Alternating verbal fluency performance following bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease.

BACKGROUND AND PURPOSE: Despite common occurrences of verbal fluency declines following bilateral subthalamic nucleus deep brain stimulation (STN-DBS) for the treatment of Parkinson's disease (PD), alternating fluency measures using cued and uncued paradigms have not been evaluated. METHODS: Twenty-three STN-DBS patients were compared with 20 non-surgical PD patients on a comprehensive neuropsychological assessment, including cued and uncued intradimensional (phonemic/phonemic and semantic/semantic) and extradimensional (phonemic/semantic) alternating fluency measures at baseline and 6-month follow-up. RESULTS: STN-DBS patients demonstrated a greater decline on the cued phonemic/phonemic fluency and the uncued phonemic/semantic fluency tasks compared to the PD patients. For STN-DBS patients, verbal learning and information processing speed accounted for a significant proportion of the variance in declines in alternating phonemic/phonemic and phonemic/semantic fluency scores, respectively, whilst only naming was related to uncued phonemic/semantic performance for the PD patients. Both groups were aided by cueing for the extradimensional task at baseline and follow-up, and the PD patients were also aided by cueing for the phonemic/phonemic task on follow-up. CONCLUSIONS: These findings suggest that changes in alternating fluency are not related to disease progression alone as STN-DBS patients demonstrated greater declines over time than the PD patients, and this change was related to declines in information processing speed.

Vagus nerve stimulation (VNS) for treatment-resistant depressions: a multicenter study.

BACKGROUND: Vagus Nerve Stimulation (VNS) delivered by the NeuroCybernetic Prosthesis (NCP) System was examined for its potential antidepressant effects. METHODS: Adult outpatients (n = 30) with nonpsychotic, treatment-resistant major depressive (n = 21) or bipolar I (n = 4) or II (n = 5; depressed phase) disorders who had failed at least two robust medication trials in the current major depressive episode (MDE) while on stable medication regimens completed a baseline period followed by NCP System implantation. A 2-week, single-blind recovery period (no stimulation) was followed by 10 weeks of VNS. RESULTS: In the current MDE (median length = 4.7 years), patients had not adequately responded to two (n = 9), three (n = 2), four (n = 6), or five or more (n = 13) robust antidepressant medication trials or electroconvulsive therapy (n = 17). Baseline 28-item Hamilton Depression Rating Scale (HDRS(28)) scores averaged 38.0. Response rates (> or =50% reduction in baseline scores) were 40% for both the HDRS(28) and the Clinical Global Impressions-Improvement index (score of 1 or 2) and 50% for the Montgomery-Asberg Depression Rating Scale. Symptomatic responses (accompanied by substantial functional improvement) have been largely sustained during long-term follow-up to date. CONCLUSIONS: These open trial results suggest that VNS has antidepressant effects in treatment-resistant depressions.

Cervical diastematomyelia. Report of a case and review of a rare congenital anomaly.

Cervical diastematomyelia is a rare congenital abnormality. To our knowledge, only 18 cases have been reported. The present case was highly unusual in that it occurred in an adult. Other clinical features in the present case included symptoms that began after trauma and the presence of other associated congenital anomalies. The diastematomyelia was identified with computed tomographic metrizamide myelography and magnetic resonance imaging. The patient's neurologic deficits improved with surgery.

Thalamic deep brain stimulation: comparison between unilateral and bilateral placement.

