Long-term follow-up of Huntington disease treated by bilateral deep brain stimulation of the internal globus pallidus

Deep brain stimulation is now accepted as a safe and efficient treatment for movement disorders including selected types of dystonia and dyskinesia. Very little, however, is known about its effect on other movement disorders, particularly for “choreic” movements. Huntington disease is a fatal autosomal-dominant neurodegenerative disorder characterized by movement disorders, progressive cognitive impairment, and psychiatric symptoms. Bilateral chronic stimulation of the internal globus pallidus was performed to control choreic movements in a 60-year-old man with a 10-year history of Huntington disease. Chronic deep brain stimulation resulted in remarkable improvement of choreic movements. Postoperative improvement was sustained after 4 years of follow-up with a marked improvement in daily quality of life.

Antero-ventral internal pallidum stimulation improves behavioral disorders in Lesch-Nyhan disease

The Lesch-Nyhan syndrome is an X-linked recessive disorder caused by a deficiency in hypoxanthine-guanine phosphoribosyl transferase, a purine salvage enzyme. Affected individuals exhibit a characteristic neurobehavioral disorder with delayed acquisition of motor skills, dystonia, severe self-mutilations, and aggressive behavior. Deep brain stimulation has been previously proposed for controlling isolated involuntary movements and psychiatric disorders. We applied a double bilateral simultaneous stimulation to limbic and motor internal pallidum in one patient for controlling both behavioral and movement disorders, respectively. The injurious compulsions disappeared; dystonia and dyskinesia were decreased at 28 months follow-up.

Chiari malformation and sleep related breathing disorders

OBJECTIVE

To estimate the frequency, mechanisms and predictive factors of sleep apnoea syndrome (SAS) in a large group of children and adults with type I (CMI) and II (CMII) Chiari malformation (CM).

BACKGROUND

The anatomical and functional integrity of both respiratory circuits and lower cranial nerves controlling the upper airway is necessary for breathing control during sleep. These latter structures may be altered in CM, and a few investigations have reported CM related sleep disordered breathing.

METHODS

Forty-six consecutive unrelated patients with CM (40 CMI, six CMII), of which 20 were children (eight males) and 26 were adults (12 males), underwent physical, neurological and oto-rhino-laryngoscopic examination, MRI and polysomnography.

RESULTS

SAS was present in 31 (67.4%) of the patients with CM (70% of CMI, 50% of CMII, including mainly children). Sixty per cent of children with CM exhibited SAS, including 35% with obstructive (OSAS) and 25% with central (CSAS) sleep apnoea syndrome. SAS was observed in 73% of CM adults (57.7% OSAS, 15.4% CSAS). Severe SAS was found in 23% of CM adults. Multiple regression analysis revealed that age, type II Chiari and vocal cord paralysis predicted the central apnoea index.

CONCLUSION

SAS is highly prevalent in all age groups of patients suffering from CM. CSAS, a rare condition in the general population, was common among the patients with CM in our study. Sleep disordered breathing associated with CM may explain the high frequency of respiratory failures observed during curative surgery of CM. Our results suggest that SAS should be systematically screened for in patients with CM, especially before surgery.

Dramatic weight loss with levetiracetam

BACKGROUND

Levetiracetam is considered a "weight-neutral" drug. We report 19 cases of significant weight loss associated with levetiracetam at a dose ranging from 500 to 2000 mg/day.

METHODS

The population was divided into two groups. Group 1 includes patients in whom levetiracetam was the only possible cause of weight loss and Group 2 those in whom other factors may have played a role. Similar cases reported by the French national drug safety center were added (Group 3).

RESULTS

Group 1 included 9 females and 3 males (weight loss ranging from 8.1% to 28.6%). Three patients had levetiracetam in monotherapy. Prior levetiracetam only three were overweight. One patient was hospitalized for a thorough assessment of weight loss. Seven patients reported reduced caloric intake due to decreased pleasure with food. The other five did not report any changes in feeding behavior. Group 2 included seven females with a weight loss ranging from 10% to 26.6%. One patient was on topiramate since two years prior to levetiracetam. Weight loss started with the introduction of levetiracetam. In 4 patients, there was a decreased dosage or cessation of a previous drug known to produce weight gain in some cases simultaneously to the introduction of levetiracetam, but in two of these patients these drugs had not produced any weight gain. Group 3 included only two patients (weight loss: 7 and 20 kg).

