Wen-han Hu

Selective amygdalohippocampectomy versus anterior temporal lobectomy in the management of mesial temporal lobe epilepsy: a meta-analysis of comparative studies

OBJECT Whether selective amygdalohippocampectomy (SelAH) has similar seizure outcomes and better neuropsychological outcomes compared with anterior temporal lobectomy (ATL) is a matter of debate. The aim of this study was to compare the 2 types of surgery with respect to seizure outcomes and changes in IQ scores. METHODS PubMed, Embase, and the Cochrane Library were searched for relevant studies published between January 1990 and September 2012. Studies comparing SelAH and ATL with respect to seizure and intelligence outcomes were included. Two reviewers assessed the quality of the included studies and independently extracted the data. Odds ratios and standardized mean deviations with 95% confidence intervals were used to compare pooled proportions of freedom from seizures and changes in IQ scores between the SelAH and ATL groups. RESULTS Three prospective and 10 retrospective studies were identified involving 745 and 766 patients who underwent SelAH and ATL, respectively. The meta-analysis demonstrated a statistically significant reduction in the odds of seizure freedom for patients who underwent SelAH compared with those who underwent ATL (OR 0.65 [95% CI 0.51-0.82], p = 0.0005). The differences between the changes in all IQ scores after the 2 types of surgery were not statistically significant, regardless of the side of resection. CONCLUSIONS Selective amygdalohippocampectomy statistically reduced the odds of being seizure free compared with ATL, but the clinical significance of this reduction needs to be further validated by well-designed randomized trials. Selective amygdalohippocampectomy did not have better outcomes than ATL with respect to intelligence.

Risk factors for post-stroke seizures: a systematic review and meta-analysis.

PURPOSE To perform a systematic review and meta-analysis to identify risk factors associated with early seizure (ES) or late seizure (LS) onset in adults following stroke. DATA SOURCES Electronic databases (MEDLINE and EMBASE), archives of stroke or epilepsy patients, and bibliographies of relevant articles, which were written in English. STUDY SELECTION We included studies published since 1990 that reported the stroke and seizure outcomes of adult patients during follow-up. We independently performed title, abstract and full-text screening and resolved disagreements through discussion. DATA EXTRACTION Two authors performed the data extraction. We recorded all possible risk factors predictive of seizure onset. DATA SYNTHESIS We used odds ratios (ORs) or the mean difference (MD) to compare the pooled rates of seizure onset between the exposed group and the non-exposed group. All meta-analyses were performed with Review Manager Software. RESULTS Intracerebral hemorrhage (OR=1.88, 95% CI=1.43-2.47), cerebral infarction with hemorrhagic transformation (OR=3.28, 95% CI=2.09-5.16), stroke severity (OR=3.10, 95% CI=2.00-4.81, p<0.01, I(2)=0%; MD=3.98, 95% CI=1.06-6.90, p<0.01), and alcoholism (OR=1.70, 95% CI=1.23-2.34, p<0.01) were associated with a significantly greater probability of ES occurrence. There were significant effects of cortical involvement (OR=2.50, 95% CI=1.93-3.23) and stroke severity (MD=5.72, 95% CI=4.23-7.22, p<0.01, I(2)=0) on LS onset. However, there was no significant difference in the probability of single LS episode between patients with intracerebral hemorrhage and infarction stroke (OR=1.20, 95% CI=0.92-1.55). CONCLUSIONS Evidence suggests that cortical involvement, stroke subtypes and stroke severity are significant predictors of seizure onset following stroke. However, we did not find a significant difference in the rate of onset of single LS episodes between patients with intracerebral hemorrhage and cerebral infarction.

Predictors of seizure freedom after surgical management of tuberous sclerosis complex: a systematic review and meta-analysis.

PURPOSE To evaluate the rate of seizure freedom in surgical management of tuberous sclerosis complex (TSC) and to identify factors associated with postoperative seizure outcome. METHODS A comprehensive literature search identified articles published since 1990 that described seizure outcomes in patients with TSC who underwent resective surgery. Two reviewers assessed article eligibility and independently extracted the data. Eleven potential prognostic variables were identified and dichotomized for analyses. Random or fixed effects meta-analyses were used depending on the presence or absence of heterogeneity. RESULTS Among 229 patients in 13 studies, the pooled rate of postoperative seizure freedom was 59%. Seizure onset later than 1 year of age, unilateral focality in interictal or ictal electroencephalography, and lobectomy were significantly associated with a higher rate of seizure freedom. CONCLUSIONS Our findings indicate that surgery is an effective treatment modality for TSC patients. The meta-analyses provided useful evidence-based information for identifying TSC candidates for epilepsy surgery and planning surgical strategy.

