Jeffrey A. Brown

Motor cortex stimulation for the enhancement of recovery from stroke: a prospective, multicenter safety study.

OBJECTIVE: Functional magnetic resonance imaging and transcranial magnetic stimulation studies suggest that human cortex shows evidence of neuroplasticity. Preclinical studies in rats and monkeys suggest that motor cortical stimulation can enhance plasticity and improve recovery after stroke. This study assesses the safety and preliminary efficacy of targeted subthreshold epidural cortical stimulation delivered concurrently with intensive rehabilitation therapy while using an investigational device in patients with chronic hemiparetic stroke. METHODS: This is a prospective, multicenter, and nonblinded trial randomizing patients to rehabilitation with or without cortical stimulation. Patients aged 20 to 75 years who had had an ischemic stroke at least 4 months previously causing persistent moderate weakness of the arm were included. Functional magnetic resonance imaging localized hand motor function before surgery to place an epidural cortical electrode. Both groups then underwent rehabilitation for 3 weeks after which the electrode was removed. Outcome measures were obtained at baseline, during therapy, and at 1, 4, 8, and 12 weeks postprocedure. RESULTS: Ten patients were randomized; six patients to surgery, four to the control group. No patient deaths, neurological deterioration, or seizures occurred. There were two infections from nonprotocol-related causes. Of the eight patients completing the treatment, the stimulation plus rehabilitation group improved significantly better than controls in the Upper Extremity Fugl-Meyer (P = 0.003 overall) and the hand function score of the Stroke Impact Scale (P = 0.001 overall). CONCLUSION: The technique of cortical stimulation to enhance stroke recovery is well tolerated and safe.

Motor cortex stimulation for central and neuropathic pain: current status.

The idea that central pain syndromes can be treated by manipulation of the motor cortex derives from the landmark observations of Penfield (Lende et al., 1971). While reoperating on patients on whom he had previously resected a portion of the post central gyrus for epilepsy and whose seizures recurred, Penfield observed that stimulation of the corresponding primary motor cortex elicited sensory responses (Lende et al., 1971). Sweet and White achieved only 13% pain relief with post central gyrectomy and recommended abandoning the operation (White and Sweet, 1955). Based on their observations of Penfield’s work and on the failure of post central gyrectomy alone, (Lende et al., 1971) treated three patients with facial neuropathic pain by resecting both the post central and corresponding pre central gyri, providing them long-term pain relief. No other reports of this aggressive technique have been published. The use of central electrical stimulation to treat various pain problems is beyond the scope of this review. Most of the early work (deep brain stimulation, DBS) involved stereotaxic placement of electrodes into well-defined targets using stereotaxic techniques, including the sensory thalamus and midbrain periaqueductal or periventricular gray. Because there was insufficient data to support efficacy and safety of these procedures, DBS for pain was largely abandoned in the United States.

Motor cortex stimulation for central and neuropathic facial pain: a prospective study of 10 patients and observations of enhanced sensory and motor function during stimulation.

OBJECTIVE:For more than a decade, motor cortex stimulation has been used to treat difficult central and peripheral neuropathic pain syndromes. This prospective study uses the McGill Pain Questionnaire, a visual analog scale (VAS) score, and an inventory of drug consumption to review the results of treating patients with trigeminal neuropathic pain via motor cortex stimulation. METHODS:Ten patients underwent motor cortex stimulation between 1999 and 2002. Implantation was performed via intraoperative neuronavigation and cortical mapping for stimulation site targeting. Nine patients had trigeminal neuropathic pain from postherpetic neuralgia, surgical injury, or unknown cause, and one patient had pain of central origin. Patients were evaluated with multimodality scales before, immediately after, and at designated intervals after surgery. Eight patients underwent permanent implantation after a trial evaluation. In two patients, the stimulating electrodes were removed after an unsuccessful trial. One of these patients had a lateral medullary infarct leading to central pain, and in another patient, there was no explanation for the pain. RESULTS:The average duration of pain before surgery was 6 years. Postoperatively, there was an 88% rate of immediate pain relief (>50% on VAS) and a 75% rate of pain relief at mean follow-up of 10 months (range, 3–24 mo). Mean preoperative McGill Pain Questionnaire total pain rating index was 57 (higher than that observed in causalgia) for patients who did not undergo implantation and 53 for those who underwent implantation. Mean McGill Pain Questionnaire pain rating index at mean follow-up of 10 months was 24 (55% decrease). Mean VAS preoperatively was 9 in patients with stimulator implants and 8 in those whose stimulator was removed after the trial. Immediate postoperative mean VAS score was 1. This score stabilized 3 months after surgery. Patients with implanted stimulators reduced their pain medication dose by a mean of more than 50%. Three patients with facial weakness and sensory loss regained both strength and discriminative sensation during stimulation. In another patient, dysarthria improved. In a review of the literature, 29 (76%) of 38 patients with neuropathic facial pain treated with motor cortex stimulation achieved greater than 50% pain relief. CONCLUSION:These results provide further support for the use of motor cortex stimulation in facial neuropathic pain and document pain improvement as measured by multidimensional scales. Observations of motor and sensory improvements during stimulation suggest that stimulation alters cortical plasticity and inhibits thalamic hyperactivity.