BACKGROUND: Unilateral thalamic deep brain stimulation (DBS) is accepted as an effective treatment for essential tremor (ET) and the tremor of Parkinson disease (PD). There are, however, relatively little data concerning bilateral thalamic DBS and no thorough comparisons between the 2 methods. METHODS: To assess the relative benefit of a staged second contralateral DBS placement in patients with PD and ET, we compared preoperative baseline assessments with those at 3 months after the initial implantation, and again at 3 months after the second contralateral implantation. The assessments included the Unified Parkinson's Disease Rating Scale for patients with PD (n = 8) and a modified Unified Tremor Rating Assessment for patients with ET (n = 13). The design included open and blinded (unknown activation status) assessments. RESULTS: Overall, after the second implantation, all specific measures assessing tremor contralateral to that side improved in patients with PD and ET, generally without sacrificing those contralateral to the first side implantation. Midline tremors (face and head) improved only after the second side implantation. In patients with ET, functional and subjective scores tended to further improve after the second placement; however, patients with PD had less subjective improvement. Hand tremor scores in patients with ET randomized to "on" stimulation improved from 6.7 +/- 0.9 to 1.3 +/- 1.2 (P<.005). The scores of patients with PD randomized to on stimulation improved from 9.3 +/- 1.0 to 1.0 +/- 0.5. (Data are given as mean +/- SD.) Tremor scores did not change from baseline in those patients randomized to "off" stimulation in either group. Adverse events related to stimulation increased after the second implantation in both groups. CONCLUSIONS: Bilateral thalamic DBS is more effective than unilateral DBS at controlling bilateral appendicular and midline tremors of ET and PD. Despite this, overall functional disability only improved in patients with ET, possibly secondary to more problematic adverse events in patients with PD, especially balance problems. Bilateral DBS should be considered when unilateral DBS does not offer satisfactory benefit, especially in patients with ET.

Unilateral thalamic deep brain stimulation for refractory essential tremor and Parkinson's disease tremor.

OBJECTIVE: To determine the efficacy and tolerability of unilateral thalamic deep brain stimulation (DBS) for patients with medically refractory essential tremor (ET) and the tremor associated with Parkinson's disease (PD). BACKGROUND: The tremor of ET and PD may produce functional disability despite optimal medical therapy. Several reports have demonstrated efficacy of thalamic DBS in this scenario. METHODS: Preoperative and 3-month postoperative tremor ratings were compared in 33 patients (14 ET and 19 PD) with severe tremor. Evaluations included Unified Parkinson's Disease Rating Scale (UPDRS) scores for PD patients and a modified Unified Tremor Rating Scale in ET patients. Open-label and blinded data (unknown activation status) were obtained. RESULTS: ET patients demonstrated an 83% reduction (p < 0.0001) in observed contralateral arm tremor. All measures of tremor including writing samples, pouring tests, subjective functional surveys, and disability scores improved significantly. PD patients demonstrated an 82% reduction (p < 0.0001) in contralateral tremor and significant improvement in disability and global impressions. There was, however, no meaningful improvement in other motor aspects of the disease, and the total UPDRS part II (activities of daily living) score did not change. Adverse events, more common in ET patients, were generally mild and were usually eliminated by adjustment of the device parameters. CONCLUSIONS: Thalamic DBS is a safe and effective treatment of ET and the tremor of PD. In PD, its use should be limited to patients in whom high-amplitude tremor results directly in significant functional disability.

Vagus nerve stimulation (VNS) for treatment-resistant depression: efficacy, side effects, and predictors of outcome.

This open pilot study of vagus nerve stimulation (VNS) in 60 patients with treatment-resistant major depressive episodes (MDEs) aimed to: 1) define the response rate; 2) determine the profile of side effects; and, most importantly; 3) establish predictors of clinical outcome. Participants were outpatients with nonatypical, nonpsychotic, major depressive or bipolar disorder who had not responded to at least two medication trials from different antidepressant classes in the current MDE. While on stable medication regimens, the patients completed a baseline period followed by device implantation. A 2-week, single blind, recovery period (no stimulation) was followed by 10 weeks of VNS. Of 59 completers (one patient improved during the recovery period), the response rate was 30.5% for the primary HRSD(28) measure, 34.0% for the Montgomery-Asberg Depression Rating Scale (MADRAS), and 37.3% for the Clinical Global Impression-Improvement Score (CGI-I of 1 or 2). The most common side effect was voice alteration or hoarseness, 55.0% (33/60), which was generally mild and related to output current intensity. History of treatment resistance was predictive of VNS outcome. Patients who had never received ECT (lifetime) were 3.9 times more likely to respond. Of the 13 patients who had not responded to more than seven adequate antidepressant trials in the current MDE, none responded, compared to 39.1% of the remaining 46 patients (p =.0057). Thus, VNS appears to be most effective in patients with low to moderate, but not extreme, antidepressant resistance. Evidence concerning VNS' long-term therapeutic benefits and tolerability will be critical in determining its role in treatment-resistant depression.

