(99m)Tc-TRODAT-1 SPECT study in evaluation of Holmes tremor after thalamic hemorrhage

Analysis of Semiology, Lesion Topography and Treatment Outcomes: A Prospective Study on Post Thalamic Stroke Holmes Tremor

OBJECTIVE

Holmes tremor (HT) comprises rest, postural and intention tremor subtypes, usually involving both proximal and distal musculature. Perturbations of nigro-striatal pathways might be fundamental in the pathogenesis of HT along with cerebello-thalamic connections.

METHODS

Nine patients with an HT phenotype secondary to thalamic stroke were included. Epidemiological and clinical records were obtained. Structural and functional brain imaging were performed with magnetic resonance imaging (MRI) or computed tomography (CT) and positron emission tomography (PET), respectively. Levodopa was administered in sequentially increasing dosage, with various other drugs in case of inadequate response. Longitudinal follow-up was performed for at least three months. The essential tremor rating assessment scale (TETRAS) was used for assessment.

RESULTS

The mean latency from stroke to tremor onset was 50.4 ± 30.60 days (range 21-90 days). Dystonia was the most frequently associated hyperkinetic movement (88.8%). Tremor was bilateral in 22.2% of participants. Clinical response was judged based on a reduction in the TETRAS score by a prefixed value (≥ 30%), pertaining to which 55.5% (n = 5) of subjects were classified as responders and the rest as non-responders. The responders showed improvement with significantly lower doses of levodopa than the remaining nonresponders (240 ± 54.7 mg vs. 400 ± 40.8 mg; p = 0.012).

CONCLUSION

Although levodopa is useful in HT, augmenting the dosage of levodopa beyond a certain point might not benefit patients clinically. Topography of vascular lesions within the thalamus might additionally influence the phenomenology of HT.

Post-stroke Movement Disorders: Clinical Spectrum, Pathogenesis, and Management

Involuntary movements develop after 1-4% of strokes and they have been reported in patients with ischemic and hemorrhagic strokes affecting the basal ganglia, thalamus, and/or their connections. Hemichorea-hemiballism is the most common movement disorder following a stroke in adults while dystonia is most common in children. Tremor, myoclonus, asterixis, stereotypies, and vascular parkinsonism are other movement disorders seen following stroke. Some of them occur immediately after acute stroke, some can develop later, and others may have delayed onset progressive course. Proposed pathophysiological mechanisms include neuronal plasticity, functional diaschisis, and age-related differences in brain metabolism. There are no guidelines regarding the management of post-stroke movement disorders, mainly because of their heterogeneity.

Brain 123I-FP-CIT SPECT of a Holmes Tremor Due to Midbrain Pilocytic Astrocytoma

A 24-year-old woman with an unresectable right mesencephalic pilocytic astrocytoma was treated with stereotaxic radiation therapy. Three months after a radiation therapy-induced bleeding, she presented a severe disabling low frequency rest and kinetic tremor involving the left upper limb, associated with dystonia, and a Holmes tremor was suspected. Thereby, we performed a I-FP-CIT SPECT (DATSCAN) that revealed a normal distribution of radiotracer over the left striatum, whereas no binding was seen in the right caudate and putamen. This pattern was consistent with a right severe nigrostriatal dopaminergic denervation due to an ipsilateral red nucleus injury.

Tremor Secondary to a Thalamic Glioma: A Case Report

BACKGROUND AND IMPORTANCE

Tremor is the most prevalent movement disorder. While the exact pathophysiology remains to be elucidated, the importance of the thalamus in tremor circuitry is well recognized. Thalamic lesions from demyelination, trauma, ischemia, or neoplasm rarely cause isolated tremor. We report the case of a patient presenting with a tremor secondary to a thalamic grade II astrocytoma that improved with treatment.

CLINICAL PRESENTATION

A 50-yr-old male presented with a 1-yr history of right-hand tremor. The presence of long tract signs prompted imaging that revealed a lesion within the left thalamus. Stereotactic biopsy revealed a World Health Organization grade II astrocytoma. Prior to biopsy, the patient's tremor was graded using the Clinical Rating Scale for Tremor. Immediately postoperatively the patient remained at his neurological baseline without improvement in his tremor. Subsequent fractionated radiotherapy with concomitant temozolomide followed by adjuvant temozolomide led to radiographic response as well as clinical improvement. The patient reported less tremor, which was confirmed objectively with improved Clinical Rating Scale for Tremor scores at 6 and 12 mo postoperatively.

CONCLUSION

This case of a thalamic glioma presenting with isolated contralateral tremor highlights the role of the thalamus in the development of tremor. Moreover, this particular case contrasts with other published reports on the lack of additional symptoms and tremor response to chemoradiation.

Degeneration of paramedian nuclei in the thalamus induces Holmes tremor in a case of artery of Percheron infarction

RATIONALE

Holmes' tremor is an uncommon neurologic disorder following brain insults, and its pathogenesis is undefined. The interruption of the dento-rubro-thalamic tract and secondary deterioration of the nigrostriatal pathway are both required to initiate Holmes' tremor. We used nuclear medicine imaging tools to analyze a patient with concurrent infarction in different zones of each side of the thalamus. Finding whether the paramedian nuclear groups of the thalamus were injured was a decisive element for developing Holmes' tremor.

PATIENT CONCERNS

A 36-year-old woman was admitted to our department due to a bilateral paramedian thalamic infarction. Seven months after the stroke, a unilaterally involuntary trembling with irregularly wavering motions occurring in both her left hand and forearm.

DIAGNOSIS

Based on the distinct features of the unilateral coarse tremor and the locations of the lesions on the magnetic resonance imaging (MRI), the patient was diagnosed with bilateral paramedian thalamic infarction complicated with a unilateral Holmes' tremor.

