Summary:Purpose: The anterior nucleus of the thalamus (ANT) modulates temporal lobe and hypothalamic activities, and relays information to the cingulate gyrus and entorhinal cortex. Deep brain stimulation (DBS) of the ANT has been reported to decrease seizure activity in a limited number of human subjects. However, long-term effect of chronic ANT stimulation on such patients remains unknown. We report long-term follow-up results in four patients receiving ANT stimulation for intractable epilepsy.Methods: Four patients underwent stereotactic implantation of quadripolar stimulating electrodes in the bilateral ANT, guided by single-unit microelectrode recording. Electrode location was confirmed by postoperative magnetic resonance imaging (MRI). The stimulator was activated 2-4 weeks following electrode insertion; initial stimulation parameters were 4-5 V, 90-110 Hz, and 60-90 µs. Seizure frequency was monitored and compared with preimplantation baseline frequency. Intelligence quotient (IQ) test and auditory P300 response were performed before and after implantation of electrodes.Results: Four patients (one man with generalized seizures, and three women with partial seizures and secondary generalization) aged 18-45 years old were studied with mean followup period of 43.8 months. The four patients demonstrated a sustained effect of 49% (range, 35-76%) seizure reduction to ANT stimulation. Simple insertion of DBS electrodes (Sham period, no stimulation) produced a mean reduction in seizures of 67% (range, 44-94%). One patient was seizure-free for 15 months with anticonvulsant medications. One patient had a small frontal hemorrhage and a second patient had extension erosion over scalp; no resultant major or permanent neurological deficit was observed. Preoperative IQ index and auditory P300 were not significantly different with those after electrodes implantation.Conclusions: Implantation of electrodes in the ANT and subsequent stimulation is associated with a significant reduction in seizure frequency. However, our study could not differentiate whether the implantation itself, the subsequent stimulation or postimplantation drug manipulation had the greatest impact. These experimental results prompt further controlled study in a large patient population.

New-onset vertebral compression fractures occurred repeatedly within a few years after vertebroplasty. New-onset adjacent-level fractures occurred sooner and were more predominate than nonadjacent level fractures. The results of this study suggest that older patient age, lower baseline BMD, and more pre-existing vertebral fractures were found to be risk factors for multiple vertebral compression fractures.

ObjectiveElectrical stimulation of the hippocampus offers the possibility to treat patients with mesial temporal lobe epilepsy (MTLE) who are not surgical candidates. We report long‐term follow‐up results in five patients receiving low or high frequency hippocampal stimulation for drug‐resistant MTLE.Materials and MethodsThe patients underwent stereotactic implantation of quadripolar stimulating electrodes in the hippocampus. Two of the patients received unilateral electrode implantation, while the other three received bilateral implantation. Stimulation of the hippocampal electrodes was turned ON immediately after the implantation of an implantable pulse generator, with initial stimulation parameters: 1 V, 90–150 μs, 5 or 145 Hz. The frequency of seizures was monitored and compared with preimplantation baseline data.ResultsTwo men and three women, aged 27–61 years were studied, with a mean follow‐up period of 38.4 months (range, 30–42 months). The baseline seizure frequency was 2.0–15.3/month. The five patients had an average 45% (range 22–72%) reduction in the frequency of seizures after hippocampal stimulation over the study period. Low frequency hippocampal stimulation decreased the frequency of seizures in two patients (by 54% and 72%, respectively). No implantation‐ or stimulation‐related side effects were reported.ConclusionsElectrical stimulation of the hippocampus is a minimally invasive and reversible method that can improve seizure outcomes in patients with drug‐resistant MTLE. The optimal frequency of stimulation varied from patient to patient and therefore required individual setting. These experimental results warrant further controlled studies with a large patient population to evaluate the long‐term effect of hippocampal stimulation with different stimulation parameters.

