Gamma knife thalamotomy for disabling tremor: a blinded evaluation.
ABSTRACT Gamma knife thalamotomy (GKT) has been used as a therapeutic option for patients with disabling tremor refractory to medications. Impressive improvement of tremor has been reported in the neurosurgical literature, but the reliability of such data has been questioned.
To prospectively evaluate clinical outcomes after GKT for disabling tremor with blinded assessments.
Prospective study with blinded independent neurologic evaluations.
Consecutive patients who underwent unilateral GKT for essential tremor and Parkinson disease tremor at our center. These patients were unwilling or deemed unsuitable candidates for deep brain stimulation or other surgical procedures.
Unilateral GKT and regular follow-up evaluations for up to 30 months, with blinded video evaluations by a movement disorders neurologist.
Clinical outcomes, as measured by the Fahn-Tolosa-Marin Tremor Rating Scale and activities of daily living scores, and incidence of adverse events.
From September 1, 2006, to November 30, 2008, 18 patients underwent unilateral GKT for essential tremor and Parkinson disease tremor at our center. Videos for 14 patients (11 with essential tremor, 3 with Parkinson disease tremor) with at least 6 months' postoperative follow-up were available for analysis (mean [SD] follow-up duration, 19.2 [7.3] months; range, 7-30 months). The Fahn-Tolosa-Marin Tremor Rating Scale activities of daily living scores improved significantly after GKT (P = .03; median and mean change scores, 2.5 and 2.7 points, respectively [range of scale was 0-27]), but there was no significant improvement in other Fahn-Tolosa-Marin Tremor Rating Scale items (P = .53 for resting tremor, P = .24 for postural tremor, P = .62 for action tremor, P = .40 for drawing, P > .99 for pouring water, P = .89 for head tremor). Handwriting and Unified Parkinson's Disease Rating Scale activities of daily living scores tended to improve (P = .07 and .11, respectively). Three patients developed delayed neurologic adverse events.
Overall, we found that GKT provided only modest antitremor efficacy. Of the 2 patients with essential tremor who experienced marked improvement in tremor, 1 subsequently experienced a serious adverse event. Further prospective studies with careful neurologic evaluation of outcomes are necessary before GKT can be recommended for disabling tremor on a routine clinical basis.
Article: Gamma Knife for Functional Diseases.Journal of the American Society for Experimental NeuroTherapeutics 06/2014; 11(3). DOI:10.1007/s13311-014-0276-z · 3.88 Impact Factor
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ABSTRACT: Tremor is a hyperkinetic movement disorder characterized by rhythmic oscillations of one or more body parts. Disease severity ranges from mild to severe with various degrees of impact on quality of life. Essential tremor and parkinsonian tremor are the most common etiologic subtypes. Treatment may be challenging; although several drugs are available, response may be unsatisfactory. For some tremor forms, controlled data are scarce or completely missing and treatment is often based on anecdotal evidence. In this article, we review the current literature on tremor treatment, with a focus on common forms. Copyright © 2015 Elsevier Inc. All rights reserved.Neurologic Clinics 02/2015; 33(1):57-75. DOI:10.1016/j.ncl.2014.09.005 · 1.61 Impact Factor
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ABSTRACT: Parkinson's disease (PD) is the second most common neurodegenerative disorder; the safety and effects of radiation therapy on PD are not well established. We report a patient with PD and a brain tumor referred for radiation therapy and review the literature on this topic focusing on the incidence of cancer and brain tumors in PD, brain tumors and radiation therapy as independent causes of PD, and the safety and effect of radiation therapy, including functional radiosurgery, in patients with PD. A PubMed literature review focusing on all English language publications from 1940 to 2014 identified 146 relevant articles, of which 91 discussed functional radiosurgery for PD, 49 discussed "neoplastic parkinsonism," 4 discussed radiation-induced parkinsonism, and 2 discussed the safety of fractionated radiation therapy in patients with PD. Odds ratios of 0.4 to 0.88 have been reported for the development of cancer in general among patients with PD, whereas the incidence ratios of PD patients developing a brain tumor relative to the general population range from 0.9 to 1.61. Parkinsonian symptoms thought to arise as a sequelae of tumor growth have been described in 49 papers dating to 1953. We identified 4 reports of parkinsonian syndromes that arose after radiation therapy, comprising a total of 7 patients, including 5 adults and 2 pediatric patients. Pediatric patients showed a mixed response to dopamine agonist therapy, whereas adults had little symptom improvement. Reports of PD patients irradiated in conventional fractionation for a variety of indications do not appear to indicate increased sensitivity to radiation therapy or exacerbated PD symptoms after irradiation. Radiosurgery performed for management of refractory tremor in PD patients results in up to an 88% favorable outcome, with the onset of symptom improvement ranging from 3 days to 1 year and minimal toxicity (not exceeding the toxicities observed for the same stereotactic radiosurgery procedure performed for essential tremor in nonparkinsonian patients). Patients with PD do not harbor an increased risk for the development of cancer in general and have similar incidence of brain tumors as the general population. Tumor-induced parkinsonism is a rare entity. Parkinsonism as a side effect of brain radiation is an uncommon phenomenon, even after high doses, but is associated with limited response to medical management. Rare cases in children, typically associated with bilateral imaging changes, have been described, which suggests possible uncommon genetic predisposition. There are no convincing reports that suggest that pre-existing parkinsonism is worsened by radiation therapy, although a mechanistic possibility for this exists. Functional radiosurgery for management of refractory tremor in PD patients is safe and effective. Radiation therapy, either fractionated or stereotactic radiosurgery, appears to be safe when used judiciously for patients with PD, for the treatment of either tumors or PD itself. Copyright © 2014. Published by Elsevier Inc.02/2015; DOI:10.1016/j.prro.2014.12.001