Impact of selective dorsal rhizotomy to cerebral palsy children caregivers' burden.

PURPOSE: It is known that cerebral palsy (CP) children's caregivers suffer from burden, depression, and stress, impairing their quality of life (QoL). The more severe the CP, the more burden the caregiver has. Psychosocial support, education, therapies, and financial support are inversely related to the level of stress of the caregiver. Most parents of CP patients submitted to selective dorsal rhizotomy (SDR) report improvement not just on spasticity, but also in the functional role of the children, what can impact on caregiver's QoL. Our objective was to evaluate the burden of CP children's caregivers with and without previous SDR. METHODS: Spastic CP children caregivers were divided into two groups: those who take care of children without previous SDR (control group) and those that children were previously submitted to SDR (surgical group). The burden index was compared between groups using Burden Interview Questionnaire (BIQ). For statistical analysis, we used SPSS. RESULTS: The control group had enrolled 31 participants and the surgical group 36. The mean GMFCS level on the control and surgical groups was 3.94 ± 1.26 and 3.74 ± 1.12 (p = 0.61), respectively. The surgical group caregivers presented less burden related to the feeling that they should be doing more to their child (p = 0.003) and if they could do a better job in caring (p = 0.032), compared to controls. The total BIQ index was not significantly different between groups (surgical 32.14 ± 12.34 vs. control 36.77 ± 12.77; p = 0.87). Low economic status had a weak correlation to a higher BIQ index (R2 = 0.24). After age-matching, there was a significative higher BIQ index in the control group (p = 0.008). CONCLUSION: Caregivers of spastic CP children who were previously submitted to SDR presented less burden related to feeling of the amount of given care than those without previous surgery. The impression that they could do a better job with their kids was higher in the control group. The severity of CP and low economic status were related to more burden in both groups. After pairing groups by age, the control group had a significative higher BIQ index compared to the SDR group. CLINICAL TRIAL REGISTRATION: Trial registration number: CAAE 73407317.6.0000.0068 (Ethical and Research Committee of University of Sao Paulo, Sao Paulo, Brazil, approved on 08/06/2021). All the subjects were freely given an informed consent to participate in the study that was obtained from all participants. Non-consented ones were excluded from the study.

Training with noninvasive brain-machine interface, tactile feedback, and locomotion to enhance neurological recovery in individuals with complete paraplegia: a randomized pilot study.

In recent years, our group and others have reported multiple cases of consistent neurological recovery in people with spinal cord injury (SCI) following a protocol that integrates locomotion training with brain machine interfaces (BMI). The primary objective of this pilot study was to compare the neurological outcomes (motor, tactile, nociception, proprioception, and vibration) in both an intensive assisted locomotion training (LOC) and a neurorehabilitation protocol integrating assisted locomotion with a noninvasive brain-machine interface (L + BMI), virtual reality, and tactile feedback. We also investigated whether individuals with chronic-complete SCI could learn to perform leg motor imagery. We ran a parallel two-arm randomized pilot study; the experiments took place in São Paulo, Brazil. Eight adults sensorimotor-complete (AIS A) (all male) with chronic (> 6 months) traumatic spinal SCI participated in the protocol that was organized in two blocks of 14 weeks of training and an 8-week follow-up. The participants were allocated to either the LOC group (n = 4) or L + BMI group (n = 4) using block randomization (blinded outcome assessment). We show three important results: (i) locomotion training alone can induce some level of neurological recovery in sensorimotor-complete SCI, and (ii) the recovery rate is enhanced when such locomotion training is associated with BMI and tactile feedback (∆Mean Lower Extremity Motor score improvement for LOC = + 2.5, L + B = + 3.5; ∆Pinprick score: LOC = + 3.75, L + B = + 4.75 and ∆Tactile score LOC = + 4.75, L + B = + 9.5). (iii) Furthermore, we report that the BMI classifier accuracy was significantly above the chance level for all participants in L + B group. Our study shows potential for sensory and motor improvement in individuals with chronic complete SCI following a protocol with BMIs and locomotion therapy. We report no dropouts nor adverse events in both subgroups participating in the study, opening the possibility for a more definitive clinical trial with a larger cohort of people with SCI.Trial registration: http://www.ensaiosclinicos.gov.br/ identifier RBR-2pb8gq.

