G. Squintani

Treatment of essential tremor: A systematic review of evidence and recommendations from the Italian Movement Disorders Association

Essential tremor (ET) is one of the most common movement disorders of adults, characterized by postural and kinetic tremor. It often causes embarrassment and more rarely serious disability, requiring treatment. To assess the current state of knowledge on ET therapy and produce recommendations based on the analysis of evidence the authors reviewed the literature regarding pharmacologic and surgical therapies, providing a quality assessment of the studies and the strength of recommendations for each treatment. A committee of experts selected clinical-based questions to guide the search. A systematic literature review was performed to identify all the studies conducted on patients with ET published until September 2010. Articles were classified according to GRADE evidence profile, a system for grading the quality of evidence and the strength of recommendation based on the quality of the studies. The quality of evidence was often rated as “low” or “very low” for the studies analyzed. Propranolol, long-acting propranolol, primidone, and topiramate are recommended as first-line therapy, with restrictions for their side effects. Arotinolol, sotalol, ICI 118.551 and LI 32.468 (experimental drugs), zonisamide, gabapentin, alprazolam, clozapine, and olanzapine are recommended as a second-line treatment. Botulinum toxin type A and thalamic deep-brain stimulation are recommended for refractory ET. The results highlight the need of well-designed direct comparison trials aimed at evaluating relative effectiveness and safety of the drugs currently used in clinical practice. Furthermore, additional controlled clinical trials are required to define other possible treatment strategies for ameliorating the management of ET.

Abnormal tactile temporal discrimination in psychogenic dystonia

Objective: Neurophysiologic studies demonstrated that patients with primary torsion dystonia (PTD) and with psychogenic dystonia (Psy-D) share similar abnormalities in the motor system. In this study, we evaluated somatosensory function in Psy-D by testing temporal discrimination threshold (TDT), and compared the results with those obtained in patients with PTD. Methods: TDT of tactile stimuli was assessed in 10 patients with Psy-D, 10 patients with PTD, and 16 control subjects. The 2 groups of patients were matched for age, gender, disease duration, and distribution of dystonia. Tactile stimuli consisted of pairs of non-noxious electrical shocks delivered to the right or left hand at interstimulus interval increasing from 0 to 400 msec, in 10-msec steps. TDT was defined as the value at which subjects recognized the 2 stimuli as asynchronous. Results: TDT was higher in Psy-D and PTD compared to control subjects, for both the right and the left hand. In a subgroup of patients with unilateral dystonia (Psy-D = 4, PTD = 5), TDT did not differ between the affected and the unaffected side in both groups of patients. Disease duration was not correlated to the increased TDT value. Conclusions: Our study suggests an impaired processing of somatosensory inputs in both Psy-D and PTD. These abnormalities might represent a neurophysiological trait predisposing to develop a dystonic posture triggered by psychiatric and psychological factors.

A novel mutation of aprataxin associated with ataxia ocular apraxia type 1: phenotypical and genotypical characterization.

Ataxia oculomotor apraxia type 1 (AOA1) is the most common form of autosomal recessive ataxia in Japan, and the second in Portugal after Friedreich ataxia. AOA1 is typically characterized by early-onset cerebellar ataxia, oculomotor apraxia, hypoalbuminemia, hypercholesterolemia and late axonal sensori-motor neuropathy. AOA1 is associated with the aprataxin gene (APTX) encoding a protein involved in DNA repair. We characterized a novel homozygous missense mutation of APTX in a 34 year-old female patient born from consanguineous parents. The mutation, a Val230Gly caused by a c.689 T>G substitution, involved the histidine-triad (HIT) domain of the protein, affected a phylogenetically conserved amino acid and was absent in the control population. We described the clinical and neurophysiological features, the findings at structural and functional brain imaging, and the pathological picture of the sural nerve biopsy. The report emphasized the genetical and phenotypical heterogeneity of AOA1 by demonstrating atypical features such as absence of oculomotor apraxia and signs of pyramidal involvement. Expression studies by Western blotting on fibroblasts demonstrated that the homozygous Val230Gly mutation was associated with decreased levels of APTX indicating a loss-of-function mechanism.

Progressive multifocal leukoencephalopathy in a patient with Good's syndrome

Goods syndrome (GS) is an immunodeficiency characterized by thymoma, hypogammaglobulinemia, and impaired T-cell function. The clinical manifestations of GS include recurrent or chronic infections from common or opportunistic pathogens. Encephalitis is a rare event, with only anecdotal reports of cytomegalovirus infection. Herein we report the case of a 79-year-old woman with GS who developed subacute motor deficits and cognitive changes. Magnetic resonance imaging (MRI) of the brain disclosed white- and gray-matter lesions, mostly in the right frontal and parietal areas. Polyoma virus JC, the agent of progressive multifocal encephalopathy (PML), was identified in cerebrospinal fluid samples and brain biopsy specimens. After diagnosis, the disease had a rapid fatal course. The present case represents the first reported association between GS and PML.