CONCLUSIONS

This study provides evidence that levetiracetam can cause significant weight loss. Women are at higher risk while initial weight is not a factor.

Angiogenesis is associated with blood-brain barrier permeability in temporal lobe epilepsy

Previous studies from our group, focusing on neuro-glial remodelling in human temporal lobe epilepsy (TLE), have shown the presence of immature vascular cells in various areas of the hippocampus. Here, we investigated angiogenic processes in hippocampi surgically removed from adult patients suffering from chronic intractable TLE, with various aetiologies. We compared hippocampi from TLE patients to hippocampi obtained after surgery or autopsy from non-epileptic patients (NE). We quantified the vascular density, checked for the expression of angiogenic factors and their receptors and looked for any blood-brain barrier (BBB) leakage. We used a relevant model of rat limbic epilepsy, induced by lithium-pilocarpine treatment, to understand the sequence of events. In humans, the vessel density was significantly higher in TLE than in NE patients. This was neither dependent on the aetiology nor on the degree of neuronal loss, but was positively correlated with seizure frequency. In the whole hippocampus, we observed many complex, tortuous microvessels. In the dentate gyrus, when the granular layer was dispersed, long microvessels appeared radially orientated. Vascular endothelial factor (VEGF) and tyrosine kinase receptors were detected in different types of cells. An impairment of the BBB was demonstrated by the loss of tight junctions and by Immunoglobulines G (IgG) leakage and accumulation in neurons. In the rat model of TLE, VEGF over-expression and BBB impairment occurred early after status epilepticus, followed by a progressive increase in vascularization. In humans and rodents, angiogenic processes and BBB disruption were still obvious in the chronic focus, probably activated by recurrent seizures. We suggest that the persistent leakage of serum IgG in the interstitial space and their uptake by neurons may participate in hypoperfusion and in neuronal dysfunction occurring in TLE.

Video-EEG in syncopal attack due to ocular compression in an adolescent mistreated for epilepsy

Vasovagal syncope can be confused with epileptic seizure. In this situation, eye compression may be performed during EEG. We present a video-EEG of a patient in whom eye compression produced a typical syncope. Before this recording, the patient had been treated for five years with sodium valproate because of a misdiagnosis of epilepsy. The diagnosis of neurally-mediated syncope was not difficult on the basis of the clinical history, but the reproduction of syncope reinforced the correct diagnosis. Ocular compression is now only indicated in exceptional circumstances and should be performed with precautions. The video of this episode in an adolescent should be of considerable educational value to those who are confronted to diagnostic work-up of transient loss of consciousness.

Neurodegeneration with brain iron accumulation: clinical, radiographic and genetic heterogeneity and corresponding therapeutic options

BACKGROUND

Neurodegeneration with brain iron accumulation (NBIA), formerly known as Hallervorden-Spatz syndrome, is a heterogeneous group of disorders with different treatment options.

CASE REPORTS

In the first case, progressively generalizing dystonic symptoms appeared during childhood. A mutation in the gene encoding pantothenate kinase 2 (PANK2) was found. Brain MRI showed bilateral hypersignals within the globus pallidi on T2-weighted images. The patient was successfully treated by pallidal deep brain stimulation (DBS). In the second case an adult onset with parkinsonism was observed, for which no PANK2 mutation was found. T2-weighted brain MR images revealed multiple significant hyposignals (suggestive of iron deposits) localised in the cerebellar dentate nuclei and in the globi pallidi, the red nuclei and the substantia nigra. An antiparkinsonian treatment was proposed.

CONCLUSION

The clinical, radiographic and genetic heterogeneity of NBIA has to be underlined.

[Neurosurgical treatment in childhood dystonias and dyskinesias]

AIM

To present the post-surgery clinical results of deep brain stimulation of the internal globus pallidus (GPi) in a group of paediatric patients with primary and secondary dystonic-dyskinetic syndrome.

PATIENTS AND METHODS

Between November 1996 and May 2006, 121 patients were submitted to interventions with bilateral deep brain stimulation of the GPi, 58 of whom were children (age range: 5-16 years); 35 were cases of primary dystonia, of which 17 were carriers of the DYT1 mutation and 10 were not. A further 8 cases were myoclonic dystonias, 3 of whom presented the DYT11 mutation. With regard to the secondary dystonias, 4 were carriers of PKAN (pantothenate kinase-associated neurodegeneration) syndrome and 9 were cases of post-anoxic encephalopathies.

