BRIEF COMMUNICATION Facial tremors in patients with and without parkinsonism Malco Rossi 1 • Miguel Wilken 1 • Pierre Morisset 1 • Sofia Farin ˜a 1 • Daniel Cerquetti 1 • Marcelo Merello 1,2 Received: 28 April 2016 / Accepted: 20 July 2016 Ó Springer-Verlag Italia 2016 Abstract Facial (lip and jaw) tremors can be an early sign of Parkinson’s disease (PD), essential tremor and other parkinsonisms. Its response to acute dopaminergic therapy and further predictive clinical diagnosis has not been pre- viously addressed. The aim of this study was to evaluate facial tremors response to acute dopaminergic therapy and further predictive value for clinical diagnosis. A retro- spective review of medical records from patients with recent onset of facial tremor, with or without parkinsonism, submitted to acute levodopa challenge for clinical predic- tion of sustained long-term dopaminergic response was conducted. Twenty-eight out of 559 patients (5 %) had facial tremors, which responded to levodopa in 46 % of patients. Facial tremors response to acute levodopa chal- lenge showed 92 % sensitivity and 93 % specificity to predict a final PD diagnosis. In PD patients, facial tremor magnitude of response to levodopa was not different from that of hand rest tremor (p = 0.8). Facial tremors, although infrequent, can be an early sign of PD. Positive response to acute levodopa challenge predicts long-term PD diagnosis. Keywords Tremor Á Levodopa Á Parkinson’s disease Á Chin Á Facial Á Jaw Introduction Diagnosis and treatment of patients with tremor can be a challenge in clinical practice, as there exists an overlap among different neurodegenerative disorders that may show tremor as an initial clinical feature. Clinical pre- sentation of tremor in Parkinson’s disease (PD) patients varies; some patients will present action or postural tremors instead of the classical resting tremor. This led to expansion of PD tremor definition under UK Parkinson’s Disease Society Brain Bank criteria (UKPDSBB) to include any form of pathological tremor [1]. Facial (mainly lip and jaw or chin) tremors can be present in common neurodegenerative disease and in unusual tremor syndromes [2, 3]. Facial tremors as initial manifestations of PD are uncommon [4]. It raises suspi- cion for diagnosis of other prevalent diseases, such as essential tremor (prevalence 415:100,000) [5], multiple system atrophy (prevalence 4.4:100,000) [4], drug-in- duced tremor or parkinsonism, or hereditary geniospasm, rather than PD. As several differential diagnoses are possible in patients with facial tremors as initial mani- festations of their parkinsonism, treatment can be chal- lenging. Acute levodopa challenges are useful to predict sustained response to levodopa and favor possible PD diagnosis. Postural, intentional and rest tremor response to dopaminergic therapy varies considerably among PD patients. Facial tremors response to dopaminergic therapy and its use for predictive clinical PD diagnosis has not been described. Therefore, the aim of this study was to evaluate facial tremors response to acute dopaminergic challenge. & Marcelo Merello mmerello@fleni.org.ar 1 Movement Disorders Section, Neuroscience Department, Raul Carrea Institute for Neurological Research (FLENI), Montan ˜eses 2325, 1428 Ciudad Auto ´noma de Buenos Aires, Argentina 2 Argentine National Scientific and Technological Research Council (CONICET), Buenos Aires, Argentina 123 Neurol Sci DOI 10.1007/s10072-016-2683-x