Motor and language resting state functional magnetic resonance imaging in brain tumor patients

Background and purpose: Resting state functional magnetic resonance (RS-fMRI) correlation with pre-surgical functional status in patients with brain tumors is scarcely documented in the present literature. Aim of the present study was to investigate the validity of RS-fMRI as potential preoperative functional mapping tool in tumor brain surgery by exploring the association of motor and language RS-fMRI networks with subjects’ preoperative performance on motor and language clinical assessment respectively in patients with brain tumor. Materials and methods: 85 patients presented with brain tumor entities and 27 healthy controls were prospectively recruited for the present study. Clinical sample was subdivided into two groups according to mass localization: patients with tumors in proximity to motor cortex (n=59) underwent clinical examination for gross (paresis- muscle weakness) and fine (finger tapping) motor deficits. Patients harboring tumors in proximity to the left inferior frontal gyrus (n=35) were clinically assessed for apparent (expressive aphasia) and subtle language function (phonological verbal fluency) disturbances. All patients and healthy subjects underwent RS-fMRI with motor and language resting networks being derived by Independent Component Analysis (ICA). Results: In the motor group, patients with paresis demonstrated significantly (p=<0.01) reduced resting state BOLD-signal intensity in ipsilesional motor cortex in comparison to the respective one in contralesional-intact motor cortex. Significantly (p<0.01) decreased BOLD-signal intensity was additionally noticed in ipsilesional motor cortex of patients with paresis in comparison to patients with normal muscle strength. Furthermore, in patients with intact muscle strength, a strong positive correlation (r=0.70, p<0.01) between ipsilesional pre-central gyrus BOLD-signal and performance on finger tapping task was demonstrated. Compared to the healthy group, clinical motor group showed reduced resting state network activity, with patients’ ipsilesional pre- central gyrus BOLD-signal intensity to be significantly (p<0.01) lower than normals’ left and right pre-central gyri BOLD-signal intensities. Concerning language group, patients presented with expressive aphasia exhibited significantly (p=<0.01) reduced RS-fMRI BOLD-signal intensity in left inferior frontal gyrus (Broadmann area 44) when compared with patients without aphasia. In non-aphasic patients, a strong positive correlation (r=0.70, P<0.01) between left inferior frontal gyrus’ BOLD-signal intensity and phonological fluency scoring was demonstrated. Similarly with the motor group, language group also showed significantly (p=<0.01) reduced left inferior gyrus RS- fMRI BOLD-signal when compared to healthy controls. Finally, RS-fMRI BOLD signal was not observed to have an association with demographic parameters (age, gender) for both clinical and healthy groups and with tumor histopathological grading for both motor and language clinical groups. Conclusions: Our findings show a significant affection of motor and language RS-fMRI networks’ BOLD-signal intensity by the presence of a tumor and a correlation with clinical performance of patients providing thus evidence for the functional validity of RS-fMRI in brain tumor patients; our results indicate therefore, that RS-fMRI may be a valuable complementary tool for preoperative mapping of eloquent areas, at least in patients who cannot cooperate satisfactory in a traditional task-based motor and language fMRI

Idiopathic Intracranial Hypertension: Epidemiology, pathophysiology, clinical features and contemporary management.

Idiopathic Intracranial Hypertension (IIH) is a syndrome of increased intracranial pressure (ICP) without evident cause. The exact pathogenesis of IIH remains elusive but it is also plausible that the syndrome represents the common final pathway of several different mechanisms. IIH has an estimated incidence of 1-3 per 100 000 and a predilection for obese women of childbearing age.  Presentation involves symptomatology and semiology of elevated intracranial pressure with headache being the most common. Visual disturbances can be devastating, progressive and may result in permanent visual loss. Moreover, pulsatile tinnitus is frequently encountered. However, asymptomatic presentations are also not uncommon with patients diagnosed after routine ophthalmological examination illustrates papilledema. Diagnosis is based upon the Friedman’s criteria. Absence of hydrocephalus or mass lesion and normal cerebrospinal fluid (CSF) composition need to be confirmed. Several treatment modalities have been suggested, varying from non-surgical (weight loss, drugs such as acetazolamide, serial lumbar puncture) to interventional and surgical (CSF diversion procedures, optic nerve sheath fenestration (ONSF), endovascular venous sinus stenting, or even bariatric surgery). There are very few RCTs to critically assess these therapies and, consequently, no consensus on the optimal management of IIH.

