Holmes Tremor with Dystonia after Parietal and Premotor Ischemic Stroke in an Essential Tremor Patient: A Case Report

Holmes tremor (HT) is a rare post-lesional tremor syndrome, typically emerging weeks to months after focal brain injury involving the brainstem, thalamus, or cerebellum. It is characterized by a low-frequency tremor (<5 Hz) present at rest, posture, and during action, often associated with dystonia or other hyperkinetic movement disorders.1 Although more often observed in the limbs, head tremor can occur.2 Historically termed “rubral tremor,” HT has been reported after lesions in diverse anatomical sites, supporting a distributed network basis. Lesion network mapping shows that heterogeneous lesion locations converge on a common tremor circuit linking the red nucleus, thalamus, globus pallidus, and cerebellum.3 Cortical lesions are rarely implicated: one case described a low-frequency action tremor,4 while another was suspected as HT but lacked sufficient imaging to exclude deeper lesions.5 Conversely, dystonia and athetosis are more frequently reported after cortical damage.6 We report the first neurophysiologically confirmed HT following a parietal lesion with additional extension into the premotor cortex, in a patient with pre-existing essential tremor (ET). A 71-year-old woman with a longstanding mild, bilateral and symmetric upper-limb action tremor, consistent with ET, which had begun at 57 years of age, without alcohol responsiveness, and with a positive family history (mother with long-standing upper limb action tremor who later developed Parkinson's disease dementia; one daughter with isolated head tremor), presented in summer 2020 (67 years of age) with acute neurological symptoms. She first experienced a 45-minute episode of dizziness, followed days later by right-hand weakness. A week later, she developed acute right-arm weakness, with preserved speech but gait difficulty. Brain MRI revealed an ischemic lesion involving the left posterior parietal cortex with a small extension into the ipsilateral premotor cortex, visible on both diffusion-weighted and FLAIR sequences (Fig. 1). She was hospitalized, diagnosed with ischemic stroke, and discharged to rehabilitation. On discharge, neurological examination showed a mild hemiparesis and mild hyperpathia of the right arm. Approximately one year later, she developed a more severe tremor of the right arm, which gradually worsened, and head tremor. When she presented at our hospital (in 2024), we observed a tremor of the right upper limb that was present at rest, increased in posture (especially in a wing-beating position), and worsened during action (Video 1). The rest tremor was intermittent, but clearly present also when lying down. There was no distractibility. She also had a mild horizontal head tremor and mild left arm tremor. The right arm showed dystonic posturing, with finger flexion and twisting movements resembling athetosis, which reduced with a sensory trick. Neurological examination also revealed normal tone, mild right-arm paresis, normal coordination as far as assessable despite tremor, no bradykinesia, and mild hyperpathia without proprioceptive deficits. Surface polymyography of the right arm confirmed a tremor frequency of 3.4–3.5 Hz across rest, posture, and kinetic conditions. Dopamine transporter SPECT was normal (Fig. 1). Follow-up MRI in 2024 confirmed the chronic parietal–premotor infarct, without new lesions (Fig. 1). Since the onset of the tremor, the patient has tried tetrabenazine (25 mg twice daily), propranolol (40 mg twice daily), and pregabalin (75 mg once daily), without benefit. Anticholinergic drugs were not prescribed because of mild cognitive deficits and older age. Botulinum toxin injections were administered to the right arm muscles (trapezius, deltoid, biceps, triceps, and wrist flexors), and at follow-up one year later, both tremor and dystonic posturing were reduced. Consent for publication of anonymized clinical details and images was obtained. This case represents the first documented occurrence of HT following a posterior parietal infarct. The associated dystonic posturing is consistent with prior reports that dystonia may accompany HT,7 making alternative classifications less likely. Prior reports of tremor after parietal lesions describe different phenotypes, such as postural tremor without a resting component, or lacked sufficient imaging detail to exclude deeper involvement.4, 5 Our case therefore extends the anatomical spectrum of lesions capable of producing HT. Importantly, the lesion in this patient involved two cortical nodes—posterior parietal and premotor cortex. Both regions are relevant to tremor pathophysiology. Parietal cortex plays a central role in sensorimotor integration, and FDG-PET studies in ET have demonstrated altered parietal metabolism.8 Premotor and supplementary motor areas have been found to be implicated in ET and dystonic tremor, with abnormal oscillatory activity and connectivity to the cerebello–thalamo–cortical circuit.9 It is therefore plausible that parietal involvement disrupted sensory integration pathways, while premotor involvement impaired motor planning, jointly unmasking tremor. Lesion network mapping studies have shown that different lesion sites producing HT converge on a common circuit.3, 10 Our case reinforces this network-based concept: cortical lesions, though remote from the traditional midbrain or thalamic foci, can still produce HT by disrupting connectivity of a tremor-related network within the lesion connectome. This disruption likely generates abnormal activity that differs from the oscillatory patterns seen in ET, which may explain why tremor-modulating agents provided little benefit in this case. The patient's history of mild ET suggests a pre-existing vulnerability of the tremor network. The cortical lesion may have further destabilized this already fragile system, fitting a “double-hit” model. A mild head tremor also developed after the stroke, which may reflect a more extensive expression of the disturbance within the lesion-related tremor circuit. This remains a speculative hypothesis that warrants further study. In conclusion, we describe the first case of HT after a parieto-premotor stroke. This case underscores that HT is a network disorder and that cortical lesions may elicit HT when strategically located within tremor circuits. (1) Research project: A. Conception, B. Organization, C. Execution; (2) Data collection: A. Design, B. Recruitment and Execution, C. Review and Critique; (3) Manuscript preparation: A. Writing of the first draft, B. Review and Critique. L.A.: 1C, 2B, 3A, 3B R.C.G.H.: 1A, 1B, 2A, 2B, 2C, 3B Ethical Compliance Statement: The authors confirm that the approval of an institutional review board was not required for this work. A written informed consent of the patient was obtained for the publication of his data. The authors have read the Journal's position on issues involved in the ethical publication and affirm that this work is consistent with the guidelines. Funding Sources and Conflict of Interest: No specific funding was received for this work. The authors declare that there are no conflicts of interest relevant to this work. Financial Disclosures for the Previous 12 Months: The authors declare that there are no additional disclosures to report. Author disclosures are available in the Supporting Information. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Data S1. COI_disclosure. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.