INTERVENTIONS

The patient refused our recommendation of pharmacological treatment with levodopa and other dopamine agonists based on personal reasons and was only willing to accept physical and occupational training programs at our outpatient clinic.

OUTCOMES

We utilized serial anatomic and functional neuroimaging of the brain to survey the neurologic deficit. A brain magnetic resonance imaging showed unequal recovery on each side of the thalamus. The residual lesion appeared larger in the right-side thalamus and had gathered in the paramedian area. A brain perfusion single-photon emission computed tomography (SPECT) revealed that the post-stroke hypometabolic changes were not only in the right-side thalamus but also in the right basal ganglion, which was anatomically intact. Furthermore, the brain Technetium-99m-labeled tropanes as a dopamine transporter imaging agents scan ( Tc-TRODAT-1) displayed a secondary reduction of dopamine transporters in the right nigrostriatal pathway which had resulted from the damage on the paramedian nuclear groups of the right-side thalamus.

LESSONS

Based on the functional images, we illustrated that a retrograde degeneration originating from the thalamic paramedian nuclear groups, and extending forward along the direct innervating fibers of the mesothalamic pathway, played an essential role towards initiating Holmes' tremor.

Is nigrostriatal dopaminergic deficit necessary for Holmes tremor to develop? The DaTSCAN and IBZM SPECT study

Holmes’s tremor (HT) is assumed to be the result of coexistence of nigrostriatal dopaminergic system impairment and the lesion of cerebello-thalamic pathways. It was suggested that dopaminergic deficiency is responsible for rest tremor, and lack of compensatory cerebellar function leads to spill of tremor into voluntary movements. Cases of HT with and without abnormalities of the presynaptic part of dopaminergic nigrostriatal were published and these findings raised the question of possibility of the postsynaptic lesion. Three patients with HT diagnosed according to criteria of Consensus Statement on Tremor were studied. In all of them SPECT imaging with ligands of presynaptic (I 123-FP CIT—DaTSCAN) and postsynaptic (I 123-iodobenzamide—IBZM) nigrostriatal dopaminergic neurons was performed. Indices of uptake in caudate and putamen normalized to nonspecific uptake in occipital cortex and indices of asymmetry for each whole striatum as well as for putamen and caudate separately were calculated. SPECT studies did not reveal asymmetry of DaTSCAN and IBZM binding in striatum in all studied subjects. The current clinical diagnostic criteria of HT are presumably insufficiently specific and when using them we identify patients both with and without the involvement of dopaminergic system. These two groups may represent tremor disorders of similar phenomenology but of different pathomechanism.

Levodopa-responsive Holmes' Tremor Caused by a Single Inflammatory Demyelinating Lesion

BACKGROUND

Holmes' tremor is characterized by a combination of rest, postural, and kinetic tremor that is presumably caused by interruption of cerebello-thalamo-cortical and nigrostriatal pathways. Medical treatment remains unsatisfactory.

CASE REPORT

A 16-year-old girl presented with Holmes' tremor caused by a transient midbrain abnormality on magnetic resonance imaging (MRI). To explore the discrepancy between persistent tremor and resolved MRI changes, we performed dopamine transporter single-photon emission computed tomography (DaT-SPECT) with a 123I-ioflupane that revealed nearly absent DaT binding in the right striatum. Levodopa dramatically improved the tremor.

DISCUSSION

This is only the second report of a transient midbrain MRI abnormality disrupting nigrostriatal pathways. The case highlights the sometimes limited sensitivity of morphologic imaging for identifying the functional consequences of tissue damage and confirms that DaT imaging may serve as a predictor for levodopa responsiveness in Holmes' tremor.

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.

Movement disorders after stroke in adults: a review

Background

Movement disorders occur in association with stroke and may have important clinical implications.

Methods

We reviewed the medical literature regarding the clinical phenomenology, prevalence, localization and etiologic implications, and treatments for movement disorders occurring after stroke in adult patients.

Results

Movement disorders occur uncommonly after stroke and include both hyperkinetic and parkinsonian conditions. They can occur at the time of stroke or appear as a later manifestation. Stroke lesions are typically due to small vessel cerebrovascular disease in the middle or posterior cerebral artery territory, vessels supplying the basal ganglia. Hemorrhagic lesions are more likely to induce hyperkinetic movements. Movement disorders in the setting of stroke tend to resolve spontaneously over time. Medical and surgical therapies are available to treat the movement problems.

Discussion

Movement disorders after stroke can be helpful in localizing lesions after stroke, determining the etiology of stroke, may need to be a target for therapy and may importantly influence long term outcome.

Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits?

Tremor in Parkinson's disease has several mysterious features. Clinically, tremor is seen in only three out of four patients with Parkinson's disease, and tremor-dominant patients generally follow a more benign disease course than non-tremor patients. Pathophysiologically, tremor is linked to altered activity in not one, but two distinct circuits: the basal ganglia, which are primarily affected by dopamine depletion in Parkinson's disease, and the cerebello-thalamo-cortical circuit, which is also involved in many other tremors. The purpose of this review is to integrate these clinical and pathophysiological features of tremor in Parkinson's disease. We first describe clinical and pathological differences between tremor-dominant and non-tremor Parkinson's disease subtypes, and then summarize recent studies on the pathophysiology of tremor. We also discuss a newly proposed ‘dimmer-switch model’ that explains tremor as resulting from the combined actions of two circuits: the basal ganglia that trigger tremor episodes and the cerebello-thalamo-cortical circuit that produces the tremor. Finally, we address several important open questions: why resting tremor stops during voluntary movements, why it has a variable response to dopaminergic treatment, why it indicates a benign Parkinson's disease subtype and why its expression decreases with disease progression.