RESULTS

Percentage improvements were as follows: in the case of DYT1+ primary dystonias, 80% at one year maintained at 3 years; in cases of DYT1-, 70% at one year maintained at 3 years, and in the myoclonic dystonias, 50% at one year and 85% at 3 years. In the group of patients with secondary dystonias due to post-anoxic encephalopathies, we found an improvement of 30% at one year and 40% at 3 years; in the group with PKAN syndrome, the figures were 60% at one year and 50% at two years.

CONCLUSIONS

Treatment involving bilateral deep brain stimulation of the GPi nuclei in childhood cases of generalised dystonias is highly effective, the best prognoses being those offered by the group with primary dystonias and especially those related to the DYT1 mutation. Treatment also proved to be effective in the case of secondary dystonias, although with lower degrees of improvement.

Correlation of preoperative thallium SPECT with histological grading and overall survival in adult gliomas

BACKGROUND

The management and prognosis of a glioma depend on the tumour's histological grade. Thus, preoperative prediction of the grade is routinely needed to indicate whether surgery or biopsies are required. It has been proposed that thallium single photon emission computed tomography (SPECT), in a relative short series, will aid this prediction.

AIM

To confirm the correlation between the results of preoperative thallium SPECT and grade of tumour as well as patient survival, and to define the cut-off value of the optimal thallium index for the detection of high grade gliomas in a large series of patients.

METHODS

One hundred and eighteen patients treated for glioma were retrospectively included in this study. All patients underwent preoperative 201Tl SPECT upon initial presentation and were referred for neurosurgery. Initial scintigraphic findings were correlated with the histological grade of the tumour and overall patient survival.

RESULTS

Thallium uptake was highly correlated with histological grade; the mean thallium indices for low grade and high grade gliomas were 1.8 and 4.9, respectively. On the basis of receiver operating characteristic analysis, the optimal cut-off value of the thallium index for the detection of high grade glioma was determined. By using 2.2 as the value for the threshold thallium index, the sensitivity and specificity were 93% and 72%, respectively. Kaplan-Meier estimates of the overall survival curves, as a function of the thallium index, indicated that it was correlated with the overall survival (P<0.001).

CONCLUSION

Thallium SPECT provides useful information about the histological grade of the tumour and overall patient survival. Additionally, in spite of its relatively weak resolution, it appears to be a powerful routine clinical tool for the management of gliomas.

The diverse phenotype and genotype of pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal-recessive disorder caused by mutations in the PANK2 gene. The authors report clinical and genetic findings of 16 patients with PKAN. The authors identified 12 mutations in the PANK2 gene, five of which were new. Only nine patients could be classified as classic or atypical PKAN, and intermediate phenotypes are described. Two patients presented with motor tics and obsessive-compulsive behavior suggestive of Tourette syndrome.

[Acutely ruptured intracranial aneurysms treated with GDC coils. Results from a single center over a period of 5 years]

PURPOSE

We prospectively reviewed the clinical results of acutely ruptured cerebral aneurysms treated with GDC over a 5 year period, in order to characterize death and dependency factors.

METHODS

Between 1997 and 2002, 229 patients (254 aneurysms treated, 140 females, 89 males; mean age: 51 years) with aneurysmal subarachnoid hemorrhage were treated with GDC (Boston Scientific Neurovascular, Fremont, CA) once the anatomical conditions of feasibility had been achieved. Over 90% of the aneurysms treated (mean size: 5,8 mm) were located in the anterior circulation. The anterior communicating artery complex (87 cases), the posterior aspect of the internal carotid artery (65 cases), and the middle cerebral artery (49 cases) were most commonly treated.

RESULTS

At the end of the initial hospitalization period, 14 patients (6.1%) died. Major procedural complications were associated with perforation of the aneurysmal sac in 9 patients (3.9%), thromboembolic events in 10 patients (4.3%) which resulted in 2 deaths (0.8%) and permanent neurologic morbidity in 7 patients (3%). The univariate analysis demonstrated no correlation between death and time-to-treatment, the topography of the aneurysm, or the occurrence of treatment related complications. The results of the logistical regression model demonstrated that the clinical score upon entry, and the occurrence of delayed ischemia were the only independent factors correlated with patient death. The prognostic factors affecting the degree of sequellae identified by the logistical regression model were the clinical score upon admission, age, treatment related complications, and pulmonary complications.

