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Patient A is a 69-year-old man with a 5-year history of progressive right hand then leg tremor, stiffness and slowness with recent diagnosis of Parkinson’s disease (PD) 3 months prior to this encounter. Examination demonstrated unilateral right-sided facial droop at rest largely sparing the upper face and with accompanying decreased right lower facial muscle activation. Unified Parkinson’s Disease Rating Scale motor examination score (UPDRS-III) was 26. UPDRS-III facial expression subscore had decreased from 2 to 1 since starting carbidopa/levodopa 50–200 three times daily 3 months prior.
Similarly, patient B is a 77-year-old woman with a 3-year history of tremor starting in her left hand and a diagnosis of PD since 2017. Examination demonstrated resting unilateral left-sided facial droop involving both the upper and lower face with associated upper-worse-than-lower facial asymmetry. UPDRS-III score was 24 including a UPDRS facial expression score of 1. She has been treated with ropinirole since 2018 and was increased from 1.5 mg per day to 3 mg per day 6 months prior to this encounter.
Both patients had facial muscle activation on the affected side that was reduced and slowed without synkinesis. Neither had a history of Bell’s palsy. Both patients’ MRI brain without contrast were unrevealing. In both cases, the facial asymmetry was slow to manifest over months to years such that it was not noticed by patient or family until pointed out (figure 1).
Hypomimia, the observation of facial bradykinesia and hypokinesia manifesting as a reduced degree of facial spontaneous movement and expressivity,1 is a recognisable feature of PD but typically has bilateral facial involvement rather than being solely—or predominantly—unilateral. While asymmetry of motor symptoms is a diagnostic feature of PD, it is not common to have such striking facial asymmetry so as to mimic facial weakness.
Other differential diagnoses to consider in patients with facial asymmetry and their typical semiologies include seventh cranial nerve pathologies (upper and lower facial paralysis), upper motor neuron pathologies (weakness sparing the upper face), focal dystonia (involuntary spasms), functional weakness or spasm (such as lateral pulling of the lip or jaw) or morphological asymmetries.2
‘Hemihypomimia’ very sparsely appears in the literature, first appearing in 2005 by Zingler et al in which hemihypomimia was described in a single patient that improved following treatment with levodopa and cabergoline.3 Ozekmekçi et al described a prospective series of 204 patients with Hoehn-Yahr (HY) stage 2 PD, of which 11 (6.4%) had non-transient hemifacial hypomimia.4 A recent (September 2019) conference abstract by Kurtis et al investigated hemihypomimia among HY stage I and II PD patients using facial asymmetry in video recordings, and by their methods determined a prevalence of 46.6% compared with background prevalence of 20.6% in age-matched healthy controls.5
Recognition of hemihypomimia, the unilateral exhibition of hypokinesia and bradykinesia on facial musculature, can contribute to the clinical gestalt in the evaluation of PD while informing clinicians that may otherwise suspect a second primary process.
Contributors Each named author has substantially contributed to conducting the underlying research and drafting this manuscript. Additionally, to the best of our knowledge, the named authors have no conflict of interest, financial or otherwise.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement There are no data in this work.
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