Dissociation between visuospatial neglect assessment tasks and its neuroanatomical substrates: a case report

Visuospatial neglect possesses significant heterogeneity in clinical features and neuroanatomical substrates. Behavioral dissociations on different neglect tasks have been reported in the past, and the investigation of their respective anatomical correlates at cortical and, to a lesser degree, subcortical levels has been attempted in stroke studies. We report a patient with a neoplasm occupying the right ventral post-central gyrus and anterior supramarginal gyrus. The patient was admitted preoperatively with dissociation on the performance of neglect tasks, showing clinical deficits in the line bisection task and clock drawing, but not on the cancelation task. The patient underwent an awake craniotomy for tumor excision. Intraoperative visuospatial mapping was employed by applying direct electrical stimulation (DES) to the supramarginal gyrus and the ventral branch of the superior longitudinal fasciculus (SLF III) during the line bisection task. According to our findings, DES was ineffective at the cortical level, but it induced strong rightward bias when applied subcortically at the SLF III. By combining our preoperative and intraoperative anatomical and clinical data, we suggest that the posterior part of the SLF III might have a distinct role in the perceptual component of neglect. Our findings are discussed within the context of previous literature supporting the notion that particular behavioral features of spatial neglect are mediated by different white-matter connections

Deciphering the frontostriatal circuitry through the fiber dissection technique: direct structural evidence on the morphology and axonal connectivity of the fronto-caudate tract

OBJECTIVE The authors sought to investigate the very existence and map the topography, morphology, and axonal connectivity of a thus far ill-defined subcortical pathway known as the fronto-caudate tract (FCT) since there is a paucity of direct structural evidence regarding this pathway in the relevant literature. METHODS Twenty normal adult cadaveric formalin-fixed cerebral hemispheres (10 left and 10 right) were explored through the fiber microdissection technique. Lateral to medial and medial to lateral dissections were carried out in a tandem manner in all hemispheres. Attention was focused on the prefrontal area and central core since previous diffusion tensor imaging studies have recorded the tract to reside in this territory. RESULTS In all cases, the authors readily identified the FCT as a fan-shaped pathway lying in the most medial layer of the corona radiata and traveling across the subependymal plane before terminating on the superolateral margin of the head and anterior part of the body of the caudate nucleus. The FCT could be adequately differentiated from adjacent fiber tracts and was consistently recorded to terminate in Brodmann areas 8, 9, 10, and 11 (anterior pre-supplementary motor area and the dorsolateral, frontopolar, and fronto-orbital prefrontal cortices). The authors were also able to divide the tract into a ventral and a dorsal segment according to the respective topography and connectivity observed. Hemispheric asymmetries were not observed, but instead the authors disclosed asymmetry within the FCT, with the ventral segment always being thicker and bulkier than the dorsal one. CONCLUSIONS By using the fiber microdissection technique, the authors provide sound structural evidence on the topography, morphology, and connectional anatomy of the FCT as a distinct part of a wider frontostriatal circuitry. The findings are in line with the tract&apos;s putative functional implications in high-order motor and behavioral processes and can potentially inform current surgical practice in the fields of neuro-oncology and functional neurosurgery

Effect of constant-current pallidal deep brain stimulation for primary dystonia on cognition, mood and quality of life: Results from a prospective pilot trial

Objective: Knowledge on the effects of DBS on cognitive functions is limited and no data exists on the effects of constant-current DBS (CC-GPi-DBS), which appears to prevail over constant-voltage stimulation. Our aim was to prospectively assess the effect of Constant-Current-GPi-DBS, using an 8-contact lead, on cognition, mood and quality of life. Patients and Methods: Ten patients aged 27-49 underwent prospective neuropsychological assessment using dedicated tests. Various cognitive domains (intelligence, executive functions, memory, attention, visuo-spatial perception, verbal intelligence) as well as emotional state and quality of life were examined preoperatively and 1, 6 and 12 months after continuous constant-current DBS. Results: Patients performed preoperatively below average on information processing speed, phonemic verbal fluency and working memory. At 6-months there was an improvement in phonemic verbal fluency (p &lt; .05), which was retained at 12-months postoperatively (p = .05). Results also showed marginal improvement in the Trail Making-A test (p = .051) and the Stroop colour-word test (p &lt; .05). Despite improvement in Quality of Life (Physical and Mental Component improved by 32.42% and 29.46% respectively), patients showed no discernible change in anxiety and depression status. Conclusions: CC-GPi-DBS for primary dystonia has no discernible negative impact on cognition and mood. If anything, we noted an improvement of certain cognitive functions