Evangelia Liouta

Transcranial Direct Current Stimulation Effects in Disorders of Consciousness

OBJECTIVEnTo assess the efficacy of transcranial direct current stimulation (tDCS) on improving consciousness in patients with persistent unresponsive wakefulness syndrome (UWS) (previously termed persistent vegetative state [PVS]) or in a minimally conscious state (MCS).nnnDESIGNnProspective, case series trial with follow-up at 12 months.nnnSETTINGnGeneral and research hospital.nnnPARTICIPANTSnInpatients in a PVS/UWS or MCS (N=10; 7 men, 3 women; age range, 19-62y; etiology: traumatic brain injury, n=5; anoxia, n=4; postoperative infarct, n=1; duration of PVS/UWS or MCS range, 6mo-10y). No participant withdrew because of adverse effects.nnnINTERVENTIONnAll patients received sham tDCS for 20 minutes per day, 5 days per week, for 1 week, and real tDCS for 20 minutes per day, 5 days per week, for 2 weeks. An anodal electrode was placed over the left primary sensorimotor cortex or the left dorsolateral prefrontal cortex, with cathodal stimulation over the right eyebrow. One patient in an MCS received a second round of 10 tDCS sessions 3 months after initial participation.nnnMAIN OUTCOME MEASUREnJFK Coma Recovery Scale-Revised.nnnRESULTSnAll patients in an MCS showed clinical improvement immediately after treatment. The patient who received a second round of tDCS 3 months after initial participation showed further improvement and emergence into consciousness after stimulation, with no change between treatments. One patient who was in an MCS for <1 year before treatment (postoperative infarct) showed further improvement and emergence into consciousness at 12-month follow-up. No patient showed improvement before stimulation. No patient in a PVS/UWS showed immediate improvement after stimulation, but 1 patient who was in a PVS/UWS for 6 years before treatment showed improvement and change of status to an MCS at 12-month follow-up.nnnCONCLUSIONSntDCS seems promising for the rehabilitation of patients with severe disorders of consciousness. Severity and duration of pathology may be related to the degree of tDCS beneficial effects.

Transcranial alternating current stimulation reduces symptoms in intractable idiopathic cervical dystonia: a case study.

Idiopathic cervical dystonia (ICD) is a movement disorder often resulting in profound disability and pain. Treatment options include oral medications or other invasive procedures, whereas intractable ICD has been shown to respond to invasive (deep) brain stimulation. In the present blinded, placebo-controlled case study, transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) has been applied to a 54-year old patient with intractable ICD. Results showed that 15 Hz tACS had both immediate and cumulative effects in dystonic symptom reduction, with a 54% reduction in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score, and a 75% in the TWSTRS Pain Scale. These effects were persistent at 30-days follow-up. This is the first report to demonstrate a significant and lasting therapeutic effect of non-invasive electrical brain stimulation in dystonia.

Effects of intracranial meningioma location, size, and surgery on neurocognitive functions: a 3-year prospective study.

OBJECT Current recommendations stress the need for cognitive parameters to be integrated in the evaluation of outcomes for intracranial meningioma surgery. The aim of this prospective study was to examine neurocognitive function in meningioma patients pre- and postoperatively. METHODS Patients with skull base (anterior and middle fossa) and convexity (anterior and posterior) meningiomas (n = 54) underwent neuropsychological examination prior to and 1 year after surgery. A control group (n = 52) of healthy volunteers matched for age, sex, and education underwent the same examination. Assessments included executive, memory, and motor functions with standardized testing. Patients with convexity meningiomas were clinically assessed for parietal association cortex functions. RESULTS All patients performed significantly worse (p < 0.05) in most neurocognitive domains than controls. The skull base group showed more disturbances in memory than the convexity group (p < 0.05). The anterior convexity group showed more deficits in executive function than the posterior convexity group, which presented with parietal association cortex deficits. Verbal deficits were more pronounced in the left hemisphere than in the right hemisphere. Patients with a large tumor (> 4 cm) had more severe neurocognitive deficits than those with a small tumor (< 4 cm). Postoperatively, patients showed no deterioration in neurocognitive function. Instead, significant improvement (p < 0.05) was observed in some executive, motor, and parietal association cortex functions. CONCLUSIONS According to the authors findings, intracranial meningiomas may cause neurocognitive deficits in patients. Surgery does not cause a deterioration in cognitive function; instead, it may lead to improvements in some functions. Permanent neuropsychological postoperative deficits should be interpreted as tumor-induced rather than due to surgery.