Epidemiological characteristics of subarachnoid hemorrhage in an urban population.

Several risk factors for unfavorable outcome from subarachnoid hemorrhage (SAH) have been identified. The prevalence of such risk factors varies among ethnic groups and among men and women. The influence of ethnic background and gender as factors in the outcome after SAH has not been adequately studied and is the focus of the present investigation. Outcome in 145 consecutive patients was dichotomized as good and moderately disabled vs severely disabled, vegetative, and dead. A multiple logistic regression model was used to examine the factors of gender, ethnic group (white and non-white), age, admission neurological grade, pre-existing hypertension, and intravenous drug abuse. Our data reveal that hypertensive, white males, with a history of intravenous drug abuse, have a high risk of unfavorable outcome following SAH. These observations are important for the design and interpretation of future studies relating to SAH.

Alterations in the corticomotor evoked potential following spinal cord ischemia.

A simple yet reliable model of spinal cord ischemia has been previously developed by inserting a Swan-Ganz catheter into the abdominal aorta of rabbits and inflating the balloon just inferior to the renal arteries. Recent investigations have shown that paraplegia is consistently reproduced if the balloon remains inflated for 20 min after loss of the N3 component of the somatosensory evoked potential. Because of its high reliability, this model has been frequently and successfully used to determine the efficacy of pharmacological agents thought to provide protection against spinal cord ischemia. Results from the present report demonstrate that a similar degree of reliability can be achieved in this model for testing motor activity. A simple method of evoking highly reproducible motor potentials, that can be percutaneously recorded from the spinal cord in response to cortical stimulation, was developed. Predictable and repeatable changes in the configuration of the corticomotor evoked potential were found during spinal cord ischemia and reperfusion. With this added dimension of functional assessment, future application of the current spinal cord ischemia model have been greatly expanded.

Ketamine suppresses c-fos expression in dorsal horn neurons after acute constrictive sciatic nerve injury in the rat.

Fos immunoreactivity within the spinal cord in a model of neuropathic pain was studied. Dorsal horn neurons in laminae I and II exhibited selective expression within the tibial, peroneal and posterior cutaneous nerve territories which, in turn, was suppressed during ketamine but not halothane anesthesia. Fos immunoreactive neurons have a unique response pattern to neuropathic pain which is sensitive to ketamine.

Noxious thermal stimulation of c-fos activity induced in rat lumbar spinal cord is reduced by AP-5 but not by glycine.

The effects of intrathecal administration of NMDA (N-methyl-D-aspartic acid) receptor antagonist AP-5 (2-Amino-5-phosphonopentanoic acid), a competitive and specific NMDA antagonist, and glycine on the neuronal expression of c-fos protein (Fos) in the dorsal neurons lumbar segments four and five were studied after noxious heat stimulation. Heat (52 degrees C, 3 s per application, repeated 10 times) was applied to the hindpaws of rats. NMDA receptor antagonist AP-5 (0.1 mmol/10 ml, i.t.) suppressed the noxious heat-induced Fos immunoreactivity by 65% as compared to animals pre-treated with saline. In contrast, glycine (0.1 micromol/10 microl, it.) did not influence Fos expression induced by the noxious heat stimulation. This study suggests that excitatory amino acids, e.g. glutamate but not the inhibitory aminos acid, glycine, plays a role in thermal nociception which in turn is mediated, in part, by c-fos activity.