Unilateral Campotomy of Forel for Acquired Hemidystonia: An Open-Label Clinical Trial.

BACKGROUND: Hemidystonia (HD) is characterized by unilateral involuntary torsion movements and fixed postures of the limbs and face. It often develops after deleterious neuroplastic changes secondary to injuries to the brain. This condition usually responds poorly to medical treatment, and deep brain stimulation often yields unsatisfactory results. We propose this study based on encouraging results from case reports of patients with HD treated by ablative procedures in the subthalamic region. OBJECTIVE: To compare the efficacy of stereotactic-guided radiofrequency lesioning of the subthalamic area vs available medical treatment in patients suffering from acquired HD. METHODS: This is an open-label study in patients with secondary HD allocated according to their treatment choice, either surgical or medical treatment; both groups were followed for one year. Patients assigned in the surgical group underwent unilateral campotomy of Forel. The efficacy was assessed using the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, Arm Dystonia Disability Scale, and SF-36 questionnaire scores. RESULTS: Patients in the surgical group experienced significant improvement in the Unified Dystonia Rating Scale, Fahn-Marsden Dystonia Scale, and Arm Dystonia Disability Scale (39%, 35%, and 15%, respectively) 1 year after the surgery, with positive reflex in quality-of-life measures, such as bodily pain and role-emotional process. Patients kept on medical treatment did not experience significant changes during the follow-up. No infections were recorded, and no neurological adverse events were associated with either intervention. CONCLUSION: The unilateral stereotaxy-guided ablation of Forel H1 and H2 fields significantly improved in patients with HD compared with optimized clinical treatment.

Dissecting neuropathic from poststroke pain: the white matter within.

ABSTRACT: Poststroke pain (PSP) is a heterogeneous term encompassing both central neuropathic (ie, central poststroke pain [CPSP]) and nonneuropathic poststroke pain (CNNP) syndromes. Central poststroke pain is classically related to damage in the lateral brainstem, posterior thalamus, and parietoinsular areas, whereas the role of white matter connecting these structures is frequently ignored. In addition, the relationship between stroke topography and CNNP is not completely understood. In this study, we address these issues comparing stroke location in a CPSP group of 35 patients with 2 control groups: 27 patients with CNNP and 27 patients with stroke without pain. Brain MRI images were analyzed by 2 complementary approaches: an exploratory analysis using voxel-wise lesion symptom mapping, to detect significant voxels damaged in CPSP across the whole brain, and a hypothesis-driven, region of interest-based analysis, to replicate previously reported sites involved in CPSP. Odds ratio maps were also calculated to demonstrate the risk for CPSP in each damaged voxel. Our exploratory analysis showed that, besides known thalamic and parietoinsular areas, significant voxels carrying a high risk for CPSP were located in the white matter encompassing thalamoinsular connections (one-tailed threshold Z > 3.96, corrected P value <0.05, odds ratio = 39.7). These results show that the interruption of thalamocortical white matter connections is an important component of CPSP, which is in contrast with findings from nonneuropathic PSP and from strokes without pain. These data can aid in the selection of patients at risk to develop CPSP who could be candidates to pre-emptive or therapeutic interventions.

Low health literacy and quality of life in patients with systemic arterial hypertension.

Purpose: Evaluate the level of health literacy and quality of life of patients with hypertension. Methods: A cross-sectional, observational study was carried out in the Northeast region of Brazil with 105 patients with hypertension through the SAHLPA-18, S-TOFHLA and MINICHAL tests. Results: For both literacy tests applied, it can be observed that about 60% of the interviewed patients did not present adequate health literacy. It was found that factors such as increasing age, lower economic class and lower education were associated with a lower level of health literacy. In the evaluation of the quality of life by the MINICHAL, 46.7% of the patients reported that hypertension interferes with quality of life. It was also possible to show that the time of diagnosis (p = 0.04) and the economic class (p = 0.008) influence the quality of life. Conclusion: Hypertension is a chronic condition that requires continuous treatment and has potential risks of evolving with fatal and non-fatal complications that can affect the patients' quality of life. The data presented reflect the difficulty in understanding and processing health information, which may directly impact on the therapeutic management of hypertension.