Bilateral subthalamic nucleus stimulation in the treatment of neurodegeneration with brain iron accumulation type 1.

Background: Neurodegeneration with brain iron accumulation type 1 (NBIA1), previously called Hallervorden-Spatz disease, is a rare neurodegenerative condition with abnormal brain iron accumulation. There have been some reports of deep brain stimulation (DBS) in the treatment of NBIA1. However, the target was usually the globus pallidus internus or thalamus. Objectives/Methods: We present a case of NBIA1 in a 16-year-old male who was treated with bilateral subthalamic nucleus (STN)-DBS and explored its efficacy in the treatment of NBIA1. The patient presented with severe generalized dystonia and marked dysarthria and had previously had unsuccessful ablation surgery. MRI confirmed the diagnosis of NBIA1. Results: He had significant improvement postoperatively, and the benefit of surgery was maintained for 3 years during follow-up. Burke-Fahn-Marsden Dystonia Rating Scale score was 114/120 preoperatively, and dropped to 60/120 at 14 days, 35/120 at 1 month, 28/120 at 3 months, 14/120 at 1 year and 18/120 at 3 years postoperatively. Conclusions: Our results suggest that bilateral STN-DBS might be considered as an effective treatment for selective NBIA1 patients.

Behavioral Effects of Deep Brain Stimulation of the Anterior Nucleus of Thalamus, Entorhinal Cortex and Fornix in a Rat Model of Alzheimer's Disease

Background: Recent clinical and preclinical studies have suggested that deep brain stimulation (DBS) can be used as a tool to enhance cognitive functions. The aim of the present study was to investigate the impact of DBS at three separate targets in the Papez circuit, including the anterior nucleus of thalamus (ANT), the entorhinal cortex (EC), and the fornix (FX), on cognitive behaviors in an Alzheimers disease (AD) rat model. Methods: Forty-eight rats were subjected to an intrahippocampal injection of amyloid peptides 1-42 to induce an AD model. Rats were divided into six groups: DBS and sham DBS groups of ANT, EC, and FX. Spatial learning and memory were assessed by the Morris water maze (MWM). Recognition memory was investigated by the novel object recognition memory test (NORM). Locomotor and anxiety-related behaviors were detected by the open field test (OF). By using two-way analysis of variance (ANOVA), behavior differences between the six groups were analyzed. Results: In the MWM, the ANT, EC, and FX DBS groups performed differently in terms of the time spent in the platform zone (F (2,23) = 6.04, P < 0.01), the frequency of platform crossing (F (2,23) = 11.53, P < 0.001), and the percent time spent within the platform quadrant (F (2,23) = 6.29, P < 0.01). In the NORM, the EC and FX DBS groups spent more time with the novel object, although the ANT DBS group did not (F (2,23) = 10.03, P < 0.001). In the OF, all of the groups showed a similar total distance moved (F (1,42) = 1.14, P = 0.29) and relative time spent in the center (F (2,42) = 0.56, P = 0.58). Conclusions: Our results demonstrated that DBS of the EC and FX facilitated hippocampus-dependent spatial memory more prominently than ANT DBS. In addition, hippocampus-independent recognition memory was enhanced by EC and FX DBS. None of the targets showed side-effects of anxiety or locomotor behaviors.

Atypical trigeminal neuralgia: A consequence of central sensitization?

Trigeminal neuralgia (TN) is characterized by sudden, recurrent, usually unilateral, severe brief stabbing pains in the distribution of trigeminal nerve. Although it is widely accepted that blood vessel or tumor compression contributes to paroxysms of TN, the pathogenesis of persistent background pain in atypical TN patient is unclear. Central sensitization is pain hypersensitivity caused by central neural plasticity. It is responsible for many temporal and symptomatic features of acute and chronic pain. We hypothesize that central sensitization might account for some symptoms of atypical TN. Based on this hypothesis, we postulate that early medical intervention predicts good outcomes in TN and medicines which are effective on central sensitization may be potential agents for the treatment of atypical TN.