CONCLUSIONS

Endovascular treatment of ruptured anterior circulation aneurysms with GDC, including MCA aneurysms, is associated with low morbidity and allows good overall outcomes in patients with subarachnoid hemorrhage. A better understanding of dependency factors associated with endovascular coiling will foster further technical advances in order to improve the treatment of small and medium sized ruptured aneurysms.

Deep brain stimulation in movement disorders: stereotactic coregistration of two-dimensional electrical field modeling and magnetic resonance imaging

Object. Adjusting electrical parameters used in deep brain stimulation (DBS) for dystonia remains time consuming and is currently based on clinical observation alone. The goal of this study was to visualize electrical parameters around the electrode, to correlate these parameters with the anatomy of the globus pallidus internus (GPI), and to study the relationship between the volume of stimulated tissue and the electrical parameter settings.

Methods. The authors developed a computer-assisted methodological model for visualizing electrical parameters (the isopotential and the isoelectric field magnitude), with reference to the stereotactic target, for different stimulation settings (monopolar and bipolar) applied during DBS. Electrical field values were correlated with the anatomy of the GPI, which was determined by performing stereotactic magnetic resonance imaging in one reference patient.

By using this method it is possible to compare potential and electrical field distributions for different stimulation modes. In monopolar and bipolar stimulation, the shape and distribution of the potential and electrical field are different and depend on the stimulation voltage. Distributions visualized for patient-specific parameters can be subsequently correlated with anatomical information. The application of this method to one patient demonstrated that the 0.2-V/mm isofield line fits best with the lateral GPI borders at the level of the stimulated contacts.

Conclusions. The electrical field is a crucial parameter because it is assumed to be responsible for triggering action potentials. Electrical field visualization allows the calculation of the stimulated volume for a given isoline. Its application to an entire series of patients may help determine a threshold for obtaining a therapeutic effect, which is currently unknown, and consequently may aid in optimizing parameter settings in individual patients.

Electrophysiological characteristics of limbic and motor globus pallidus internus (GPI) neurons in two cases of Lesch–Nyhan syndrome

OBJECTIVE

Lesch-Nyhan syndrome is a rare and debilitating condition characterized by dystonia and self-mutilating behavior. In order to shed light on the pathophysiology of dystonia, we report the pallidal electrophysiological activity recorded in two patients during deep brain stimulation surgery (DBS).

METHODS

Microrecordings were performed on 162 neurons along four tracks aimed at the right and left anterior (limbic) and posterior (motor) globus pallidus internus (GPI).

RESULTS

Regardless of the anesthetic agent used (propofol or sevoflurane), both patients showed similar neurons firing rates in the four regions studied, namely the limbic and motor portions of the globus pallidus externus (GPE) or GPI. In both patients, firing rates were similar in the GPE (12.2+/-1.8 Hz, N=38) and GPI (13.2+/-1.0 Hz, N=83) portions of the limbic track, while the motor GPE fired at a higher frequency (23.8+/-2.7 Hz, N=18) than the motor GPI (12.5+/-1.4 Hz, N=23).

CONCLUSIONS

These results demonstrate that light propofol or sevoflurane anesthesia influences pallidal activity in a similar way. Electrophysiological recordings suggest that Lesch-Nyhan syndrome might be characterized by analogous firing frequencies in the limbic GPE and GPI while motor GPE would tend to fire at higher rate than the motor GPI. It is therefore tempting to suggest that the symptoms that are observed in Lesch-Nyhan syndrome might result from motor GPI inhibition.

SIGNIFICANCE

This observation may confirm the Albin and Delong's model of the basal nuclei in hypokinetic and hyperkinetic disorders.

Co-registration of stereotactic MRI and isofieldlines during deep brain stimulation

OBJECT

The parameter adjustment process during deep brain stimulation (DBS) for dystonia remains time consuming and based on clinical observation alone. The aim was to correlate the electric field with the GPi anatomy to be able to study the stimulated volume.

METHODS

We developed a computer-assisted method (model) for visualizing electric field in reference to the stereotactic space. Electric field values were correlated with the GPi anatomy (stereotactic Magnetic Resonance Imaging) in one reference patient.