Motor cortex stimulation for enhancement of recovery after stroke: Case report

Abstract We present a case report of a 65-year-old patient who had a subcortical infarct and a right spastic hemiparesis that occurred 19 months before being treated with an investigational therapy consisting of low frequency subthreshold epidural motor cortex electrical stimulation delivered during structured occupational therapy repeated daily for three weeks. Before treatment the patients affected arm rested in a flexion posture and he was unable to flex or extend the fingers. After three weeks of treatment, the resting tone of his arm had improved and he was able to grasp a pen and write letters. The Fugl-Meyer motor scale score improved from 36 to 46 and this improvement was sustained for four weeks after the conclusion of rehabilitation therapy. This is the first patient to be entered into a randomized clinical feasibility and safety study assessing functional improvement in stroke patients treated with epidural cortical stimulation concurrent with occupational therapy (an investigational therapy).

Psychopharmacologic Treatment of Acquired Attention Disorders in Children with Brain Injury

This investigation examined the efficacy of psychostimulant therapy in alleviating neurobehavioral dysfunction attendant to pediatric brain injury. The most commonly reported neurobehavioral sequelae associated with head injury in the pediatric population involve deficits along the attentional matrix. This is also the most common objectively documented neurobehavioral finding among children as well as adults. There are several investigations in the adult literature which have employed the use of psychostimulants in treating both psychiatric and neuropsychological residua associated with head injury. Overall, the results of these studies are equivocal, but suggest a beneficial impact on general functioning. The present prospective investigation utilized a double-blind, placebo-controlled, cross-over experimental design to examine the efficacy of methylphenidate in treating children with acquired attentional disorders secondary to brain injury. A cohort of 14 children with varying degrees of head injury were recruited for participation. As expected, differences between drug and placebo conditions uniformly achieved statistical significance. Additionally, there were no differences in performance between baseline and placebo conditions on neurobehavioral tasks of attention and concentration. Current findings suggest that methylphenidate (and probably other psychostimulants such as Cylert, Adderal, Wellbutrin and dextroamphetamine sulfate) is an extremely effective agent in treating attentional disorders secondary to brain injury in children.

Trigeminal depressor response during percutaneous microcompression of the trigeminal ganglion for trigeminal neuralgia

Percutaneous microcompression of the trigeminal ganglion for trigeminal neuralgia was performed 23 times on 21 patients. Significant abrupt drops in heart rate and blood pressure (P less than 0.0002) occurred when the needle entered the foramen ovale or upon balloon advancement or inflation. In 16 of 23 (70%) procedures, the heart rate fell abruptly to 60 or less, by a mean of 38%. Mean arterial blood pressure decreased transiently by 31% during 12 of 23 (55%) procedures. Our findings of transient bradycardia and hypotension upon mechanical stimulation or compression of the mandibular nerve or trigeminal ganglion show for the first time the presence of a trigeminal depressor response in humans. We recommend that heart rate and arterial blood pressure be monitored continuously during percutaneous microcompression of the trigeminal ganglion. Intravenous atropine should be available for immediate use, and an external pacemaker should be fitted preoperatively.

Intracranial infection after missile injuries to the brain: report of 30 cases from the Lebanese conflict.

