT caused by a venous source is often described as a whooshing, humming, or buzzing sound. Transcanal recordings offer a promising approach to objectively assess PT sounds and correlate them with underlying anatomical anomalies. Our study investigated the utility of transcanal recordings and corresponding spectrograms to objectively classify PT sounds and correlate them with underlying venous anatomical anomalies.

Methods A cohort study was conducted involving 89 patients with PT. Transcanal recordings were performed during patient clinic visits using a microphone placed within the ear canal, capturing sound pressure waves generated by PT. Spectrograms obtained from these recordings were analyzed to classify PT sounds and were correlated with venous anatomical features identified from contrast enhanced, venous phase diagnostic imaging, such as magnetic resonance venography (MRV), computed tomography venography (CTV), and digitally subtracted angiography (DSA).

Results Four distinct patterns of PT sounds were identified based on spectrogram appearance of transcanal recordings: broadband, narrowband, heartbeat, and negative. Broadband sounds were found to be associated with venous anomalies such as transverse sinus stenosis and mastoid bone dehiscence/diverticulum. Narrowband sounds were predominantly identified for patients with a dural arteriovenous fistula (dAVF).

Conclusion These findings suggest that transcanal recordings can be a valuable diagnostic tool for PT objectification and characterization the structural causes and hemodynamic mechanisms underlying PT. Broadband sounds may be indicative of venous anomalies, while narrowband sounds could signal a dAVF. Transcanal recordings offer a promising adjunctive tool for objectively assessing PT sounds from their spectral characteristics and correlating these with underlying anatomical anomalies. This approach holds potential for improving diagnostic accuracy and guiding personalized treatment strategies for patients with PT.

Disclosures N. Cancelliere: None. G. Sidora: None. Z. Hussain: None. D. Steinman: None. V. Mendes Pereira: None.