Outcomes Of Deep Brain Stimulation Surgery Research Articles

Patient Evaluation and Selection for Movement Disorders Surgery: The Changing Spectrum of Indications.

This report summarizes the state-of-the-art and controversies around patient selection for deep brain stimulation (DBS) for various conditions. Parkinson's disease (PD): several class I studies have shown superiority of DBS over best medical treatment for advanced PD with fluctuations and further inclusion criteria. One class I study suggests that PD patients with early motor complications might gain more quality of life if operated within 3 years after the onset of fluctuations. The subthalamic nucleus (STN) is still the standard target. STN DBS has an impact on impulse control disorders though the exact mechanism is unclear. Tremor: essential tremor (ET) patients found to be eligible for DBS surgery should first be treated with primidone, propranolol, and with a combined therapy preoperatively. Second-line drugs (i.e., topiramate and gabapentin) may be useful. No class I studies exist for DBS treatment of ET. The optimal target of DBS in ET might be the posterior subthalamic area. Dystonia: there is class I evidence for primary generalized and segmental dystonia and for some botulinum-resistant focal dystonias. The impact of age, symptom duration, and DYT-mutation status in primary dystonia on the outcome of DBS surgery clearly demands more studies. DBS has a role in SCGE-mutation positive myoclonus dystonia and tardive dystonia. Finally, neurostimulation in secondary dystonia might be considered in selected patients based on an individual patient's approach.

SP 9. Individualized identification of the motor part of the subthalamic nucleus in Parkinson’s disease

Introduction The subthalamic nucleus (STN), a well known target for deep brain stimulation (DBS) in Parkinson’s disease (PD), is involved in motor, limbic, and cognitive processes ( Temel et al., 2005) . To achieve a successful outcome of DBS surgery the electrode should be placed in its motor part. In current clinical practice, targeting is performed with anatomical 1.5 T or 3T MR images, that display the STN as a homogenous structure. Consistent and patient specific identification of the motor, associative, and limbic zones of the STN with 3T MRI has been demonstrated to be challenging ( Lambert et al., 2012) . Objectives In this study, ultra-high field (7T) MRI was used to map the motor and non-motor areas of the STN in individual patients with PD. Patients and methods The study was approved by the Institutional Review Board at the University of Minnesota and the Local Medical Ethics Committee at Maastricht University Medical Center. Seventeen PD patients (five female, mean age = 62 years), were scanned on a 7T MR scanner (Magnetom 7T Siemens). Three scans were performed: a T1-weighted, a T2-weighted, and a diffusion-weighted scan performed twice with opposite phase encoding directions, along 50 directions with a b-value of 1500 s/mm 2 and 4 b0-volumes (see Table 1 ). Five patients were scanned with slight deviations to this protocol. The motor and non-motor territories of each patient’s STN were identified by tracing their structural connections to the limbic, associative, motor and remaining cortical areas. To this end, the cortex of a reference brain ( Grabner et al., 2006) , was manually divided into these four areas ( Fig. 1 A,B) and registered to each patient’s T1-weighted image. The STNs were manually delineated on each patient’s T2-weighted image and registered to the T1-space as well. Finally probabilistic fiber tracking with each STN as a seed region was performed in T1-space with the FMRIB Software Library (FSL) ( Jenkinson et al., 2012) based on a three-fiber model ( Behrens, 2007) . Results The STNs, with volumes ranging from 75.8 mm 3 to 183.9 mm 3 , were clearly visible on the T2-weighted images( Fig. 1 C) and a clear segregation of the territories was observed ( Fig. 1 D). In all 34 STNs, the superior posterolateral area was connected to the motor cortical area. The volume of the motor area varied from 17.2% to 78.7% of the total STN volume, with an average of 55.3%. In all 34 STNs, the overlapping region in the center was connected to the associative cortical area. Connections to the limbic cortical areas were found in 30 STNs, all from the inferior anteromedial tip of the STN, but with varying sizes. Finally connections to the remaining cortical areas were only found sporadically. Conclusions These results show that ultra-high field MRI can be used to identify the motor and non-motor areas of the STN for each patient individually. The great variability between patients, in volumes of the STN and the motor area also indicate that this mapping should be performed on an individual patient basis. Further studies are currently underway to infer if these maps indeed improve clinical outcome.

Deep brain stimulation as a treatment for neuropathic pain: a longitudinal study addressing neuropsychological outcomes

Abstract Deep brain stimulation (DBS) of the periventricular/periaqueductal gray area and sensory thalamus can reduce pain intensity in patients with neuropathic pain. However, little is known about its impact on quality of life, emotional well-being, and cognition. This study followed up 18 patients who had received DBS for neuropathic pain. Each participant had previously undergone psychometric evaluation of each of the above areas as part of a routine presurgical neuropsychological assessment. Commensurate measures were employed at a follow-up assessment at least 6 months postsurgery. DBS significantly improved mood, anxiety, and aspects of quality of life. Improvements correlated with reduced pain severity. However, the sample continued to show impairments in most areas when compared against normative data published on nonclinical samples. There was little change in general cognitive functioning, aside from deterioration in spatial working memory. However, improvements in pain severity were associated with less improvement (and even deterioration) on measures of executive cognitive functioning. Improvements in emotional well-being also were correlated with changes in cognition. These results suggest that DBS of the periventricular/periaqueductal gray and/or sensory thalamus improves quality of life and emotional well-being in sufferers, although there is some indication of executive dysfunction, particularly among those reporting greatest pain alleviation. Perspective This article examines the neuropsychological outcomes of DBS surgery as a treatment for neuropathic pain. This intervention was found to improve pain severity, emotional well-being, and quality of life, although such benefits may be accompanied by reduced ability on tasks measuring executive functioning.