Prognostic value of preoperative dynamic contrast-enhanced MRI perfusion parameters for high-grade glioma patients

IntroductionThe prognostic value of the dynamic contrast-enhanced (DCE) MRI perfusion and its histogram analysis-derived metrics is not well established for high-grade glioma (HGG) patients. The aim of this prospective study was to investigate DCE perfusion transfer coefficient (Ktrans), vascular plasma volume fraction (vp), extracellular volume fraction (ve), reverse transfer constant (kep), and initial area under gadolinium concentration time curve (IAUGC) as predictors of progression-free (PFS) and overall survival (OS) in HGG patients.MethodsSixty-nine patients with suspected anaplastic astrocytoma or glioblastoma underwent preoperative DCE-MRI scans. DCE perfusion whole tumor region histogram parameters, clinical details, and PFS and OS data were obtained. Univariate, multivariate, and Kaplan–Meier survival analyses were conducted. Receiver operating characteristic (ROC) curve analysis was employed to identify perfusion parameters with the best differentiation performance.ResultsOn univariate analysis, ve and skewness of vp had significant negative impacts, while kep had significant positive impact on OS (Pxa0<xa00.05). ve was also a negative predictor of PFS (Pxa0<xa00.05). Patients with lower ve and IAUGC had longer median PFS and OS on Kaplan–Meier analysis (Pxa0<xa00.05). Ktrans and ve could also differentiate grade III from IV gliomas (area under the curve 0.819 and 0.791, respectively).ConclusionsHigh ve is a consistent predictor of worse PFS and OS in HGG glioma patients. vp skewness and kep are also predictive for OS. Ktrans and ve demonstrated the best diagnostic performance for differentiating grade III from IV gliomas.

The cerebral isthmus: fiber tract anatomy, functional significance, and surgical considerations.

OBJECTIVEnThe cerebral isthmus is the white matter area located between the periinsular sulcus and the lateral ventricle. Studies demonstrating the fiber tract and topographic anatomy of this entity are lacking in current neurosurgical literature. Hence, the authors primary aim was to describe the microsurgical white matter anatomy of the cerebral isthmus by using the fiber dissection technique, and they discuss its functional significance. In addition, they sought to investigate its possible surgical utility in approaching lesions located in or adjacent to the lateral ventricle.nnnMETHODSnThis study was divided into 2 parts and included 30 formalin-fixed cerebral hemispheres, 5 of which were injected with colored silicone. In the first part, 15 uncolored specimens underwent the Klingers procedure and were dissected in a lateromedial direction at the level of the superior, inferior, and anterior isthmuses, and 10 were used for coronal and axial cuts. In the second part, the injected specimens were used to investigate the surgical significance of the superior isthmus in accessing the frontal horn of the lateral ventricle.nnnRESULTSnThe microsurgical anatomy of the anterior, superior, and inferior cerebral isthmuses was carefully studied and recorded both in terms of topographic and fiber tract anatomy. In addition, the potential role of the proximal part of the superior isthmus as an alternative safe surgical corridor to the anterior part of the lateral ventricle was investigated.nnnCONCLUSIONSnUsing the fiber dissection technique along with coronal and axial cuts in cadaveric brain specimens remains a cornerstone in the acquisition of thorough anatomical knowledge of narrow white matter areas such as the cerebral isthmus. The surgical significance of the superior isthmus in approaching the frontal horn of the lateral ventricle is stressed, but further studies must be carried out to elucidate its role in ventricular surgery.

Transcranial Electrical Stimulation: Methodology and Applications

Low-intensity transcranial current stimulation is a rapidly growing field of research. Transcranial direct current stimulation (tDCS) is the dominant paradigm of this new field, with transcranial alternating current stimulation (tACS) just emerging. Anodal stimulation with tDCS has excitatory effects on the underlying cortex, whereas cathodal stimulation has inhibitory effects. Because both electrodes have significant brain effects when placed at cephalic areas, the term “reference” electrode should be avoided. Most studies have applied tDCS to the motor cortex, the prefrontal cortex, and the occipital cortex. Applications of tDCS include modulation of electrophysiological and hemodynamic brain activity, symptom reduction in neurological and psychiatric pathology, and cognitive improvement in healthy volunteers or clinical populations. There is evidence of motor improvement in patients with stroke, pain reduction in fibromyalgia, improved mood in patients with unipolar or bipolar depression, and reduced c...

Novel case of familial normal pressure hydrocephalus

effect, as her psychosocial status was stationary. The effect of escitalopram and aripiprazole for the treatment of NSS has been individually explored. Because of the dopaminergic activating effect in the ventral tegmental area and the frontal cortex, aripiprazole plays a role in enhancing motivation. Recent research indicates that a combination of antidepressant and second-generation antipsychotic may provide a better therapeutic effect for NSS. Although escitalopram augmentation with antipsychotics showed no significant difference to placebo, the efficacy of escitalopram with an individual antipsychotic has yet to be clarified. It is generally accepted that cortical dopamine increases under 5-HT1 upregulation and 5-HT2 downregulation. Besides the D2 partial agonist effect of aripiprazole, both aripiprazole and escitalopram can be viewed as 5-HT1A receptor agonists. Escitalopram increases serotonin in the synapse, while aripiprazole is a 5-HT1A partial agonist. Therefore, the synergic effect on 5-HT1A somatodendritic autoreceptors may reduce 5-HT2A inhibition on dopaminergic neurons, then cause significant prefrontal dopamine release. This case indicates that a combination of aripiprazole and escitalopram is beneficial for NSS. The clinical improvement may take several months’ observation. Further study is needed to examine whether the regimens actually improve the daily function of simple schizophrenia.

