Magnetoencephalography in the presurgical evaluation of epilepsy.

Magnetoencephalography (MEG) is an important tool in the presurgical evaluation of patients with medically refractory epilepsy. The appropriate utilization and interpretation of MEG studies can increase the proportion of patients who may be able to further pursue surgical evaluation, refine surgical planning, and potentially increase the probability of seizure freedom after surgery. The aim of this paper is to provide the reader with a comprehensive but accessible guide to MEG, with particular emphasis on acquiring a working knowledge of MEG analysis, identifying patient groups that are most likely to benefit, and clarifying the limitations of this technology.

Accuracy of percutaneous placement of a ventriculoatrial shunt under ultrasonography guidance: a retrospective study at a single institution.

The authors report their experience using preoperative chest radiography and intraoperative ultrasonography for percutaneous positioning of the distal end of the catheter when placing ventriculoatrial (VA) shunts in patients with hydrocephalus. The distal portion of VA shunt catheters were percutaneously placed into the internal jugular vein with the aid of intraoperative ultrasonography in 14 consecutive adults. In all cases, the technique was easy, there were no postoperative complications, and postoperative chest radiography demonstrated good positioning of the distal catheter tip. One patient presented with a shunt infection and needed a shunt replacement. The authors therefore conclude that percutaneous placement of a VA shunt under preoperative radiographic guidance and ultrasonographic monitoring is a safe, effective, and reliable technique that is simple to learn.

Changes in Parkinson's disease sleep symptoms and daytime somnolence after bilateral subthalamic deep brain stimulation in Parkinson's disease.

INTRODUCTION: Deep brain stimulation (DBS) markedly improves motor function in advanced Parkinson's disease (PD), but its effect on sleep is less clear. PATIENTS AND METHODS: Forty PD patients who had subthalamic DBS (STN-DBS) were identified from an on-going non-motor naturalistic longitudinal study (NILS). All patients were followed up for at least 6 months, 26 patients had a 1 year follow-up. A total PDSS score of 100 or less, a score in any PDSS-item of 6 or less, and a Epworth score of 10 or more were classified as being significant. RESULTS: Forty-five percent of patients reported significant improvement in the total PDSS score at 6 months, and 35% at 12 months. In terms of magnitude, the total PDSS score at 6 months was significantly improved from baseline while the improvement at 12 months was not statistically significant. The most frequently reported improvements were overall sleep quality and maintenance of sleep. Some patients reported worsening of the total PDSS score. More than half of the patients reporting daytime sleepiness at baseline had persistent sleepiness at 6 and 12 months. The mean Epworth Score did not improve because a significant number of patients without sleepiness at baseline reported new-onset sleepiness at 6 and 12 months. Neither medication changes nor motor improvement were consistently related to sleep changes after DBS. CONCLUSION: Subthalamic DBS is associated with a statistically and clinically significant, but variable, improvement in sleep as measured by the PDSS. The most frequent improvements were better overall sleep quality and better sleep maintenance.

Characteristics and reversibility of dementia in Normal Pressure Hydrocephalus.

Studies of the cognitive outcome after shunt insertion for treatment of Normal Pressure Hydrocephalus have reported widely mixed results. We prospectively studied performance of 60 patients with Normal Pressure Hydrocephalus on a comprehensive battery of neuropsychological tests before and after shunt surgery to determine which cognitive functions improve with shunt insertion. We also administered a subset of cognitive tests before and after temporary controlled drainage of cerebrospinal fluid to determine if change on this brief subset of tests after drainage could predict which patients would show cognitive improvement three to six months after shunt insertion. There was a significant improvement in learning, retention, and delayed recall of verbal memory three to six months after surgery (using paired t-tests). The majority (74%) of patients showed significant improvement (by at least one standard deviation) on at least one of the memory tests. Absence of improvement on verbal memory after temporary drainage of cerebrospinal fluid had a high negative predictive value for improvement on memory tests at 3-6 months after surgery (96%; p=0.0005). Also, the magnitude of improvement from Baseline to Post-Drainage on few specific tests of learning and recall significantly predicted the magnitude of improvement after shunt surgery on the same tests (r2=0.32-0.58; p=0.04-0.001). Results indicate that testing before and after temporary drainage may be useful in predicting which patients are less likely to improve in memory with shunting.

Socio-demographic influences on epilepsy outcomes in an inner-city population.