Concordance between two instruments for health literacy assessment. / Concordância entre dois instrumentos para avaliação do letramento em saúde.

OBJETIVO: To determine agreement between the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Short Assessment of Health Literacy for Portuguese-speaking Adults (SAHLPA-18) measurement instruments as a strategy for estimating concurrent validity. METHODS: This was a cross-sectional study conducted with users of the Brazilian National Health System. An agreement approach using a weighted Kappa test for qualitative data was applied in order to test for concurrent validity. RESULTS: 372 individuals participated. It was found that 66% and 62% of them did not have an adequate level of literacy according to SAHLPA-18 and S-TOFHLA, respectively. There was strong correlation between the instruments (p<0.001; r=0.60), although the 65.3% agreement of correct answers found was considered weak (Kappa=0.35; p<0.001). CONCLUSION: The SAHLPA-18 and S-TOFHLA instruments have different constructs and poor agreement. Use of different instruments is indicated in research intended to measure level of literacy, as is the development of instruments specific to health conditions that allow results close to the real context of individuals to be obtained.

Longitudinal Changes After Amygdala Surgery for Intractable Aggressive Behavior: Clinical, Imaging Genetics, and Deformation-Based Morphometry Study-A Case Series.

BACKGROUND: Intractable aggressive behavior (iAB) is a devastating behavioral disorder that may affect psychiatric patients. These patients have reduced quality of life, are more challenging to treat as they impose a high caregiver burden and require specialized care. Neuromodulatory interventions targeting the amygdala, a key hub in the circuitry of aggressive behavior (AB), may provide symptom alleviation. OBJECTIVE: To Report clinical and imaging findings from a case series of iAB patients treated with bilateral amygdala ablation. METHODS: This series included 4 cases (3 males, 19-32 years old) who underwent bilateral amygdala radiofrequency ablation for iAB hallmarked by life-threatening self-injury and social aggression. Pre- and postassessments involved full clinical, psychiatric, and neurosurgical evaluations, including scales quantifying AB, general agitation, quality of life, and magnetic resonance imaging (MRI). RESULTS: Postsurgery assessments revealed decreased aggression and agitation and improved quality of life. AB was correlated with testosterone levels and testosterone/cortisol ratio in males. No clinically significant side effects were observed. Imaging analyses showed preoperative amygdala volumes within normal populational range and confirmed lesion locations. The reductions in aggressive symptoms were accompanied by significant postsurgical volumetric reductions in brain areas classically associated with AB and increases in regions related to somatosensation. The local volumetric reductions are found in areas that in a normal brain show high expression levels of genes related to AB (eg, aminergic transmission) using gene expression data provided by the Allen brain atlas. CONCLUSION: These findings provide new insight into the whole brain neurocircuitry of aggression and suggest a role of altered somatosensation and possible novel neuromodulation targets.

Directional deep brain stimulation of the posteromedial hypothalamus for refractory intermittent explosive disorder: a case series using a novel neurostimulation device and intraoperative microdialysis

Intermittent Explosive Disorder (IED) is a psychiatric disorder characterized by recurrent outbursts of aggressive behaviour. Deep brain stimulation (DBS) in the posteromedial nucleus of the hypothalamus (pHyp) is an alternative therapy for extreme cases and shows promising results. Intraoperative microdialysis can help elucidate the neurobiological mechanism of pHyp-DBS. Objective To evaluate efficacy and safety of pHyp-DBS using eight-contact directional leads in patients with refractory IED (rIED) and the accompanying changes in neurotransmitters. Methods A prospective study in which patients with a diagnosis of rIED were treated with pHyp-DBS for symptom alleviation. Bilateral pHyp-DBS was performed with eight-contact directional electrodes. Follow-up was performed at 3, 6 and 12 months after surgery. Results Four patients (3 men, mean age 27 ± 2.8 yr) were included. All patients were diagnosed with rIED and severe intellectual disability. Two patients had congenital rubella, one has co-diagnosis of infantile autism and the fourth presents with drug-resistant epilepsy. There was a marked increase in the levels of GABA and glycine during intraoperative stimulation. The average improvement in aggressive behaviour in the last follow-up was 6 points (Δ: 50%, p= 0.003) while also documenting an important improvement of the SF-36 in all domains except bodily pain. No adverse events associated with pHyp-DBS were observed. Conclusions This is the first study to show the safety and beneficial effect of directional lead pHyp-DBS in patients with refractory Intermittent Explosive Disorder and to demonstrate the corresponding mechanism of action through increases in GABA and glycine concentration in the pHyp.