Prognostic factors for seizure outcome in patients with MRI-negative temporal lobe epilepsy: A meta-analysis and systematic review

PURPOSE To perform a systematic review and meta-analysis to identify predictors of postoperative seizure freedom in patients with magnetic resonance imaging (MRI)-negative temporal lobe epilepsy. METHOD Publications were screened from electronic databases (MEDLINE, EMBASE), epilepsy archives, and bibliographies of relevant articles that were written in English. We recorded all possible risk factors that might predict seizure outcome after surgery. We calculated odds ratio (OR) with corresponding 95% confidence intervals (95% CI) of predictors for postoperative seizure freedom. Heterogeneity was assessed with I(2). All meta-analyses were performed using Review Manager. RESULTS Epilepsy duration (OR=2.57, 95% CI=1.21-5.47, p<0.05, I(2)=1%) and ictal or interictal electroencephalographic anomalies precisely localized in the ipsilateral temporal lobe (OR=3.89, 95% CI=1.66-9.08, p<0.01, I(2)=0 and OR=3.38, 95% CI=1.57-7.25, p<0.05, I(2)=0, respectively) were significantly associated with a higher rate of seizure freedom after surgery. However, the positron emission tomography (PET) results were not predictive of postoperative seizure freedom (OR=2.11, 95% CI=0.95-4.65, p=0.06, I(2)=0). No significant difference in seizure freedom was observed between the positive and negative pathology groups (OR=1.36, 95% CI=0.70-2.63, p=0.36, I(2)=0). CONCLUSIONS A shorter epilepsy duration and scalp electroencephalogram (EEG) signals localized precisely in the temporal lobe predicted a better seizure outcome in patients with MRI-negative temporal lobe epilepsy.

Deep Brain Stimulation for Craniocervical Dystonia (Meige Syndrome): A Report of Four Patients and a Literature-Based Analysis of Its Treatment Effects.

The aim of this study was to report on four patients with craniocervical dystonia (CCD) treated with deep brain stimulation (DBS). In addition, we investigated the treatment efficacy and surgical outcome predictors by the review and analysis of previously published studies.

Responsive neurostimulation for the treatment of medically intractable epilepsy

With an annual incidence of 50/100,000 people, nearly 1% of the population suffers from epilepsy. Treatment with antiepileptic medication fails to achieve seizure remission in 20-30% of patients. One treatment option for refractory epilepsy patients who would not otherwise be surgical candidates is electrical stimulation of the brain, which is a rapidly evolving and reversible adjunctive therapy. Therapeutic stimulation can involve direct stimulation of the brain nuclei or indirect stimulation of peripheral nerves. There are three stimulation modalities that have class I evidence supporting their uses: vagus nerve stimulation (VNS), stimulation of the anterior nuclei of the thalamus (ANT), and, the most recently developed, responsive neurostimulation (RNS). While the other treatment modalities outlined deliver stimulation regardless of neuronal activity, the RNS administers stimulation only if triggered by seizure activity. The lower doses of stimulation provided by such responsive devices can not only reduce power consumption, but also prevent adverse reactions caused by continuous stimulation, which include the possibility of habituation to long-term stimulation. RNS, as an investigational treatment for medically refractory epilepsy, is currently under review by the FDA. Eventually systems may be developed to enable activation by neurochemical triggers or to wirelessly transmit any information gathered. We review the mechanisms, the current status, the target options, and the prospects of RNS for the treatment of medically intractable epilepsy.

High-frequency electrical stimulation in the nucleus accumbens of morphine-treated rats suppresses neuronal firing in reward-related brain regions

Summary Background Previous studies have reported that high-frequency stimulation (HFS) in the nucleus accumbens (NAc) is a potential treatment modality for drug craving and relapse. We aimed to explore the electrophysiological changes in reward-related brain regions during NAc stimulation and reveal the effects of stimulation frequency and target changes on NAc neuronal activities. Material/Methods Twenty-eight rats were randomized into saline (n=8) and morphine (n=20) groups. The morphine group was further divided into core (n=10, only the core of the NAc was stimulated) and shell (n=10, only the shell of the NAc was stimulated) subgroups. Conditioned place preference (CPP) behavior of the rats was evaluated to confirm morphine preference after morphine injection and CPP training for 10 days. We recorded NAc neuronal responses to NAc core stimulation at different frequencies, as well as changes in VP and VTA neuronal firing during NAc core stimulation, and changes in NAc neuronal firing during NAc shell stimulation. Results The results indicate that high frequency stimulation was more effective in suppressing NAc neuronal activities than low frequency stimulation and that core stimulation was more effective than shell stimulation. Most VP neurons were inhibited by NAc core stimulation, while VTA neurons were not. Conclusions The results suggest that electrical stimulation in the NAc can suppress neuronal firing in reward-related brain regions. The stimulation might be frequency- dependent in suppressing neuronal firing. The core and shell of the NAc play different roles in suppressing NAc neuronal firing as 2 stimulating targets.