PURPOSE: Previous studies show anti-epileptic drug compliance and seizure control in people with epilepsy (PWE) to be lower among low-income groups and African-Americans. We examined how socio-demographic factors influence seizure control in an inner-city population. METHODS: The clinic records of 193 PWE were analyzed. Good seizure control was defined as no seizures in the previous year. Bivariate and multivariate analyses were performed to examine the effects of race, age, gender, median household income, medication cost, and insurance status on good seizure control. RESULTS: There were 69 Caucasians and 124 African-Americans (age 47.8±16.5 years) in the study. African Americans had a significantly lower income than Caucasians (p<0.001); but did not have inferior seizure control (p=0.18). Seizure control was also not affected by gender (p=0.82), AED costs (p=0.06), insurance type (p=0.20), or race-independent household income (p=0.75). CONCLUSION: Contrary to prior literature, we find that in our population of PWE there were no significant effects of race or family income on seizure outcomes. Our findings add to the existing literature on socio-demographic disparities in PWE and merit further exploration by other groups.

Skin biopsy in complex regional pain syndrome: case series and literature review.

BACKGROUND: Accumulating experimental and clinical evidence supports the hypothesis that complex regional pain syndrome type I (CRPS-I) may be a small fiber neuropathy. OBJECTIVES: To evaluate the use of commercially available standard biopsy methods to detect intradermal axon pathology in CRPS-I, and to ascertain if these structural changes can explain quantitative sensory testing (QST) findings in CRPS-I. STUDY DESIGN: Retrospective review of charts and laboratory data. SETTING: Outpatient clinic METHODS: Skin biopsies from 43 patients with CRPS-I were stained with PGP 9.5, and epidermal nerve fiber density, sweat gland nerve fiber density and morphological abnormalities were evaluated. Thirty-five patients had quantitative sensory testing. RESULTS: Alterations in skin innervation were seen in approximately 20% of CRPS-I patients with commercial processing. There were no patient characteristics, including duration of disease, that predicted a decreased epidermal nerve fiber density (ENFD). There was no consistent relationship between QST changes and ENFD measured by standard commercial skin biopsy evaluation procedures. LIMITATIONS: Commercial processing of tissue does not utilize stereologic quantitative analysis of nerve fiber density. Biopsy material is utilized from a proximal and distal source only, and differences in denervation of a partial nerve territory may be missed. The functional attributes of small fibers cannot be assessed. CONCLUSIONS: The negative results indicate that CRPS-I may be associated with changes in the ultramicroscopic small fiber structure that cannot be visualized with commercially available techniques. Alternatively, functional rather than structural alterations of small fibers or pathological changes at a more proximal site such as the spinal cord or brain may be responsible for the syndrome.

Intramuscular botulinum toxin in complex regional pain syndrome: case series and literature review.

BACKGROUND: Pain associated with Complex Regional Pain Syndrome (CRPS) is frequently excruciating and intractable. The use of botulinum toxin for relief of CRPS-associated pain has not been well described. OBJECTIVES: To assess whether intramuscular botulinum toxin injections cause relief of pain caused by CRPS, and to assess the risks of this treatment. STUDY DESIGN: Retrospective chart review. SETTING: Outpatient clinic. METHODS: 37 patients with spasm/dystonia in the neck and/or upper limb girdle muscles. INTERVENTION: EMG-guided injection of Botulinum Toxin - A (BtxA), 10-20 units per muscle. Total dose used was 100 units in each patient. Local pain score was measured on an 11-point Likert scale, 4 weeks after BtxA injections. RESULTS: Mean pain score decreased by 43% (8.2 ± 0.8 to 4.5 ± 1.1, P < 0.001). 97% patients had significant pain relief. One patient had transient neck drop after the injections. LIMITATIONS: This is a retrospective study, it lacks a control group and hence the placebo effect cannot be eliminated. This study does not provide information on the efficacy of this treatment after 4 weeks. CONCLUSIONS: Intramuscular injection of botulinum toxin in the upper limb girdle muscles was beneficial for short term relief of pain caused by CRPS. The incidence of complications was low (2.7%).

Intramuscular botulinum toxin A (BtxA) in complex regional pain syndrome.