Concordância entre dois instrumentos para avaliação do letramento em saúde / Concordancia entre dos instrumentos para evaluación de la alfabetización en salud / Concordance between two instruments for health literacy assessment

Objetivo: Determinar a concordância entre os instrumentos de mensuração short test of functional health literacy in adults (S-TOFHLA) e short assessment of health literacy for Portuguese-speaking adults (SAHLPA-18) como estratégia para estimar a validade concorrente. Métodos: Estudo transversal, com usuários do Sistema Único de Saúde. Para testar a validade concorrente, aplicou-se abordagem de concordância com teste de Kappa ponderado para dados qualitativos. Resultados: Participaram 372 indivíduos, dos quais 66% e 62% não apresentaram nível de letramento adequado, segundo o SAHLPA-18 e o S-TOFHLA, respectivamente. Observou-se correlação forte entre os instrumentos (p<0,001; r=0,60); e a concordância de acertos encontrada, 65,3% (Kappa=0,35; p<0,001), foi considerada fraca. Conclusão: Os instrumentos SAHLPA-18 e S-TOFHLA apresentam constructos diferentes e fraca concordância. É indicado o uso de diferentes instrumentos em pesquisas de mensuração do nível de letramento; e desenvolvimento de instrumentos específicos às condições de saúde que permitam obter resultado próximo ao real contexto dos indivíduos.

Objetivo: Determinar la concordancia entre instrumentos de medición psicométrica short test of functional health literacy in adults (S-TOFHLA) y short assessment of health literacy for portuguese-speaking adults (SAHLPA-18) como estrategia para estimar la validez concurrente. Métodos: estudio transversal realizado con usuarios del Sistema Único de Salud. Para testear la validez concurrente se aplicó un enfoque de concordancia con una prueba ponderada de Kappa para datos cualitativos. Resultados: participaron 372 individuos. Se encontró que 66% y 62% de estos no tenía un nivel adecuado de letramiento según SAHLPA-18 y S-TOFHLA, respectivamente. Hubo una fuerte correlación entre los instrumentos (p<0.001; r=0.60), sin embargo 65.3% de concordancia, se consideró débil (Kappa=0.35; p<0.001). Conclusión: Los instrumentos SAHLPA-18 y S-TOFHLA tienen diferentes construcciones y escasa concordancia. En la investigación se indica el uso de diferentes instrumentos para medir el nivel de letramiento y el desarrollo de instrumentos específicos a las condiciones de salud que permitan obtener resultados cercanos al contexto real de los individuos.

Objetivo: To determine agreement between the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Short Assessment of Health Literacy for Portuguese-speaking Adults (SAHLPA-18) measurement instruments as a strategy for estimating concurrent validity. Methods: This was a cross-sectional study conducted with users of the Brazilian National Health System. An agreement approach using a weighted Kappa test for qualitative data was applied in order to test for concurrent validity. Results: 372 individuals participated. It was found that 66% and 62% of them did not have an adequate level of literacy according to SAHLPA-18 and S-TOFHLA, respectively. There was strong correlation between the instruments (p<0.001; r=0.60), although the 65.3% agreement of correct answers found was considered weak (Kappa=0.35; p<0.001). Conclusion: The SAHLPA-18 and S-TOFHLA instruments have different constructs and poor agreement. Use of different instruments is indicated in research intended to measure level of literacy, as is the development of instruments specific to health conditions that allow results close to the real context of individuals to be obtained.

