Deep brain stimulation for essential tremor: a systematic review.
ABSTRACT Deep brain stimulation (DBS) is a neurosurgical treatment, which has proven useful in treating Parkinson's disease. This systematic review assessed the safety and effectiveness of DBS for another movement disorder, essential tremor. All studies concerning the use of DBS in patients with essential tremor were identified through searching of electronic databases and hand searching of reference lists. Studies were categorized as before/after DBS or DBS stimulation on/off to allow the effect of the stimulation to be analyzed separately to that of the surgery itself. A total of 430 patients who had received DBS for essential tremor were identified. Most of the reported adverse events were mild and could be treated through changing the stimulation settings. Generally, in all studies, there was a significant improvement in outcomes after DBS compared with baseline scores. In addition, DBS was significantly better in testing when the stimulation was turned on, compared with stimulation turned off or baseline. Based on Level IV evidence, DBS is possibly a safe and effective therapy for essential tremor.
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ABSTRACT: To investigate in patients with essential tremor (ET) treated with thalamic/subthalamic deep brain stimulation (DBS) whether stimulation-induced dysarthria (SID) can be diminished by individualized current-shaping with interleaving stimulation (cs-ILS) while maintaining tremor suppression (TS). Of 26 patients screened, 10 reported SID and were invited for testing. TS was assessed by the Tremor Rating Scale and kinematic analysis of postural and action tremor. SID was assessed by phonetic and logopedic means. Additionally, patients rated their dysarthria on a visual analog scale. In 6 of the 10 patients with ET, DBS-ON (relative to DBS-OFF) led to SID while tremor was successfully reduced. When comparing individualized cs-ILS with a non-current-shaped interleaving stimulation (ILS) in these patients, there was no difference in TS while 4 of the 6 patients showed subjective improvement of speech during cs-ILS. Phonetic analysis (ILS vs cs-ILS) revealed that during cs-ILS there was a reduction of voicing during the production of voiceless stop consonants and also a trend toward an improvement in oral diadochokinetic rate, reflecting less dysarthria. Logopedic rating showed a trend toward deterioration in the diadochokinesis task when comparing ON with OFF but no difference between ILS and cs-ILS. This is a proof-of-principle evaluation of current-shaping in patients with ET treated with thalamic/subthalamic DBS and experiencing SID. Data suggest a benefit on SID from individual shaping of current spread while TS is preserved. This study provides Class IV evidence that in patients with ET treated with DBS with SID, individualized cs-ILS reduces dysarthria while maintaining tremor control.Neurology 01/2014; · 8.25 Impact Factor
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ABSTRACT: The presence of a deep brain stimulator (DBS) in a patient with a movement disorder who develops psychiatric symptoms poses unique diagnostic and therapeutic challenges for the treating clinician. Few sources discuss approaches to diagnosing and treating these symptoms. The authors review the literature on psychiatric complications in DBS for movement disorders and propose a heuristic for categorizing symptoms according to their temporal relationship with the DBS implantation process. Psychiatric symptoms after DBS can be categorized as preimplantation, intra-operative/perioperative, stimulation related, device malfunction, medication related, and chronic stimulation related/long term. Once determined, the specific etiology of a symptom guides the practitioner in treatment. A structured approach to psychiatric symptoms in DBS patients allows practitioners to effectively diagnose and treat them when they arise.Neuromodulation 02/2014; · 1.19 Impact Factor
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ABSTRACT: Abstract Some patients may experience tolerance to chronic ventral intermediate (ViM) thalamic deep brain stimulation (DBS), which may include habituation (loss of sustained tremor control over weeks to days after an adjustment) and rebound (a temporary increase in tremor intensity after stopping DBS). We observed an association between these efficacy limiting phenomena with co-morbid demyelinating sensorimotor peripheral neuropathy (MRT-PN). The clinical and treatment characteristics of neuropathy and tremor pre- and post- DBS are described through retrospective chart review of 5 patients with MRT-PN. Programming strategies (number of programming visits/implant years and number of major parameter changes/electrode) were compared in MRT-PN patients to a group of 7 ET patients without neuropathy, who had >4 years continuous follow-up. The presence of habituation and rebound were recorded. All MRT-PN patients had initial good response to DBS followed by habituation and/or rebound of tremor control, some asymmetrically. Compared to ET without neuropathy (mean follow-up 5.83± 0.78 years), MRT-PN patients (mean follow-up 4.90± 3.73years) required more programming visits/year (p = 0.12) and major parameter changes/electrode/implant year (p = 0.03). The presence of neuropathy may alter tremor characteristics and result in temporary re-setting of thalamic oscillatory drive after DBS in MRT-PN patients. Clinicians should be aware of the risk for tolerance to DBS in MRT-PN and patients should be counseled about possible suboptimal sustained tremor control.The International journal of neuroscience 02/2014; · 0.86 Impact Factor