BACKGROUND: Pain associated with complex regional pain syndrome (CRPS) is frequently excruciating and intractable. The use of botulinum toxin for relief of CRPS-associated pain has not been well described. OBJECTIVES: To assess whether intramuscular botulinum toxin injections cause relief of pain caused by CRPS, and to assess the risks of this treatment. STUDY DESIGN: Retrospective chart review. SETTING: Outpatient clinic. PATIENTS: 37 patients with spasm/dystonia in the neck and/or upper limb girdle muscles. INTERVENTION: Electromyography-guided injection of botulinum toxin A (BtxA), 10-20 U per muscle. Total dose used was 100 U in each patient. MEASUREMENT: Local pain score on an 11 point Likert scale, 4 weeks after BtxA injections. RESULTS: Mean pain score decreased by 43% (8.2 ± 0.8 to 4.5 ± 1.1, P < 0.001). Ninety-seven percent of the patients had significant pain relief. One patient had transient neck drop after the injections. LIMITATIONS: This is a retrospective study; it lacks a control group and therefore the placebo effect cannot be eliminated. This study does not provide information on the efficacy of this treatment after 4 weeks. CONCLUSION(S): Intramuscular injection of botulinum toxin A in the upper limb girdle muscles was beneficial for short term relief of pain caused by CRPS in this retrospective case series. The incidence of complications was low (2.7%).

Cognitive impairment in patients with Pseudotumor Cerebri Syndrome.

INTRODUCTION: Patients with Pseudotumor Cerebri Syndrome (PTCS) may complain of difficulty in thinking or concentrating; however there has been little formal cognitive evaluation in this population. OBJECTIVE: To evaluate the characteristics and nature of cognitive impairment in patients with PTCS. METHODS: We retrospectively reviewed records of 10 patients diagnosed with PTCS who were cognitively tested at presentation. In each cognitive test, "Borderline deficit" (BD) was defined as a score more than 1 standard deviation (SD) below and "Definite Deficit" (DD) as a score more than 2 SD below the mean for age, sex and education. In each cognitive domain, impairment was defined as a single test score more than 2 SD below the mean, or scores of more than 1 SD below the mean for age, sex and education in > 50% of tests. RESULTS: Mean age of patients was 43.4 ± 13.5 years. 8/10(80%) patients were female. 3/10(30%) had papilledema; 3/10(30%) had significant cerebral venous outflow obstruction. Impairment was most commonly seen and was most severe in the WMS logical memory I (BD-44%, DD-44%), WMS logical memory II (BD-37.5%, DD-50%), RAVLT delayed recall (BD-30%, DD-40%) and RAVLT retention(BD-40%, DD-30%) tests. Evaluation of cognitive domains revealed impairment in memory and learning (80%), executive function (10%), visuo-spatial skills (30%), and language (30%). CONCLUSION: Our results indicate that patients with PTCS can have significant cognitive impairment, particularly in learning and memory. The prevalence needs to be studied in a larger cohort. The relationship of cognitive impairment with chronically elevated intracranial pressures and its role in contributing to patient morbidity needs to be investigated further.

Fractionated conformal radiotherapy for management of optic nerve sheath meningiomas: long-term outcomes of tumor control and visual function at a single institution.

PURPOSE: To provide the long-term outcomes of patients treated with fractionated conformal radiotherapy (FCRT) for presumed optic nerve sheath meningiomas (ONSMs). PATIENTS AND METHODS: Between 1995 and 2002, 9 patients with a presumed ONSM were treated with FCRT at our institution. The indications for FCRT were significant visual dysfunction at presentation, progression of visual dysfunction during a period of observation, tumor growth documented by sequential imaging, or a combination of these findings. In 2 patients, FCRT was performed as adjuvant therapy, and in 7, it was the initial and primary treatment. RESULTS: Of the 9 patients, 6 were women and 3 were men, with a mean age of 47 years. All 9 patients had evidence of optic nerve dysfunction in the affected eye, characterized by reduced visual acuity, a visual field defect, and a relative afferent pupillary defect. In addition, 2 patients had proptosis and 1 had diplopia. The mean follow-up period was 98 ± 31.7 months (median, 90; range, 61-151). After FCRT, the visual function improved in the 7 patients who had undergone FCRT as the primary treatment. However, 2 patients who were blind in their affected eye at FCRT remained blind. In 4 of the 7 patients with improvement, the improvement was documented within 1-3 months after FCRT. The tumor control rate was 100%. Proptosis and diplopia also regressed in 100% of patients. At 2 years after FCRT, 1 patient had developed radiation retinopathy. CONCLUSION: The results of our study have shown that FCRT is a safe and effective treatment of ONSMs, affording satisfactory long-term tumor control, good functional outcome, and low treatment morbidity. FCRT should be considered the treatment of choice for patients with presumed ONSMs for whom the treatment has been deemed appropriate.

