TABLE 1.

Clinical and radiological spectrum of COVID‐19 associated de novo movement disorders

Author(s)	Age (y)/sex	Type of movement disorder(s)	Neuromaging/Electroencephalogram (EEG)	Therapy for movement disorder	Outcome	Time to movement disorder onset	CSF PCR for SARS‐CoV‐2	Autoimmune encephalitis panel
Khoo et al. 35	65 / Woman	Generalized myoclonus, ocular flutter, ocular‐facial‐synkinesis, convergence spasm and acquired hyperekplexia	Normal / Normal EEG	Levetiracetam, clonazepam and corticosteroids	Improvement	Seven days	Negative	Negative
Lechien et al. 36	28 / Woman	Inspiratory and expiratory paradoxical movement of the vocal folds	Not performed	Speech therapy	Recovery after four months	Seven weeks	Not performed	Not performed
Dijkstra et al. 37	44 / Man	Generalized, stimulus‐sensitive myoclonus, transient ocular flutter and cerebellar ataxia	Normal / Not available	Intravenous corticosteroids and immunoglobulins	Full recovery after two months	Two weeks	Negative	Negative
Anand et al. 38	Multicenter case series (eight patients)	Myoclonus (mostly stimulus sensitive; in one case it was spontaneous)	Normal in most cases/EEG was performed in most cases ranging from background slowing, transient bifrontal sharp waves to generalized dysfunction	Levetiracetam, clonazepam, valproate, dexmedetomidine (most cases), ketamine, lorazepam and primidone	One patient died. In five cases, myoclonus completely resolved while in three cases, it persisted for 10 days or longer.	Variable	Negative	Not performed
Cohen et al. 39	45 / Man	Asymmetric (right>left) tremor in legs, increased urinary frequency, micrography, hypomimia, bradykinesia and cogwheel rigidity	Normal brain magnetic resonance imaging. Positron emission tomography (PET) scan showed decreased 18F‐FDOPA uptake in both putamina, more apparent on the left side. Additionally, mild decreased uptake in the left caudate was also suspected / Normal EEG	Corticosteroids, pramipexole and biperidin	Persistence of symptoms	Three to four weeks	Negative	Negative
Faber et al. 40	35 / Woman	Generalized and asymmetric (right>left) bradykinesia, cogwheel rigidity, stooped posture, reduced arm swing, enbloc turning, and decreased stride length.	Normal magnetic resonance imaging and PET scans; decreased dopamine transporter (DAT) density on the left putamen (more evident in the mid‐putamen, different from the posterior involvement usual of idiopathic Parkinson's disease)/EEG not available	Levodopa/benserazide	Significant improvement with anti‐parkinsonian drugs	Two to four weeks	Negative	Negative
Cuhna P et al. 41	Case series (five patients)	Upper limbs postural and action‐tremor in four patients; one of them had also irregular orthostatic tremor, another one bilateral upper limbs jerky/myoclonic abnormal movements at rest and during posture and action	Magnetic resonance imaging in four patients showed microbleeds and a bilateral frontotemporal hypoperfusion in one patient. Neuromelanin‐sensitive magnetic resonance imaging showed dorsal‐nigral hyperintensity bilaterally in all, but one. 123I‐FP‐CIT single photon emission computed tomography performed in four patients was normal / not performed	None	Not performed	Two to five weeks	Not performed	Not performed
Mas Serrano et al. 42	Case series (two patients)	Myoclonus (multi‐focal) and ocular clonus	Normal neuroimaging in both cases/EEG showed diffuse encephalopathy in both cases	None	Improvement to baseline	One to two weeks	Not performed	Not performed
Diezma‐Martín et al. 43	70 / M	Tremor and ataxia	Normal / Not performed	Clonazepam	Improved after one moth of discharge	Two to five weeks	Negative	Negative
Rábano‐Suárez et al. 44	Case series (three patients)	Stimulus sensitive generalized myoclonus	Normal / EEG showed diffuse background slowing	Dexmedetomidine, clonazepam, valproate, levetiracetam, propofol, corticosteroids and plasmapheresis	Improved	Two weeks	Negative	Negative
