Long-Term Patient-Reported Outcome of Radiofrequency Thalamotomy for Tremor.

BACKGROUND: Thalamotomy is an endorsed treatment for medication-refractory tremor. It used to be the standard, but nowadays deep brain stimulation (DBS) has become the treatment option of choice. Nevertheless, DBS has the disadvantage of hardware failure, battery replacement, and frequent setting adjustment. Radiofrequency (RF) thalamotomy lacks these issues, is relatively inexpensive, and has a broad applicability in patients with significant comorbidity. Therefore, we analyzed the long-term patient-reported outcome of RF thalamotomy in a cohort of patients with an otherwise intractable tremor. METHODS: A single-center cohort of 27 consecutive patients with intractable tremor was assessed after unilateral RF thalamotomy. Over time, 4 patients had died because of non-related causes. In total, 21 patients responded to a telephone survey to assess their personal judgment on postoperative tremor severity, using a validated tremor scale, adverse events, recurrence, and patient satisfaction. The median time between surgery and telephone survey was 39 months (range 12-126). Seven patients had an additional analysis with postoperative imaging, video-assisted electromyography tremor registration, and a self-reported treatment effect (SRTE) assessment. RESULTS: Nineteen out of 21 patients (90.5%) reported absence or significant improvement of their tremor. The rating score (WHIGET/UPDRS-III) dropped significantly from a mean of 3.57 preoperatively to 1.05 postoperatively (p < 0.001). Eleven patients (52.4%) reported adverse events, but the majority (76.2%) did not consider the adverse events to be severe. SRTE assessment showed a direct postoperative effect of 89.6 of 100 points (SD 10.8), with a gradual decrease to 75.3 (SD 23.5) during follow-up. CONCLUSIONS: RF thalamotomy is a very effective long-term treatment for medication-refractory tremor and should therefore be considered in patients with a refractory unilateral tremor.

Therapeutic potential of deep brain stimulation of the nucleus accumbens in morbid obesity.

OBJECTIVE Morbid obesity is a growing problem worldwide. The current treatment options have limitations regarding effectiveness and complication rates. New treatment modalities are therefore warranted. One of the options is deep brain stimulation (DBS) of the nucleus accumbens (NAC). This review aims to summarize the current knowledge on NAC-DBS for the treatment of morbid obesity. METHODS Studies were obtained from multiple electronic bibliographic databases, supplemented with searches of reference lists. All animal and human studies reporting on the effects of NAC-DBS on body weight in morbidly obese patients were included. Articles found during the search were screened by 2 reviewers, and when deemed applicable, the relevant data were extracted. RESULTS Five relevant animal experimental papers were identified, pointing toward a beneficial effect of high-frequency stimulation of the lateral shell of the NAC. Three human case reports show a beneficial effect of NAC-DBS on body weight in morbidly obese patients. CONCLUSIONS The available literature supports NAC-DBS to treat morbid obesity. The number of well-conducted animal studies, however, is very limited. Also, the optimal anatomical position of the DBS electrode within the NAC, as well as the optimal stimulation parameters, has not yet been established. These matters need to be addressed before this strategy can be considered for human clinical trials.

Substituting the Target After Unsatisfactory Outcome of Deep Brain Stimulation in Advanced Parkinson's Disease: Cases From the NSTAPS Trial and Systematic Review of the Literature.

BACKGROUND: Deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and the subthalamic nucleus (STN) are established treatment option in Parkinson's disease (PD). If DBS does not provide the desired effect, re-operation to the alternative target is a treatment option, but data on the effect of re-operation are scarce. OBJECTIVES: The objective of this study is to evaluate the clinical effect of re-operation the alternative target after failure of initial STN or GPi DBS for Parkinson's disease. MATERIALS AND METHODS: We descriptively analyzed the baseline characteristics, the effect of initial surgery and re-operation of eight NSTAPS (Netherlands SubThalamic and Pallidal Stimulation) patients and six previously published cases that underwent re-operation to a different target. RESULTS: In the NSTAPS cohort, two of the eight patients showed more than 30% improvement of off-drug motor symptoms after re-operation. The initial DBS leads of these patients were off target. In the cases from the literature, 30% off-drug motor improvement was seen in all three patients re-operated from GPi to STN and none of the three patients re-operated from STN to GPi. Only one of the three cases from the literature where any improvement was seen with the operation had a confirmed on target lead location after the first surgery, while the other two patients did not undergo post-operative imaging after the first surgery. CONCLUSIONS: Re-operation to a different target due to lack of effect appears to have a limited chance of leading to objective improvement if the leads were correctly placed during initial surgery.

Effect of Direct Stimulation of the Cochleovestibular Nerve on Tinnitus: A Long-Term Follow-Up Study.