This study reviews the features of 30 intracranial infections complicating 600 penetrating head injuries from missiles in patients treated at the American University of Beirut Medical Center between 1981 and 1988. The follow-up period ranged from 1 month to 7 years (mean, 2.5 years). Sixteen patients had a brain abscess, 9 had cerebritis, 2 had an infected intracerebral hematoma, and 5 had meningitis. Infection developed 4 days to 7 years after the initial debridement. The infecting organisms were Gram positive in 11 patients (36%), Gram negative in 12 (40%), and a combination of Gram positive and Gram negative in 2 (7%). Twenty-four patients (80%) had wound dehiscence or cerebrospinal fluid leakage at the time the infection appeared. There was a 76% correlation between the organisms cultured from the dehiscent scalp wound and the brain. Twenty-three patients had intracranial retention of bone. Infection developed in 16 of the 30 patients (70%) around bone fragments, in 4 around a metallic fragment, in 2 around absorbable gelatin sponge, and in 3 along the missile tract; 2 had an infected intracerebral hematoma, and 3 had meningitis. At least one of the following risk factors was present in each patient: extensive brain injury, coma, trajectory through an air sinus, cerebrospinal fluid fistula, inadequate initial debridement, or incomplete dural closure. The incidence of intracranial infection in patients with postoperative retention of bone was 4% in the absence of scalp wound dehiscence, compared with 84.6% when wound dehiscence was present. Ten patients (43%) still retained a bone fragment measuring less than 1 cm after excision of a brain abscess or treatment of cerebritis or meningitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Missile Injuries to the Brain Treated by Simple Wound Closure: Results of a Protocol during the Lebanese Conflict

This is a prospective study of the treatment of penetrating missile injuries to the brain without intracranial surgery carried out at the American University of Beirut Medical Center between 1981 and 1988. Of 600 patients treated for missile injuries to the head, 32 satisfied the study criteria. There were 27 shrapnel and 5 bullet injuries. The mean patient age was 23 years (range, 3-51 years). Twenty patients had intracranial indriven bone fragments. Six patients had exposed brain tissue. The mean follow-up was 3.5 years (range, 1-7.5 years). The superficial entry wound was debrided and closed without drainage in the Emergency Room within a mean of 3 hours (range, 0.5-6 hours), and the patient received methicillin for 14 days. All patients survived and had no or improved neurological deficits. No leakage of the cerebrospinal fluid, infection, or seizures occurred in 31 patients. One patient with indriven bone fragments had leakage of the cerebrospinal fluid and developed seizures and a brain abscess 20 days after the injury. The management of penetrating missile injuries to the brain without intracranial surgery in a select patient population is a reasonable option. This treatment becomes important for a surgeon facing large numbers of casualties, or when operative personnel or resources are limited or unavailable.

Pyriformis syndrome in a 10-year-old boy as a complication of operation with the patient in the sitting position.

We present a case of sciatic neuropathy due to the pyriformis syndrome after operation in the sitting position. Neither sciatic nerve injury nor the pyriformis syndrome has been reported after operation in the sitting position, although a low incidence of common peroneal nerve injury has been reported as a complication of operation on patients who are in the sitting position. The clinical findings of sciatic neuropathy, external rotation of the ipsilateral foot in the position of comfort, and a therapeutic response to local anesthetic injection into the pyriformis muscle are diagnostic of the syndrome. Nerve conduction studies should be performed to aid in the differentiation between a common peroneal and sciatic neuropathy. The syndrome may occur because of extreme flexion of the hips and prolonged pressure while in the sitting position, leading to pyriformis muscle trauma, resultant spasm, and sciatic compression. The prognosis is for complete recovery after symptomatic treatment with nonsteroidal antiinflammatory medication and physical therapy.

Use of Functional MRI to Guide Decisions in a Clinical Stroke Trial

Background and Purpose— An investigational trial examined safety and efficacy of targeted subthreshold cortical stimulation in patients with chronic stroke. The anatomical location for the target, hand motor area, varies across subjects, and so was localized with functional MRI (fMRI). This report describes the experience of incorporating standardized fMRI into a multisite stroke trial. Methods— At 3 enrollment centers, patients moved (0.25 Hz) the affected hand during fMRI. Hand motor function was localized at a fourth center guiding intervention for those randomized to stimulation. Results— The fMRI results were available within 24 hours. Across 12 patients, activation site variability was substantial (12, 23, and 11 mm in x, y, and z directions), exceeding stimulating electrode dimensions. Conclusion— Use of fMRI to guide decision-making in a clinical stroke trial is feasible.