Computer-assisted craniometric evaluation for diagnosis and follow-up of craniofacial asymmetries: SymMetric v. 1.0.

PURPOSE: The current assessment of patients with craniofacial asymmetries is accomplished by physical examination, anamnesis and radiological imaging. We propose a semi-automated, computer-assisted craniofacial evaluation (SymMetric v 1.0) based on orthogonal photography of the patient's head in 3 positions. The system is simple, low-cost, no-radiation or special resources needed. Although it does not substitute CT in cases of doubt between craniosynostosis and positional plagiocephaly, multiple numeric evaluations indicate regional deformities and severity of the asymmetry, which can help in the clinical decision of indicating or not the orthosis in positional deformities, determining treatment duration or evaluating surgical outcomes after correction. METHODS: A Matlab-based tool was developed for digital processing of photographs taken in 3 positions (anterior, superior and lateral). The software guides the user to select visible and reproducible landmarks in each photograph acquisition and calculates multiple indexes and metrics, generating a set of comprehensive plots to offer the user an overview of head and facial symmetry across the orthogonal views. For purposes of demonstration, we evaluated 2 patients (one control and one with non-sinostotic deformity). RESULTS: The results show a clear differentiation of the control and plagiocephalic patient metrics mainly in the superior view, showing potential for diagnosis of the condition, and also detected the clinical improvement during helmet treatment in the follow-up, 3 and 5 months after orthosis' use. CONCLUSION: We presented a proof-of-concept for a low cost, no radiation evaluation system for craniofacial asymmetries, that can be useful in a clinical context for diagnosis and follow-up of patients.

Deep brain stimulation in Tourette's syndrome: evidence to date.

Tourette's syndrome (TS) is a neurodevelopmental disorder that comprises vocal and motor tics associated with a high frequency of psychiatric comorbidities, which has an important impact on quality of life. The onset is mainly in childhood and the symptoms can either fade away or require pharmacological therapies associated with cognitive-behavior therapies. In rare cases, patients experience severe and disabling symptoms refractory to conventional treatments. In these cases, deep brain stimulation (DBS) can be considered as an interesting and effective option for symptomatic control. DBS has been studied in numerous trials as a therapy for movement disorders, and currently positive data supports that DBS is partially effective in reducing the motor and non-motor symptoms of TS. The average response, mostly from case series and prospective cohorts and only a few controlled studies, is around 40% improvement on tic severity scales. The ventromedial thalamus has been the preferred target, but more recently the globus pallidus internus has also gained some notoriety. The mechanism by which DBS is effective on tics and other symptoms in TS is not yet understood. As refractory TS is not common, even reference centers have difficulties in performing large controlled trials. However, studies that reproduce the current results in larger and multicenter randomized controlled trials to improve our knowledge so as to support the best target and stimulation settings are still lacking. This article will discuss the selection of the candidates, DBS targets and mechanisms on TS, and clinical evidence to date reviewing current literature about the use of DBS in the treatment of TS.

Amygdala and Hypothalamus: Historical Overview With Focus on Aggression.

Aggressiveness has a high prevalence in psychiatric patients and is a major health problem. Two brain areas involved in the neural network of aggressive behavior are the amygdala and the hypothalamus. While pharmacological treatments are effective in most patients, some do not properly respond to conventional therapies and are considered medically refractory. In this population, surgical procedures (ie, stereotactic lesions and deep brain stimulation) have been performed in an attempt to improve symptomatology and quality of life. Clinical results obtained after surgery are difficult to interpret, and the mechanisms responsible for postoperative reductions in aggressive behavior are unknown. We review the rationale and neurobiological characteristics that may help to explain why functional neurosurgery has been proposed to control aggressive behavior.

Training with brain-machine interfaces, visuo-tactile feedback and assisted locomotion improves sensorimotor, visceral, and psychological signs in chronic paraplegic patients.