OBJECTIVE: Tinnitus is a common entity that may lead to severe impairment in quality of life. An adequate treatment modality for severe tinnitus is currently lacking. Neurostimulation of the auditory tract may serve as a promising adjunct in tinnitus treatment. The aim is to investigate the effect of direct stimulation on the cochleovestibular nerve for intractable tinnitus. METHODS: This study was conducted at the University Medical Center Groningen, The Netherlands. We studied 10 patients with severe, unilateral, intractable tinnitus, who were implanted with a cuff electrode around the cochleovestibular nerve between 2001 and 2013. All patients had preoperative ipsilateral hearing loss. Tinnitus Handicap Inventory (THI) scores and audiometric values were collected. Treatment success was determined based on the self-assessment of satisfactory usage by each patient. RESULTS: The mean preoperative tinnitus duration was 8.0 ± 5.9 years. The preoperative THI score was 71 ± 18 points. During mean follow-up of 49 months, the mean THI reduction was 24 ± 26 points (P = 0.02). Treatment was regarded successful in 6 patients (60%). In these patients, tinnitus did not disappear, but transformed into a more bearable sound. In 4 patients, transient complications occurred, and 1 patient experienced permanent vertigo postoperatively. Furthermore, hearing deterioration was a result of implantation in 86% of the patients. CONCLUSIONS: Direct neurostimulation resulted in treatment success in a small majority of the patients, with a significant decrease in THI score. However, because of a high risk of additional hearing damage, this technique seems not viable for patients with moderate hearing loss.

Modulation of cerebral blood flow with transcutaneous electrical neurostimulation (TENS) in patients with cerebral vasospasm after subarachnoid hemorrhage.

OBJECTIVES: Transcutaneous electrical neurostimulation (TENS) and spinal cord stimulation have been shown to increase peripheral and cerebral blood flow. We postulate that certain pathological conditions attenuate cerebral autoregulation, which may result in a relative increase of the importance of neurogenic regulation of cerebral blood flow, which could be decreased by electrical modulation. We therefore assess the effects of TENS on cerebral blood flow velocities (CBFVs) and cerebral saturation in patients with cerebral vasospasm after subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: Cervical TENS was applied in 10 SAH patients with transcranial Doppler (TCD)-proven cerebral vasospasm. Measurements included plethysmography, near-infrared spectroscopy, capnography, and CBFVs by TCD. After determining the optimal frequency and current, patients were treated with cervical TENS for two periods of three days, with a pause of one day in between. RESULTS: The TENS electrodes were not always tolerated by the patients. Higher frequencies demonstrated the most prominent combined effects. ETCO2 was 0.19% lower with TENS off than with TENS on (p = 0.05). Mean arterial blood pressure and pulse were not significantly different over time. CBFV in MCA was decreased (p = 0.07) while cerebral oxygen saturation was increased (p = 0.01) after the use of TENS. CONCLUSIONS: Our data suggest improved cerebral blood flow when using cervical TENS in patients with cerebral vasospasm. Several factors could have attenuated the effects: the electrodes were poorly tolerated, ETCO2 increased during TENS, few vessels showed prolonged vasospasm, and overall flow velocities were low. Still, an on-off effect of TENS over time was detected.

The influence of transcutaneous electrical neurostimulation (TENS) on human cerebral blood flow velocities.

BACKGROUND: It has been shown that transcutaneous electrical neurostimulation (TENS) reduces sympathetic tone. Spinal cord stimulation (SCS) has proven qualities to improve coronary, peripheral, and cerebral blood circulation. Therefore, we postulate that TENS and SCS affect the autonomic nervous system in analogous ways. In this line of thought, cervical application of TENS might be a useful and simple adjunct in the treatment of cerebrovascular disease by improving cerebral blood flow. Experiments were performed in order to assess whether cervical TENS is safe and whether an effect on cerebral blood flow velocity (CBFV) can be shown in healthy subjects. METHOD: A controlled, non-randomized, phase 1 study was performed with 20 healthy volunteers. Cervical TENS was applied in several frequencies, with and without hyperventilation. Continuous registration of blood pressure, pulse, CBFV (estimated by transcranial Doppler sonography) and end-tidal carbon dioxide concentration was performed. FINDINGS: Cervical TENS was well-tolerated by all subjects. Despite small effects on heart rate (HR) and mean arterial blood pressure (MAP), a significant effect on middle cerebral artery (MCA) blood flow velocity was not demonstrated. No effect of age, gender, current or session order on MCA, HR, or MAP was found. TENS did not influence the effect of hyperventilation. CONCLUSIONS: In these experiments, application of cervical TENS is proven to be a safe procedure. However, no effects on cerebral blood flow velocity could be detected, perhaps due to the intact cerebral autoregulation in the healthy volunteers.