Antisense of c-fos gene attenuates Fos expression in the spinal cord induced by unilateral constriction of the sciatic nerve in the rat.

Sciatic nerve constriction induces expression of c-fos protein in dorsal horn neurons of the spinal cord. Intrathecal administration of c-fos antisense (30 nmol/20 microl) into the lumbar region (L1-L5) 18 h prior to nerve ligation attenuated 80% of Fos-immunoreactivity 90 min after ligation compared to rats infused with c-fos sense or saline. Thus, c-fos antisense may be a useful tool in assessing the role of the c-fos gene in an animal model of neuropathic pain.

Corticomotor evoked potentials in acute and chronic blunt spinal cord injury in the rat: correlation with neurological outcome and histological damage.

Somatosensory evoked potentials (SSEPs) and corticomotor evoked potentials (CMEPs) were utilized to study acute and chronic blunt spinal cord trauma. Rats, anesthetized with ketamine hydrochloride, were subjected to parasagittal craniectomies and midthoracic laminectomies. SSEPs were cortically recorded and CMEPs were transcortically produced using epidural ball and disc electrodes. SSEPs were elicited and CMEPs were recorded via hindlimb percutaneous needle electrodes. After control records, animals were subjected to a 50-g/cm impact to the dorsal cord surface using a modified weight drop technique. Evaluation of neurological injury was performed by SSEP and CMEP analysis and was compared with neurological assessments obtained before injury and 1 hour, 1 week, 3 weeks, and 6 weeks after injury. Neurohistopathological verification of each spinal cord lesion was performed at 6 weeks after injury. Animals subjected to a 50-g/cm cord impact showed no change in SSEP wave forms, but all components of the CMEP were greatly attenuated with this injury. Acutely, either very weak movement or no movement to noxious stimulation was present without vocalization. There was a spectrum of clinical recovery that correlated closely with the return and normalization of the amplitude of the CMEP in 100% of the animals tested. The eventual degree of clinical and CMEP improvement correlated well with the degree of histological damage present. The results of this study suggest that the CMEP is a reliable indicator of the initial degree of loss of neurological motor function in acute blunt spinal cord injury in the rat, as well as an accurate measure of the degree and extent of recovery. The rat model as outlined here is a simple and inexpensive system for evaluation both clinically and electrophysiologically of the degree of motor recovery from spinal cord injury. This model should prove useful in the evaluation of promising pharmacological agents for potential use in the treatment of acute spinal cord injury.

Corticomotor and somatosensory evoked potential evaluation of acute spinal cord injury in the rat.

Somatosensory evoked potentials (SSEPs) and corticomotor evoked potentials (CMEPs) were utilized to study acute blunt spinal cord trauma. Rats, anesthetized with ketamine hydrochloride, were subjected to a parasagittal craniotomy and a midthoracic laminectomy. SSEPs were cortically recorded and CMEPs were transcortically produced using epidural ball and disc electrodes. SSEPs were elicited and CMEPs were recorded via hindlimb percutaneous needle electrodes. After control records were made, animals were subjected to a 25-, 50-, or 75-g/cm impact to the dorsal cord surface via a modified weight drop procedure. Evaluation of neurological injury was made by SSEP and CMEP analysis as well as by physical testing with noxious stimulation applied to the hindlimb. Neurohistopathological verification of each spinal cord lesion was performed. No significant change in SSEP configuration was identified in animals subjected to a 25-g/cm cord impact; however, a small decrement in CMEP amplitude was consistently observed. Although vocalization to noxious stimulation was present, flexion activity was less than normal. Animals subjected to a 50-g/cm cord impact also showed no change in SSEP wave forms. All components of the CMEP were greatly attenuated with this injury. Either very weak movement or no movement to noxious stimulation was present without vocalization. After a 75-g/cm cord impact, both SSEPs and CMEPs were abolished. There was no movement or vocalization in response to noxious stimulation. Serial sections of the spinal cords revealed incremental destruction with increasing severity of injury. These results support the hypothesis that CMEPs are a more sensitive indicator of residual spinal cord function after injury than are SSEPs.