Spinal cord injury (SCI) induces severe deficiencies in sensory-motor and autonomic functions and has a significant negative impact on patients' quality of life. There is currently no systematic rehabilitation technique assuring recovery of the neurological impairments caused by a complete SCI. Here, we report significant clinical improvement in a group of seven chronic SCI patients (six AIS A, one AIS B) following a 28-month, multi-step protocol that combined training with non-invasive brain-machine interfaces, visuo-tactile feedback and assisted locomotion. All patients recovered significant levels of nociceptive sensation below their original SCI (up to 16 dermatomes, average 11 dermatomes), voluntary motor functions (lower-limbs muscle contractions plus multi-joint movements) and partial sensory function for several modalities (proprioception, tactile, pressure, vibration). Patients also recovered partial intestinal, urinary and sexual functions. By the end of the protocol, all patients had their AIS classification upgraded (six from AIS A to C, one from B to C). These improvements translated into significant changes in the patients' quality of life as measured by standardized psychological instruments. Reexamination of one patient that discontinued the protocol after 12 months of training showed that the 16-month break resulted in neurological stagnation and no reclassification. We suggest that our neurorehabilitation protocol, based uniquely on non-invasive technology (therefore necessitating no surgical operation), can become a promising therapy for patients diagnosed with severe paraplegia (AIS A, B), even at the chronic phase of their lesion.

Assessment of Safety and Outcome of Lateral Hypothalamic Deep Brain Stimulation for Obesity in a Small Series of Patients With Prader-Willi Syndrome.

Importance: Deep brain stimulation (DBS) has been investigated for treatment of morbid obesity with variable results. Patients with Prader-Willi syndrome (PWS) present with obesity that is often difficult to treat. Objective: To test the safety and study the outcome of DBS in patients with PWS. Design, Setting, and Participants: This case series was conducted in the Hospital das Clínicas, University of São Paulo, Brazil. Four patients with genetically confirmed PWS presenting with severe obesity were included. Exposure: Deep brain stimulation electrodes were bilaterally implanted in the lateral hypothalamic area. After DBS implantation, the treatment included the following phases: titration (1-2 months), stimulation off (2 months), low-frequency DBS (40 Hz; 1 month), washout (15 days), high-frequency DBS (130 Hz; 1 month), and long-term follow-up (6 months). Main Outcomes and Measures: Primary outcome measures were adverse events recorded during stimulation and long-term DBS treatment. Secondary outcomes consisted of changes in anthropometric measures (weight, body mass index [calculated as weight in kilograms divided by height in meters squared], and abdominal and neck circumference), bioimpedanciometry, and calorimetry after 6 months of treatment compared with baseline. The following evaluations and measurements were conducted before and after DBS: clinical, neurological, psychiatric, neuropsychological, anthropometry, calorimetry, blood workup, hormonal levels, and sleep studies. Adverse effects were monitored during all follow-up visits. Results: Four patients with PWS were included (2 male and 2 female; ages 18-28 years). Baseline mean (SD) body mass index was 39.6 (11.1). Two patients had previous bariatric surgery, and all presented with psychiatric comorbidity, which was well controlled with the use of medications. At 6 months after long-term DBS, patients had a mean 9.6% increase in weight, 5.8% increase in body mass index, 8.4% increase in abdominal circumference, 4.2% increase in neck circumference, 5.3% increase in the percentage of body fat, and 0% change in calorimetry compared with baseline. Also unchanged were hormonal levels and results of blood workup, sleep studies, and neuropsychological evaluations. Two patients developed stimulation-induced manic symptoms. Discontinuation of DBS controlled this symptom in 1 patient. The other required adjustments in medication dosage. Two infections were documented, 1 associated with skin picking. Conclusions and Relevance: Safety of lateral hypothalamic area stimulation was in the range of that demonstrated in patients with similar psychiatric conditions receiving DBS. In the small cohort of patients with PWS treated in our study, DBS was largely ineffective.

The Retrograde Ventriculosinusal Shunt in an Animal Experimental Model of Hydrocephalus.