The Superior Frontal Transsulcal Approach to the Anterior Ventricular System: Exploring the Sulcal and Subcortical Anatomy Using Anatomic Dissections and Diffusion Tensor Imaging Tractography

OBJECTIVEnTo explore the superior frontal sulcus (SFS) morphology, trajectory of the applied surgical corridor, and white matter bundles that are traversed during the superior frontal transsulcal transventricular approach.nnnMETHODSnTwenty normal, adult, formalin-fixed cerebral hemispheres and 2 cadaveric heads were included in the study. The topography, morphology, and dimensions of the SFS were recorded in all specimens. Fourteen hemispheres were investigated through the fiber dissection technique whereas the remaining 6 were explored using coronal cuts. The cadaveric heads were used to perform the superior frontal transsulcal transventricular approach. In addition, 2 healthy volunteers underwent diffusion tensor imaging and tractography reconstruction studies.nnnRESULTSnThe SFS was interrupted in 40% of the specimens studied and was always parallel to the interhemispheric fissure. The proximal 5 cm of the SFS (starting from the SFS precentral sulcus meeting point) were found to overlie the anterior ventricular system in all hemispheres. Five discrete white matter layers were identified en route to the anterior ventricular system (i.e., the arcuate fibers, the frontal aslant tract, the external capsule, internal capsule, and the callosal radiations). Diffusion tensor imaging studies confirmed the fiber tract architecture.nnnCONCLUSIONSnWhen feasible, the superior frontal transsulcal transventricular approach offers a safe and effective corridor to the anterior part of the lateral ventricle because it minimizes brain retraction and transgression and offers a wide and straightforward working corridor. Meticulous preoperative planning coupled with a sound microneurosurgical technique are prerequisites to perform the approach successfully.

Approaching the Atrium Through the Intraparietal Sulcus: Mapping the Sulcal Morphology and Correlating the Surgical Corridor to Underlying Fiber Tracts

BACKROUNDnAlthough the operative corridor used during the intraparietal transsulcal approach to the atrium has been previously investigated, most anatomical studies focus on its relationship to the optic radiations.nnnOBJECTIVEnTo study the intraparietal sulcus (IPS) morphology and to explore the subcortical anatomy with regard to the surgical trajectory used during the intraparietal transsulcal tranventricular approach.nnnMETHODSnTwenty-five adult, formalin fixed, cerebral hemispheres were investigated. Fifteen underwent the Klingler procedure and were dissected in a lateromedial direction using the fiber microdissection technique. The trajectory of the dissection resembled that of real operative settings. The remaining 10 hemispheres were cut along the longitudinal axis of the sulcus in order to correlate its surface anatomy to corresponding parts of the ventricular system.nnnRESULTSnIPS demonstrated an interrupted course in 36% of the specimens while its branching pattern was variable. The sulcus anterior half was found to overly the atrium in all occasions. Four discrete, consecutive white matter layers were identified en route to the atrium, ie, the arcuate fibers, the arcuate segment of the superior longitudinal fasciculus, the corona radiata and tapetum, with the arcuate segment being near to the dissection trajectory.nnnCONCLUSIONnGiven the angle of brain transgression during the intraparietal approach, we found the optimal dissection area to be the very middle of the sulcus. The IPS-postcentral sulcus meeting point, in contrast to previous thought, proved to risk potential injury to the arcuate segment of the superior longitudinal fasciculus, thus affecting surgical outcome.

Finger tapping and verbal fluency post-tap test improvement in INPH: its value in differential diagnosis and shunt-treatment outcomes prognosis

BackgroundIdiopathic normal pressure hydrocephalus (INPH) diagnosis is challenging as it can be mimicked by other neurological conditions, such as neurodegenerative dementia and motor syndromes. Additionally, outcomes after lumbar puncture (LP) tap test and shunt treatment may vary due to the lack of a common protocol in INPH assessment. The present study aimed to assess whether a post-LP test amelioration of frontal cognitive dysfunctions, characterizing this syndrome, can differentiate INPH from similar neurological conditions and whether this improvement can predict INPH post–shunt outcomes.MethodSeventy-one consecutive patients referred for INPH suspicion and LP testing, were enrolled. According to the consensus guidelines criteria, 29 patients were diagnosed as INPH and 42 were assigned an alternative diagnosis (INPH-like group) after reviewing clinical, neuropsychological and imaging data, and before LP results. A comprehensive neuropsychological assessment for frontal executive, upper extremity fine motor functions, aphasias, apraxias, agnosias and gait evaluation were administered at baseline. Executive, fine motor functions and gait were re-examined post-LP test in all patients and post-shunt placement in INPH patients.ResultsOf the INPH patients, 86.2% showed cognitive amelioration in the post-LP test; in addition, all but one (97%) presented with neurocognitive and gait improvement post-shunt. Verbal phonological fluency and finger tapping task post-LP improvement predicted positive clinical outcome post-shunt. None of the INPH-like group presented with neurocognitive improvement post-LP.ConclusionsPost-LP amelioration of verbal fluency and finger tapping deficits can differentiate INPH from similar disorders and predict positive post-shunt clinical outcome in INPH. This becomes of great importance when gait assessment is difficult to perform in clinical practice.