Balestrino et al. 45	73 / Man	Ataxia	Normal / EEG showed reactive, unstable, symmetrical background alpha activity in posterior regions; sporadic, low‐voltage, focal polymorph delta elements in the anterior‐frontal left cortex and sporadic spikes without clear epileptic correlate in the frontotemporal lobe, predominantly on the left	None	Improved after several weeks	One to two weeks	Not performed	Not performed
Méndez‐Guerrero et al. 46	57 / Man	Myoclonus, tremor, parkinsonism and vertical ocular movement abnormalities	DAT‐ single photon emission computed tomography showed bilateral decrease in presynaptic dopamine uptake asymmetrically involving both putamina / EEG showed diffuse mild and reactive slowing	No specific therapy	Improved to baseline within three weeks	40 days	Negative	Negative
Chaumont et al. 47	Case series (four patients)	Upper limbs myoclonus	Normal MRI except recent stroke in case 1 / EEG showed global slowing in patients 1, 2, and 3; and normal in patient 4	Intravenous immunoglobulins and methylprednisolone	Some improvement	Variable	Negative	Not performed
Schellekens et al. 48	48/Man	Myoclonus and cerebellar ataxia	Normal / EEG was not performed	Levetiracetam	Improved	Variable	Negative	Not performed
Paterson et al. 49	Case series (seven patients)	Ataxia and bilateral intention tremor in one patient	Normal in five; multiple large lesions in periventricular white matter of both cerebral hemispheres in one and mild to moderate small vessel disease in another one / EEG was not performed	Intravenous immunoglobulin and corticosteroids	Four cases recovered incompletely an three completely	Variable	Negative in four and not performed in three	Not performed in four; matched oligoclonal bands in serum in two; and negative in one
Piscitelli et al. 50	39/Woman	Lower limbs tremor and ataxia	Normal magnetic resonance imaging/EEG was not performed	Benzodiazepines	No improvement	11 days	Not performed	Not performed
Grimaldi et al. 51	72/Woman	Cerebellar syndrome and myoclonus	18F‐FDG‐PET showed diffuse cortical hypometabolism, associated with putaminal and cerebellum hypermetabolism / EEG showed symmetric bilateral background slowing	Intravenous corticosteroids	Rapid improvement	12 days	Negative	High titers of autoantibodies directed against nuclei of Purkinje cells, as well as to striatal and hippocampal neurons were detected
Borroni B et al. 52	Two cases (54 / Woman and 80 / Man)	Diaphragmatic myoclonus	Normal / EEG was normal in case 1 and lateralized periodic discharges synchronous and asynchronous with the diaphragmatic myoclonic movements in case 2	Clonazepam in case 1 and levetiracetam in case 2	Improvement	Two weeks in case 1 and one month in case 2	Negative	Not performed
Shah et al. 53	Middle aged male	Opsoclonus, cortical myoclonus, symmetric cerebellar ataxia of speech, limbs, trunk and gait	Normal / Not available	Corticosteroids, levetiracetam, valproate and clonazepam	Improvement	Three weeks	Negative	Negative
Muccioli et al. 54	58 / Man	Subcortical myoclonus	Chronic small vessel disease / Normal EEG	Corticosteroids, levetiracetam and clonazepam	Improvement	12 days	Negative	Negative
Ros‐Castelló et al. 55	72 / Woman	Myoclonus	Cortical and brainstem small vessel disease / Normal EEG	Clonazepam	Improvement	Five days	Not performed	Not performed
Emamikhah et al. 56	Case series (seven patients)	Opsoclonus‐myoclonus syndrome and voice tremor	Normal (in one, it was not performed) / EEG was normal in one patient and not performed in the rest	Levetiracetam, valproate, clonazepam, intravenous immunoglobulins and dexamethasone	Recovery (partial for three patients; complete for two patients); one lost to follow‐up; and one under treatment	Variable	Negative for two and not performed for rest	Negative for one and not performed for the rest