Classification of vocal tremor using updated consensus‐based tremor classification criteria

Objectives This study characterized the clinical phenotypes of individuals with vocal tremor (VT) using tremor classification criteria published by the International Parkinson and Movement Disorder Society (IPMDS) including laryngeal features from the American Academy of Otolaryngology—Head and Neck Surgery (AAO‐HNS). Methods VT phenotypic descriptors were extracted from participant medical records from 2017 to 2019. Clinical phenotype descriptors included the: (a) chief complaint and discipline for the first appointment, (b) demographics, (c) tremor body distribution, condition, frequency, and progression, (d) exacerbating/alleviating factors, (e) treatment approaches, and (g) neurologic comorbidities. Descriptive statistics were conducted. Results Of 179 meeting inclusion criteria, 2/3 were female; tremor onset affected voice (43%) or extremity (32%) and 2/3 were documented with tremor duration of 3 years or more. Those with primary VT first saw otolaryngology or speech language pathology (59%), whereas those with primary extremity/head tremor first saw neurology (36%). Documentation commonly omitted tremor clinical features such as (a) observed conditions of tremor (64%), (b) laryngeal features (64%), and (c) tremor frequency (92%). Thus, VT classification was based on comorbidity in 49% of patients (ie, essential tremor (48%), dystonia (72%), and Parkinson's disease (100%)) and 32% had inadequate documentation to classify. Conclusion The majority of individuals with VT were unable to be classified based on documented clinical features highlighting the need for consistent multidisciplinary assessment of tremor affecting speech structures. The primary site of tremor determined the first discipline seen. Most commonly classified VT categories included essential tremor (47%), dystonia (28%), Parkinsonism (7%), and isolated VT (19%). Level of Evidence 4. This study characterized electronic medical record documentation of clinical phenotypes of individuals with vocal tremor (VT) using tremor classification criteria published by the International Parkinson and Movement Disorder Society (IPMDS) including laryngeal features from the American Academy of Otolaryngology – Head and Neck Surgery (AAO‐HNS). The majority of individuals with VT were unable to be classified, highlighting the need for consistent multi‐disciplinary assessment and documentation of tremor affecting speech structures. Of 105 individuals able to be classified, 47% were classified as essential