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Freezing of gait (FOG) is a disabling clinical phenomenon often found in patients with advanced Parkinson's disease (PD). FOG impairs motor function, causes falls and leads to loss of independence. Whereas dual tasking that distracts patients' attention precipitates FOG, auditory or visual cues ameliorate this phenomenon. The pathophysiology of FOG remains unclear. Previous studies suggest that the basal ganglia are involved in the generation of FOG. Investigation of the modulation of neuronal activities within basal ganglia structures during walking is warranted. To this end, we recorded local field potentials (LFP) from the subthalamic nucleus (STN) while PD patients performed single-task gait (ST) or walked while dual-tasking (DT). An index of FOG (iFOG) derived from trunk accelerometry was used as an objective measure to differentiate FOG-vulnerable gait from normal gait. Two spectral activities recorded from the STN region were associated with vulnerability to freezing. Greater LFP power in the low beta (15–21 Hz) and theta (5–8 Hz) bands were noted during periods of vulnerable gait in both ST and DT states. Whereas the elevation of low beta activities was distributed across STN, the increase in theta activity was focal and found in ventral STN and/or substantia nigra (SNr) in ST. The results demonstrate that low beta and theta band oscillations within the STN area occur during gait susceptible to freezing in PD. They also add to the evidence that narrow band ~18 Hz activity may be linked to FOG.

Introduction: Chronic hydrocephalus is a common complication that can occur after aneurysmal subarachnoid haemorrhage (SAH). The purpose of this study was to investigate clinical risk factors that could predict the occurrence of shunt-dependent chronic hydrocephalus after aneurysmal SAH. Methods: Eighty-eight consecutive patients who underwent either surgery or transarterial endovascular embolization as a treatment for cerebral aneurysm within 72 h -after experiencing SAH from March 2005 to July 2006 were studied retrospectively to assess the risk factors that might predict shunt-dependent chronic hydrocephalus. Clinical and demographic factors were examined, including age, sex, initial admission mean arterial blood pressure (MABP), blood sugar level at admission, fever frequency, initial external ventricular drainage (EVD), Fisher grade, Hunt and Hess grade, intraventricular haemorrhage (IVH) and treatment methods to define predictors of shunt-dependent hydrocephalus. The length of hospital stay and modified Rankin scale recorded 6 months after SAH were also evaluated; these parameters were compared between the shunt-dependent and non-shunt-dependent groups. Results: Of the 88 patients, 22 (25%) underwent shunt placement to treat their chronic hydrocephalus. The average length of hospital stay was 33.9 days for the shunt-treated group and 14 days for the non-shunt-treated group. The non-shunt-treated group scored an average of 1.05 on the modified Rankin scale compared with 2.77 for the shunt-treated group. A univariate analysis revealed that several admission variables were associated with long-term shunt-dependent hydrocephalus: (1) increased age (p = 0.023); (2) initial admission MABP (p = 0.027); (3) a high Fisher grade (p = 0.031); (4) a poor admission Hunt and Hess grade (p = 0.030); (5) the presence of IVH (p = 0.029), and (6) initial EVD (p < 0.0001). The factor most commonly associated with shunt-dependent hydrocephalus over the course of hospital days was fever frequency (p < 0.0001). Conclusions: Chronic hydrocephalus after aneurysmal SAH has a multifactorial aetiology. Understanding the risk factors that predict the occurrence of chronic hydrocephalus may help neurosurgeons to expedite permanent cerebrospinal fluid diversion, which could decrease both the cost and length of hospital stay and prevent further complications.

Object The management of subdural empyema (SDE) has been debated in the literature for decades. Craniotomy and bur hole drainage have been shown to achieve a favorable outcome. However, there is a lack of comparative data for these modes of management of SDE subsequent to meningitis in infants. Methods The authors conducted a retrospective review of 33 infants identified with SDE due to meningitis at the Department of Neurosurgery, Chang Gung Memorial Hospital between 2000 and 2006. Preoperative clinical presentation, duration of symptoms, radiological investigations, CSF data, and postoperative outcome were analyzed and compared between these 2 surgical groups. Results At diagnosis, there were no differences between the groups in age, weight, degree of consciousness, CSF analysis, or duration of fever. The outcome data showed no difference in the number of days until afebrile, number of days of postsurgical antibiotic treatment, neurological outcome, recurrence rate, or complication rate. There was only 1 death in the series. Conclusions Subdural empyema due to meningitis in infants is unique with respect to the pathophysiology, presentation, and treatment of SDE. Early detection and removal of SDE provide a favorable outcome in both surgical intervention groups. Bur hole drainage is less invasive, and it is possible to expect a clinical outcome as good as with craniotomy in postmeningitic SDE.

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