Penetrating injuries restricted to the cauda equina: a retrospective review.

Thirty-three patients with penetrating injuries to the cauda equina were admitted to Ben Taub General Hospital (1980-1989). Thirty received gunshot injuries, and three had stab wounds. The average age was 30 years, and 30 patients were male. All patients had been admitted within 1 hour of injury and received spine films, myelography, or computed tomography. Deficits were "complete" if total loss of function existed and were "incomplete" if any function remained below the level of injury. Improvement at the end of followup was defined as any recovery of motor strength or regaining of a unilateral sensory level. Twenty-nine (88%) patients had incomplete neurological deficits. Of these, 15 (52%) had surgery, and of this patient group, 7 (47%) improved, 7 (47%) showed no change, and 1 (6%) worsened. Fourteen (48%) patients with incomplete deficits were treated conservatively; 10 (71%) improved, and 4 (29%) had no change. Four patients (12%) had complete deficits, 3 of whom had surgery, and all improved. One patient with a complete deficit was treated conservatively and did not improve. Ten (34%) patients had bowel or bladder dysfunction, and none improved regardless of the type of treatment. Complications (cerebrospinal fluid leak, pseudomeningocele, or wound infection) occurred in 5 (28%) operative patients and 1 (7%) conservatively treated patient. Early neurosurgical intervention for penetrating injuries of the cauda equina may be beneficial but carries an increased risk of complication.

Concepts and methods in chronic thalamic stimulation for treatment of tremor: technique and application.

OBJECTIVE: To rationalize the technique and reduce the costs associated with chronic deep brain stimulation of the thalamus for treatment of refractory tremor. METHODS: The efficacy and safety of a modification in surgical techniques was prospectively assessed in 94 patients with tremor. Bilateral electrodes were implanted in 29 patients, and 65 patients received unilateral implants. Forty-five patients had Parkinson's disease tremor, 42 patients had essential tremor, and 7 patients had kinetic tremors of different causes. In all instances, intraoperative stimulations to analyze the thresholds of intrinsic and extrinsic responses were performed directly with the implanted leads. The electrodes were repositioned until satisfactory results were achieved. The pulse generators were implanted directly after the first step in the same operative session. Patients were not subjected to interoperative test stimulation trials. RESULTS: Postoperative improvement of tremor at a mean follow-up of 11.9 months was rated as excellent in 47 patients (50%), marked in 37 patients (39%), moderate in 8 patients (9%), and minor in 2 patients (2%). There was no persistent morbidity related to surgery. In patients with Parkinson's disease, the symptomatic improvement of tremor was rated as excellent in 51% of patients, marked in 36%, moderate in 11%, and minor in 2%. In patients with essential tremor, symptomatic outcome was classified as excellent in 57% of patients, marked in 36%, moderate in 5%, and minor in 2%. Six of the seven patients with kinetic tremor achieved marked symptomatic improvement, and one patient experienced moderate improvement. Forty patients experienced stimulation-related side effects. Side effects were mild in general, and they were reversible with a change in electrical parameters. They occurred more frequently in patients who had bilateral stimulation. CONCLUSION: Excellent to marked improvement of tremor is achieved in the majority of patients with physiological target determination via implanted leads in thalamic deep brain stimulation. Interoperative test stimulation trials are unnecessary. Modifications in technique may help to reduce the costs of the related hospital stay.

Transdermal fentanyl as treatment for chronic low back pain.

