Palatal myoclonus in a patient with a lateral thalamic infarction

Post-Thalamic Stroke Movement Disorders: A Systematic Review

BACKGROUND

After a stroke, movement disorders are rare manifestations mainly affecting the deep structures of the brain like the basal ganglia (44%) and thalamus (37%), although there have been case studies of movement disorders in strokes affecting the cerebral cortex also.

SUMMARY

This review aims to delineate the various movement disorders seen in association with thalamic strokes and tries to identify the location of the nuclei affected in each of the described movement disorders. Cases were identified through a search of PubMed database using different search terms related to post-thalamic stroke movement disorders and a secondary search of references of identified articles. We reviewed 2,520 research articles and only 86 papers met the inclusion criteria. Cases were included if they met criteria for post-thalamic stroke movement disorders. Case-cohort studies were also reviewed and will be discussed further. Key Messages: The most common post-stroke abnormal movement disorder reported in our review was dystonia followed by hemiataxia. There was a higher association between ischaemic stroke and movement disorder. Acute onset movement disorders were more common than delayed. The posterolateral thalamus was most commonly involved in post-thalamic stroke movement disorders.

Deterioration of palatal myoclonus after acute thalamic hemorrhage

Background

Palatal myoclonus (PM) is the hallmark of hypertrophic olivary degeneration (HOD); however, little is known regarding the association of thalamic lesions and PM. Case presentation: Here, we report a case of deteriorative PM after an acute small ventrolateral thalamic hemorrhage in a female Chinese patient with HOD. The sudden and severe deterioration of PM was preceded by at least 10 days of an occasionally occurring PM, which was related to an acute cerebellar hemorrhage 8 months earlier. A computed tomography scan upon admission showed a small intracerebral hematoma in the left ventrolateral thalamus, and a magnetic resonance imaging scan revealed the typical signs of HOD as well as a remote lesion in the dentate nucleus. Symptoms of PM were controlled by carbamazepine and clonazepam.

Conclusion

These findings indicated that the damaged dentatothalamic tract might be due to a unique pathogenic mechanism involving a lesion of the ventrolateral thalamus and Guillain-Mollaret triangle.

Movement disorders in cerebrovascular disease

Movement disorders can occur as primary (idiopathic) or genetic disease, as a manifestation of an underlying neurodegenerative disorder, or secondary to a wide range of neurological or systemic diseases. Cerebrovascular diseases represent up to 22% of secondary movement disorders, and involuntary movements develop after 1-4% of strokes. Post-stroke movement disorders can manifest in parkinsonism or a wide range of hyperkinetic movement disorders including chorea, ballism, athetosis, dystonia, tremor, myoclonus, stereotypies, and akathisia. Some of these disorders occur immediately after acute stroke, whereas others can develop later, and yet others represent delayed-onset progressive movement disorders. These movement disorders have been encountered in patients with ischaemic and haemorrhagic strokes, subarachnoid haemorrhage, cerebrovascular malformations, and dural arteriovenous fistula affecting the basal ganglia, their connections, or both.

Top of the basilar artery embolic stroke and neonatal myoclonus

Cerebellar stroke has been virtually unreported in the living newborn infant. A term newborn male weighing 3380g at birth suffered myoclonic seizures within 24 hours of birth by spontaneous vaginal delivery. Apgar scores were 3 and 4 at 1 and 5 minutes. Myoclonus persisted for 9 days, responding poorly to step-up anticonvulsant treatment including lidocaine, midazolam, and clonazepam. Imaging documented arterial ischaemic stroke within the left posterior cerebral and both superior cerebellar arteries, compatible with top of the basilar artery stroke. There was no electrographic correlate for the seizures. Disturbed oscillation within the dentato-rubro-olivary circuitry was the likely mechanism. The probable cause was embolism from an in-utero-onset inferior caval vein thrombosis. At 22 months the child was sitting unsupported. Scores on the Bayley Scales of Infant Development II were equivalent to those of a 12-month/year-old. He showed ataxic motor behaviour. Embolism can cause neonatal top of the basilar artery stroke, which may present with myoclonus due to cerebellar injury.

Cerebral glucose metabolism in oculopalatal tremor

No study adopted the statistical parametric mapping (SPM) analyses of (18)F-fluorodeoxy glucose (FDG) PET in a large number of patients with oculopalatal tremor (OPT). To determine regional cerebral glucose metabolism in patients with OPT, nine patients with OPT underwent FDG-PET of the brain. Their glucose metabolism was compared with that of 50 normal controls (NC) by using SPM analyses. Three patients had bilateral and six showed unilateral pseudohypertrophic degeneration of the inferior olivary nucleus (ION) on MRI. Compared with NC, OPT patients did not show any metabolic derangement in the anterolateral medulla where the pseudohypertrophic ION locates. Instead, six patients with unilateral ION changes had hypometabolism in ipsilesional pontine tegmentum and hypermetabolism in contralesional thalamus. Their metabolic changes did not depend on the lateralization of ION changes. Our study failed to present any metabolic evidence for the role of ION in the generation of OPT. In part, the failure might originate from the different pathomechanism between OPT and pure palatal tremor or sensitivity/specificity issues of PET and SPM analyses. But, our results suggest that impaired cell groups of the paramedian tract and thalamic tremor cells may contribute to the generation of OPT.