Currently, hydrocephalus treatment is performed mainly with ventriculoperitoneal shunting. This experimental study aims at assessing whether the experimental model of hydrocephalus in dogs is applicable to the laboratory study of the retrograde ventriculosinusal shunt (RVSS). Four mongrel dogs were assessed. After randomization, the animals were divided into two groups: an experimental group that underwent the induction of hydrocephalus/RVSS and a control group, for the measurement of the mean arterial pressure, intracranial pressure and pressure in the superior sagittal sinus (SSS). The controls presented a mean arterial pressure of 68 mm Hg (71 and 65), an intracranial pressure of 163 mm H2O (149.6 and 176.8) and a pressure at the SSS of 40 mm H2O (40 and 40). The kaolin injection into the cisterna magna at a concentration of 0.3 mg/ml was capable of inducing the clinical and radiological mechanism of hydrocephalus (intracranial pressure = 250 mm H2O, pressure at the SSS = 50 mm H2O). The caliber of the SSS was 2.5 ± 1.0 mm. The fact that the SSS caliber of the dog was the same size as the external diameter of the catheter used resulted in the complete obstruction of the SSS when the catheter was inserted. We believe we could design and perform an experimental model to test the RVSS. It is applicable and feasible. The model of hydrocephalus, the surgical apparatus and the scenario were adequate, but the shunt system needs to be proportionally made to the canine anatomy.

Optimizing microdialysis for deep brain stimulation.

Cerebral microdialysis is a chemical detection method capable of identifying and simultaneously sampling a wide range of substances in the micromilieu of the monitoring probe. The interstitial space of biological tissues and fluids is sampled through a thin fenestrated dialysis catheter inserted into the brain. The technique has been reported in patients with Parkinson's disease. However, the procedure is not widely used by neurosurgeons, possibly owing to unclear indications and poor effective benefits, mostly secondary to significant pitfalls. In spite of the feasibility of microdialysis in humans, many factors can affect the quality of the process. Possible pitfalls include improperly designed probe, probe insertion effects, ineffective perfusion rate, issues to optimize stabilization period, and insufficient volume sample. This article reviews those key technical features necessary for performing microdialysis in humans during deep brain stimulation for Parkinson's Disease.

Intraoperative dopamine release during globus pallidus internus stimulation in Parkinson's disease.

BACKGROUND: It is still unclear whether dopamine (DA) levels correlate with Parkinson's disease (PD) severity or play a role in the mechanisms of high-frequency stimulation (HFS). METHODS: We have used microdialysis to record pallidal DA in 5 patients with PD undergoing microelectrode-guided pallidotomy. RESULTS: We found that patients with more severe disease and, consequently, lower pallidal DA did poorly after pallidal lesions. In the operating room, 4 of 5 patients had a significant increase in DA levels during HFS (600%, on average). To test the hypothesis that DA was important for the effects of stimulation, we correlated the amelioration in rigidity observed in the operating room with pallidal DA release. Though rigidity was 56% better during stimulation, no correlation was found between such an improvement and DA release. CONCLUSIONS: These findings suggest that additional mechanisms not directly dependent on pallidal DA release may be involved in the clinical effects of HFS of the globus pallidus internus.

Bilateral subthalamic nucleus stimulation for generalized dystonia after bilateral pallidotomy.

BACKGROUND: Thalamotomies and pallidotomies were commonly performed before the deep brain stimulation (DBS) era. Although ablative procedures can lead to significant dystonia improvement, longer periods of analysis reveal disease progression and functional deterioration. Today, the same patients seek additional treatment possibilities. METHODS: Four patients with generalized dystonia who previously had undergone bilateral pallidotomy came to our service seeking additional treatment because of dystonic symptom progression. Bilateral subthalamic nucleus DBS (B-STN-DBS) was the treatment of choice. The patients were evaluated with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and the Unified Dystonia Rating Scale (UDRS) before and 2 years after surgery. RESULTS: All patients showed significant functional improvement, averaging 65.3% in BFMDRS (P = .014) and 69.2% in UDRS (P = .025). CONCLUSIONS: These results suggest that B-STN-DBS may be an interesting treatment option for generalized dystonia, even for patients who have already undergone bilateral pallidotomy.