Voice tremor: what we know and what we do not knowGillivan-Murphy, Patriciaa; Miller, NickbCurrent Opinion in Otolaryngology & Head & Neck Surgery: June 2011 - Volume 19 - Issue 3 - p 155–159 doi: 10.1097/MOO.0b013e328345970c Speech therapy and rehabilitation: Edited by Paul Carding Abstract Author Information Purpose of review: Voice tremor is a feature of many neurological conditions. Historically, clinical evaluation of voice tremor has relied on auditory–perceptual evaluation. We review developments in understanding of voice tremor that advocate additional approaches (acoustic, fibreoptic nasolaryngoscopic examination) to evaluation and stress the contribution from multiple sites in the speech mechanism to perceived tremor. Recent findings: An isolated focus on the speech signal does not identify the source/s of tremor. Structures in the pharynx and larynx can be important sources of perceived voice tremor. In addition to a sustained vowel phonatory task for evaluation, fibreoptic nasolaryngoscopic examination is recommended to observe tremor behaviour in different anatomic sites using different speech tasks; acoustic analysis is recommended to quantify tremor and enhance understanding of underlying mechanisms. Tremor measures (rate, periodicity, magnitude of frequency and amplitude tremor) have proved useful in differentiating speakers with tremor from normal speakers. Differentiating between tremor aetiologies is proving more challenging. The investigation of a conceptual model of voice tremor to understand the effect that oscillations in different parts of the speech mechanism have on the speech signal is an important development in the field. Summary: A sustained phonatory vowel task with fibreoptic nasolaryngoscopic examination of pharyngeal and laryngeal musculature, supplemented by acoustic measures, is currently recommended for clinical identification, quantification and characterization of voice tremor. aMater Misericordiae University Hospital, Dublin, Ireland bInstitute of Health and Society, Newcastle University, Newcastle, UK Correspondence to Patricia Gillivan-Murphy, MSc, Clinical Specialist, Speech & Language Therapist, Mater Misericordiae University Hospital, Eccles Street, Dublin 7, Ireland Tel: +353 18034105; e-mail: firstname.lastname@example.org © 2011 Lippincott Williams & Wilkins, Inc.