Long-term outcomes of vestibular schwannomas treated with fractionated stereotactic radiotherapy: an institutional experience.

PURPOSE: We assessed clinical outcome and long-term tumor control after fractionated stereotactic radiotherapy (FSRT) for unilateral schwannoma. METHODS AND MATERIALS: Between 1995 and 2007, 496 patients were treated with fractionated stereotactic radiotherapy at Johns Hopkins Hospital (Baltimore, MD); 385 patients had radiologic follow-up that met the inclusion criteria. The primary endpoint was treatment failure. Secondary endpoints were radiologic progression and clinical outcome. Logistic regression analysis assessed the association of age, race, tumor side, sex, and pretreatment symptoms. RESULTS: In 11 patients (3%) treatment failed, and they required salvage (microsurgical) treatment. Radiologic progression was observed in 116 patients (30.0%), including 35 patients (9%) in whom the treatment volume more than doubled during the follow-up period, although none required surgical resection. Tumors with baseline volumes of less than 1 cm(3) were 18.02 times more likely to progress than those with tumor volumes of 1 cm(3) or greater (odds ratio, 18.02; 95% confidence interval, 4.25-76.32). Treatment-induced neurologic morbidity included 8 patients (1.6%) with new facial weakness, 12 patients (2.8%) with new trigeminal paresthesias, 4 patients (0.9%) with hydrocephalus (1 communicating and 3 obstructive), and 2 patients (0.5%) with possibly radiation-induced neoplasia. CONCLUSIONS: Although the rate of treatment failure is low (3%), careful follow-up shows that radiologic progression occurs frequently. When reporting outcome, the "no salvage surgery needed" and "no additional treatment needed" criteria for treatment success need to be complemented by the radiologic data.

Radionuclide shunt patency study for evaluation of suspected ventriculoperitoneal shunt malfunction in adults with normal pressure hydrocephalus.

OBJECTIVE: Shunt patency studies are performed to determine whether shunt revision surgery is needed in malfunctioned ventriculoperitoneal shunt. The aim of our study was to develop a simple diagnostic algorithm in the diagnostic workup and identify factors associated with improvement after revision surgery. METHODS: A retrospective review of patients with confirmed shunt obstruction who underwent a revision surgery and were followed for 6 to 12 months was performed. A simpler algorithm to identify shunt obstruction was created and compared with the 4-variable algorithm. RESULTS: Of the 63 patients in whom shunt obstruction was suspected, 39 were diagnosed with complete or partial obstruction. Thirty-seven patients underwent shunt revision surgery that included removal of shunt (n = 2), conversion to a ventriculoatrial shunt (n = 8), and relocation of the distal end of the catheter into a different part of the peritoneal cavity (n = 27). Improvements were seen in 63.3% (n = 19) of patients evaluated at 6 months and 63.6% (n = 14) of patients evaluated at 12 months. The positive predictive value of the study was 80%. A simpler 1-variable algorithm using T(1/2) (half-time) could correctly classify 86.9% of patients with shunt obstruction, compared with a 4-variable algorithm that correctly classified 80% of patients. CONCLUSION: Shunt patency studies are very useful for evaluation of shunt patency. Their results can be interpreted using a single-variable (T(1/2)) algorithm. Patients most likely to respond to a revision surgery are those who had a good response to original placement of a ventriculoperitoneal shunt.

Objective assessment of gait in normal-pressure hydrocephalus.