RESULTS

Using this methodology it becomes possible to correlate the electric field distributions for patient specific parameters with the anatomical information. The application to one patient showed that the 0.1V/mm isofieldline fits best with the lateral GPi borders at the level of the stimulated contacts.

CONCLUSIONS

The electric field is a crucial parameter as it is assumed to be responsible for triggering action potentials. Electric field visualisation allows the calculation of the stimulated volume for a given isoline. Its application to our whole patient population might help in determining a threshold for obtaining a therapeutic effect, to date unknown, and consequently in optimizing the parameter setting in each patient.

Lamotrigine associated with exacerbation or de novo myoclonus in idiopathic generalized epilepsies

Five patients with idiopathic generalized epilepsies (IGE) treated with lamotrigine (LTG) experienced exacerbation or de novo appearance of myoclonic jerks (MJ). In three patients, LTG exacerbated MJ in a dose-dependent manner with early aggravation during titration. MJ disappeared when LTG dose was decreased by 25 to 50%. In two patients, LTG exacerbated MJ in a delayed but more severe manner, with myoclonic status that only ceased after LTG withdrawal.

Increased number of neural progenitors in human temporal lobe epilepsy

An increased neurogenesis is reported in animal models of mesial temporal lobe epilepsy (MTLE) but the fate of newborn cells is unknown. Here, we attempted to demonstrate neurogenesis in adult epileptic tissue obtained after hippocampectomy. MTLE hippocampi showed increased expression of division markers and of Musashi-1, a marker of neural progenitors, compared to control hippocampi. Large quantities of Musashi-1+ cells were obvious in the subgranular layer and the subventricular zone, both known neurogenic areas, and in the fissura hippocampi. Musashi-1 was expressed by small cells that were mainly vimentin+ or nestin+, rarely Dcx+ or PSA-NCAM+ and negative for markers of mature neurons or astrocytes. Some of them are present in the granular layer, the hilus, and CA1 area resembling the ectopic positions described in rodents. These findings demonstrate that neural progenitors proliferate in chronic epilepsy and suggest that the fissura hippocampi behaves like another neurogenic area.

Stereotactic coregistration of 201Tl SPECT and MRI applied to brain tumor biopsies

The aim of the present study was to determine the clinical feasibility of integration of stereotactic SPECT (sSPECT) with 201Tl in the stereotactic MRI (sMRI)-based planning of brain tumor biopsy. Furthermore, the predictive value of the integrated techniques was analyzed by comparison with the corresponding histologically determined metabolic activity.

METHODS

Ten patients underwent combined 201Tl SPECT- and MRI-guided stereotactic biopsy of intracranial lesions according to a previously described technique. An area of abnormal 201Tl uptake was used to guide the stereotactic biopsy trajectory. Several samples were taken along the trajectory above and beneath the target. An extensive histologic diagnosis (tumor grade, mitotic index [MI], and Ki67 index) and the 201Tl index were obtained for all samples and compared statistically.

RESULTS

Combined 201Tl sSPECT- and sMRI-guided biopsy could be performed on all patients. Ki67 index, MI, and tumor grade correlated significantly. The correlations between MI or Ki67 index and 201Tl index were not significant (0.18 and 0.09, respectively). A trend to significance existed between tumor grade and 201Tl index (R = 0.31; P = 0.06). Mean 201Tl index for grade III tumors (3.27 +/- 1.89 [SD]) was significantly different from that for grade IV tumors (4.34 +/- 1.29). The sample position on the trajectory correlated with the MI (R = 0.39; P = 0.01). In 4 of the 10 patients, a variation in tumor grade could be observed along the trajectory. In all patients, the highest proliferative activity was within 5-10 mm of the target.

CONCLUSION

These results support the view that 201Tl SPECT may contribute to the successful management of brain tumor patients requiring stereotactic biopsy, without causing a significant increase in discomfort or morbidity. The development of similar techniques integrating sSPECT data in the planning of stereotactic biopsy should be considered by centers performing stereotactic surgery and having access to SPECT technology. In the long term, this technique could become a support for focused gene therapy and cell transfer.

Pallidal stimulation improves pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) causes a progressive generalized dystonia which remains pharmacologically intractable. We performed bilateral internal globus pallidus stimulation in six patients with genetically confirmed PKAN who obtained a major and long-lasting improvement of their painful spasms, dystonia, and functional autonomy. This study shows the benefits of pallidal DBS for the dystonia of PKAN patients.