Intraoperative neurophysiological monitoring during surgery for Chiari malformations

Reports on the use of intraoperative neurophysiological monitoring (INM) techniques during surgery for Chiari malformations are anecdotal. There are almost no data on significant intraoperative worsening in either somatosensory-evoked potentials (SEPs) or brainstem auditory-evoked potentials (BAEPs) during surgery that would have alerted the surgeon to modify the surgical strategy. Yet, a few reports suggest that INM may play a role in preventing spinal cord injury during positioning of the patient. Overall, the use of INM in this type of surgery can be considered only as an option. More speculatively, INM adds information to the ongoing discussion on the most appropriate surgical technique for posterior fossa decompression in Chiari malformations. This debate applies especially to children where a more conservative approach is advisable to reduce the complications. Studies on the conduction time of BAEPs provide some evidence that, from a merely neurophysiological perspective, most of the improvement occurs after bony decompression and removal of the dural band at the level of the atlanto-occipital membrane, not after duraplasty.

Awake surgery between art and science. Part I: clinical and operative settings

Awake surgery requires coordinated teamwork and communication between the surgeon and the anesthesiologist, as he monitors the patient, the neuroradiologist as he interprets the images for intraoperative confirmation, and the neuropsychologist and neurophysiologist as they evaluate in real-time the patients responses to commands and questions. To improve comparison across published studies on clinical assessment and operative settings in awake surgery, we reviewed the literature, focusing on methodological differences and aims. In complex, interdisciplinary medical care, such differences can affect the outcome and the cost-benefit ratio of the treatment. Standardization of intraoperative mapping and related controversies will be discussed in Part II.

Efficacy of pregabalin in a case of stiff-person syndrome: Clinical and neurophysiological evidence

Symptomatic treatment of stiff-person syndrome (SPS) might be challenging and a significant improvement of stiffness and rigidity is generally reached with high doses of benzodiazepines or baclofen causing side effects. A 71-year old woman diagnosed with SPS complained of marked stiffness of trunk and lower limb muscles with sudden painful spasms. She was unable to walk and she could not lean on her right leg. Cortical silent period (CSP) duration evaluated from right abductor pollicis brevis (APB) with transcranial magnetic stimulation was shortened. Polygraphic electromyographic (EMG) evaluation from paraspinal and leg muscles disclosed continuous motor unit activity at rest with interference muscular pattern. Symptomatic treatment with diazepam was withdrawn because of excessive sedation. In order to relieve the intense lumbar pain, she was prescribed pregabalin; since the day after, rigidity and painful spasms dramatically improved and she could walk without assistance. The clinical benefit persisted at 3 months follow-up and was paralleled by almost complete disappearance of EMG activity at rest and prolongation of CSP. The clinical and electrophysiological data in this SPS patient suggest the possible efficacy of pregabalin as symptomatic treatment without any significant side effects, which needs to be replicated in larger case series.

Intraoperative cortical mapping of visuospatial functions in parietal low-grade tumors: changing perspectives of neurophysiological mapping

OBJECT The aim of this study was to explore the feasibility of intraoperative visuospatial mapping with the same criteria currently used to define essential language areas. METHODS The authors compared surgical procedures in 2 patients with similar tumors (Grade II oligodendroglioma in the right parietal lobe) undergoing awake, image-assisted surgery for lesion removal with intraoperative neurophysiological monitoring. The line bisection task was used in both patients but with different criteria. RESULTS In the first case, the authors respected any area, even within the tumor, where significant interference was found (a stimulation-induced error in 2 of 3 applications defined an essential area). In the second case, they removed 1 essential area located in the tumor and recorded an uneventful clinical response soon thereafter. They continued to monitor the patient without stimulation and stopped the resection when the patient was close to the criteria valid for defining spatial neglect. The signs of spatial neglect were present for 3 days postoperatively and then cleared spontaneously. Subtotal tumor removal was achieved in both cases. CONCLUSIONS Evidence in the present study reveals that areas for visuospatial functions cannot be assessed with the same criteria used for language functions, since essential areas located in the tumor can be safely removed.

Intra-operative neurophysiological mapping and monitoring during brain tumour surgery in children: an update

IntroductionOver the past decade, the reluctance to operate in eloquent brain areas has been reconsidered in the light of the advent of new peri-operative functional neuroimaging techniques and new evidence from neuro-oncology. To maximise tumour resection while minimising morbidity should be the goal of brain surgery in children as much as it is in adults, and preservation of brain functions is critical in the light of the increased survival and the expectations in terms of quality of life.DiscussionIntra-operative neurophysiology is the gold standard to localise and preserve brain functions during surgery and is increasingly used in paediatric neurosurgery. Yet, the developing nervous system has peculiar characteristics in terms of anatomical and physiological maturation, and some technical aspects need to be tailored for its use in children, especially in infants. This paper will review the most recent advances in the field of intra-operative neurophysiology (ION) techniques during brain surgery, focussing on those aspects that are relevant to the paediatric neurosurgery practice.

Unusual Parsonage-Turner syndrome with relapses and bilateral simultaneous anterior interosseous neuropathy.

We report an unusual case of Parsonage–Turner syndrome with relapses and simultaneous bilateral anterior interosseous neuropathy (AIN). A 66-year-old man, after a typical right brachial amyotrophic neuralgia few months previously, underwent surgery for left carpal tunnel syndrome. The day following surgery, wrist aching and bilateral weakness, even if prevalent on the right side, on thumb and index finger flexion appeared. Neurophysiology was consistent with bilateral AIN neuropathy and serology revealed anti-nucleus antibody positivity. Association of relapses with bilateral acute AIN involvement in the subject with autoantibody detection can suggest an immunological pathogenesis.