OBJECTIVES: Gait abnormalities are an early clinical symptom in normal pressure hydrocephalus (NPH), and subjective improvement in gait after temporary removal of CSF is often used to decide to perform shunt surgery. We investigated objective measures to compare gait before and after CSF drainage and shunt surgery. DESIGN: Twenty patients and nine controls were studied. Quantitative gait measures were obtained at baseline, after 3 days of controlled CSF drainage, and after shunt surgery. Decision to perform surgery was based on response to drainage, and patients were assigned to shunted or unshunted groups for comparison. RESULTS: There was no improvement after CSF drainage in the unshunted group (n = 4). In the shunted group (n = 15) velocity, double-support time, and cadence improved significantly after drainage, and improved further after shunt surgery. The degree of improvement after drainage significantly correlated to the degree of improvement postshunt for velocity, double-support time, cadence, and stride length. CONCLUSIONS: There are significant, quantifiable changes in gait after CSF drainage that correspond to improvement after shunt surgery for patients with NPH. Use of objective gait assessment may improve the process of identifying these candidates when response to CSF removal is used as a supplemental prognostic test for shunt surgery.

The natural history of conservatively managed symptomatic intramedullary spinal cord cavernomas.

OBJECTIVE: The presentation and natural history of untreated, symptomatic intramedullary spinal cavernomas at our institution were analyzed. The objective is to provide additional information regarding the natural history of conservatively managed, symptomatic, intramedullary spinal cord cavernous malformations. METHODS: The medical records of patients treated in our institution between 1989 and 2002 were reviewed to identify those with intramedullary cavernomas. The medical, radiological, surgical, and pathological records from these patients were retrospectively reviewed and analyzed. RESULTS: Fourteen patients were included in the study. The mean age at presentation was 42 years. Four lesions (29%) were located in the cervical region and 10 lesions (71%) were present in the thoracolumbar spinal cord. All patients were symptomatic at the time of presentation. In this cohort of 14 patients, 10 patients (71%) were conservatively managed. For these patients, the mean duration of symptoms before presentation was 10 months. The mean duration of follow-up from the time of presentation was 80 months. The median McCormick grade for conservatively treated patients at presentation was II. During this period, none of the conservatively managed patients had an acute intramedullary bleed. In nine patients, the McCormick grade at the last follow-up evaluation was the same as or better than their score at presentation. Four patients (29%) were treated surgically. The mean duration of symptoms before presentation was 33 months. The mean duration of follow-up from the time of presentation was 42 months. In two surgical patients, the McCormick grade at the last follow-up evaluation remained unchanged compared with their score at presentation, whereas the McCormick grade improved in one patient and deteriorated in another patient. CONCLUSION: This cohort of conservatively managed patients with symptomatic, intramedullary spinal cord cavernomas was clinically stable throughout the follow-up period. In this series, patients harboring symptomatic spinal cord cavernous malformation did not have significant, permanent neurological decline during the follow-up period when treated with the conservative approach of observation. This data provides additional information for determining the appropriate treatment strategy for patients with intramedullary spinal cavernomas.

Evaluation and treatment of patients with suspected normal pressure hydrocephalus on long-term warfarin anticoagulation therapy.

OBJECTIVE: Long-term anticoagulation is often considered a contraindication to shunt surgery for elderly patients with normal pressure hydrocephalus (NPH). However, no studies have investigated this question. METHODS: We evaluated 25 patients who were taking warfarin for NPH between 2001 and 2004 with a protocol of cerebrospinal fluid (CSF) pressure monitoring and controlled CSF drainage via spinal catheter. Warfarin was stopped 5 to 7 days before lumbar puncture or shunt surgery and restarted 3 to 5 days after operation or at the time of discharge from the hospital. Programmable shunts with antisiphon devices set at the high-pressure range were preferentially used and adjusted in small increments. RESULTS: After CSF drainage, 16 patients showed improvement and 15 underwent shunt surgery. Thirteen (87%) out of these 15 patients showed significant improvement in at least one symptom during a mean follow-up period of 8.2 months (range, 1-70 mo) after shunt surgery. There were two bleeding complications. One patient (6.7%) with cirrhosis who developed a subdural hematoma 13 days after operation had the shunt removed; another patient who developed an abdominal subcutaneous hematoma 5 days after operation required surgical evacuation and shunt revision surgery. Otherwise, 14 (93.3%) out of the 15 patients had no subdural hematoma during the follow-up period and there were no thromboembolic complications while the patients were not taking warfarin. CONCLUSION: Elderly patients on long-term warfarin anticoagulation can be safely evaluated and treated for NPH using a protocol of continuous CSF drainage via spinal catheter for diagnosis, cautious periprocedural management of anticoagulation, and use of programmable shunts with antisiphon devices. The risk of subdural hematoma is not higher than reported series. Long-term anticoagulation with warfarin is not a contraindication per se for shunt surgery in NPH.