Management of chronic low back pain often includes oral opioid use. The effectiveness of therapy is dependent upon compliance, which in turn is dependent upon response, side effects, access, and convenience. Our hypothesis was that a transdermal fentanyl system would provide more effective pain management than oral opioids. Fifty patients with chronic low back pain were examined. After litration to levels corresponding to current oral opioid use, each patient was maintained on transdermal fentanyl for one month. Oral opioid therapy was then resumed. Their experience was assessed with the a visual analogue scale for pain intensity, a numerical pain score, the Oswestry disability questionnaire, the pain disability index, and the Verran Snyder-Halpern sleep scale. Significant improvement in pain relief and disability was found with transdermal fentanyl compared with oral opioids. Mild opioid side effects were common, but easily controlled. Use of transdermal fentanyl is an effective alternative to oral opioids for managing chronic low back pain.

Distal posterior cerebral artery aneurysm. Case report.

A case of an unusual distal posterior cerebral artery (PCA) aneurysm is presented. The saccular aneurysm arose from a fetal PCA distal to the posterior temporal branch of the P3 segment. The aneurysm was treated by placing a clip on the PCA distal to the anterior temporal branch of the P2 segment. A ventriculoperitoneal shunt was also placed. The patient's postoperative recovery was unremarkable and without residual neurological deficit. The highly unusual location of this aneurysm is discussed and the neurosurgical literature is reviewed in detail.

Neurosurgical intervention in penetrating spinal trauma with associated visceral injury.

Associated injuries to the neck, chest, or abdomen are found in approximately one-quarter of all civilians with penetrating spinal cord or cauda equina injuries. While the value of and indications for general surgical exploration and repair of these injuries are fairly self-evident, the value of neurosurgical intervention in terms of neurological outcome and infection prophylaxis remains the subject of debate. To study this issue, 160 civilian patients with penetrating spinal injuries and neurological deficits were retrospectively reviewed. Associated injuries of the esophagus, trachea, bronchi, or bowel were seen in 107 individuals (67%); 33 (31%) of these patients had abdominal injuries, 25 (23%) had neck injuries, 23 (21%) had thoracic injuries, and 26 (24%) had injuries occurring at multiple sites. Of these 107 patients, 67 (63%) had complete neurological injuries and the remaining 40 (37%) demonstrated incomplete deficits. All 107 patients underwent surgical exploration and repair of their visceral injuries; in 19 of them a neurosurgical procedure was also performed for decompression of the neural elements and/or debridement of the wound. Regardless of the presence of associated visceral injuries, the mechanism of injury, and the extent of the neurological deficit, no statistically significant difference in neurological outcome was found in patients with or without neurosurgical intervention. Complications associated with neurological injury were reported in 17 (11%) of the total group of 160 patients. Four (21%) of the 19 patients who had neurosurgical intervention suffered a related complication, compared to only six (7%) of the 88 patients who were managed conservatively (p less than 0.05). Within the limitations of a retrospective review, the results of this study do not clearly support the value of routine neurosurgical intervention as an adjunct to general surgical repair in cases of spinal injury associated with penetrating visceral trauma.

Emergency balloon occlusion for massive epistaxis due to traumatic carotid-cavernous aneurysm. Case report.

A patient with a giant traumatic aneurysm of the right internal carotid artery presented with recurrent massive epistaxis 30 years after a head injury. During an episode of acute hemorrhage, this patient was effectively treated with occlusion of the internal carotid artery circulation by a detachable inflatable balloon.

Neurosurgical management of carotid sinus hypersensitivity. Report of three cases.

Carotid sinus hypersensitivity (CSH) can cause severe bradycardia, hypotension, asystole, and cardiac arrest. Three patients with the combined (mixed) cardioinhibitory and vasodepressor form of CSH were studied with intensive cardiovascular monitoring. After medical management failed, the patients were successfully treated by transection of the glossopharyngeal nerve and upper rootlets of the vagus nerve at their exit from the brain stem. Methods of diagnosis of CSH, and the benefits and limitations of medical and surgical therapies are discussed.