Parietotemporal Regions Research Articles

EEG biomarkers of Epileptiform Activity in Relation to Alzheimer’s Disease Biomarkers

AbstractBackgroundGrowing evidence suggests that the imbalance between excitability and inhibitory neural activity is a key aspect of cognitive decline. Subclinical epileptiform activity (SEA) has been indicated as a marker of increased cortical excitability. While SEA is considered as a benign EEG sign in the elderly population, recent studies demonstrated its role in the progression of Alzheimer’s disease. The aim of our study was to investigate the relevance and phenotype of SEA in clinically healthy elderly population.MethodWe studied 62 elderly subjects determined as healthy based on physical, neuropsychology, neuroimaging (MRI), and serological workup. All subjects underwent 24‐h Holter electroencephalography (EEG), visual analysis was conducted by two independent raters. Subjects were classified into EEG positive (EEG+) and negative (EEG‐) groups based on detecting epileptiform activity on their EEG. Neuropsychology battery and structural MRI results were compared between the groups.ResultsEEG analysis showed epileptiform activity in 26% of cases. EEG positivity was associated with significantly lower verbal and category fluency subscores on Addenbrooke Cognitive Examination (p=0,03 and p=0,01). This group also performed worse on both Trail Making Test A and B (p =0,02 and 0,003 respectively). Age and education had a significant effect on neuropsychological performance in both groups. Structural MR analysis showed significant group differences in various areas, particularly in the parietotemporal regions (p=0,001). Interestingly, EEG+ patients had larger external temporal brain volume bilaterally (p<0,001) and reduced medial parietal volume (p=0,001).ConclusionPresence of SEA among healthy elderly shows a discrete but significant association with decreased cognitive performance in certain subdomains, as well as a special imaging phenotype. Our results underscore the relevance of data suggesting that cortical hyperexcitability associate with parietal atrophy and preserved temporal structures. In Alzheimer’s disease, the detailed representation corresponds to the hippocampal sparing phenotype. Considering our findings, SEA might associate with an increased risk for cognitive decline even in healthy individuals.

Functional network disruption in cognitively unimpaired autosomal dominant Alzheimer's disease: a magnetoencephalography study.

Understanding the nature and onset of neurophysiological changes, and the selective vulnerability of central hub regions in the functional network, may aid in managing the growing impact of Alzheimer's disease on society. However, the precise neurophysiological alterations occurring in the pre-clinical stage of human Alzheimer's disease remain controversial. This study aims to provide increased insights on quantitative neurophysiological alterations during a true early stage of Alzheimer's disease. Using high spatial resolution source-reconstructed magnetoencephalography, we investigated regional and whole-brain neurophysiological changes in a unique cohort of 11 cognitively unimpaired individuals with pathogenic mutations in the presenilin-1 or amyloid precursor protein gene and a 1:3 matched control group (n = 33) with a median age of 49 years. We examined several quantitative magnetoencephalography measures that have been shown robust in detecting differences in sporadic Alzheimer's disease patients and are sensitive to excitation-inhibition imbalance. This includes spectral power and functional connectivity in different frequency bands. We also investigated hub vulnerability using the hub disruption index. To understand how magnetoencephalography measures change as the disease progresses through its pre-clinical stage, correlations between magnetoencephalography outcomes and various clinical variables like age were analysed. A comparison of spectral power between mutation carriers and controls revealed oscillatory slowing, characterized by widespread higher theta (4-8 Hz) power, a lower posterior peak frequency and lower occipital alpha 2 (10-13 Hz) power. Functional connectivity analyses presented a lower whole-brain (amplitude-based) functional connectivity in the alpha (8-13 Hz) and beta (13-30 Hz) bands, predominantly located in parieto-temporal hub regions. Furthermore, we found a significant hub disruption index for (phase-based) functional connectivity in the theta band, attributed to both higher functional connectivity in 'non-hub' regions alongside a hub disruption. Neurophysiological changes did not correlate with indicators of pre-clinical disease progression in mutation carriers after multiple comparisons correction. Our findings provide evidence that oscillatory slowing and functional connectivity differences occur before cognitive impairment in individuals with autosomal dominant mutations leading to early onset Alzheimer's disease. The nature and direction of these alterations are comparable to those observed in the clinical stages of Alzheimer's disease, suggest an early excitation-inhibition imbalance, and fit with the activity-dependent functional degeneration hypothesis. These insights may prove useful for early diagnosis and intervention in the future.

Treacherous Territory: Temple Fillers and Tissue Necrosis

Abstract Temporal region of the face is considered the most promising facial region for inducing panfacial effects, playing an increasingly important role in facial contouring and rejuvenation surgeries, which in turn has led to a rapid growth in the demand for aesthetic correction for temporal hollowing. In order to correct this issue and achieve a more youthful appearance, filler injections can be used. Although this procedure is generally safe and is increasingly popular, complications may happen. Complications include visual loss, neurological deficits, embolism, and non-thrombotic pulmonary embolism. These complications are thought to result from injection of filler material into facial arteries and veins. We describe here a patient who developed pain in the parieto-temporal region following hyaluronic acid (HA) injection for temporal augmentation, which was complicated by tissue necrosis and alopecia. This was managed with hyaluronidase injection and aspirin tablets. Patient was followed for 6 months period after which she had complete hair growth and total resolution of skin necrosis without any scar formation. Since complications of HA injection are wide and serious, practitioners should always be aware of potential consequences of such procedures.

Brain magnetic resonance imaging review suggests unrecognised hypoglycaemia in childhood.

Neonatal and early-life hypoglycaemia, is a frequent finding but is often non-specific and asymptomatic, making detection and diagnosis challenging. Hypoglycaemia-induced cerebral injury can be identified by magnetic resonance imaging (MRI) changes in cerebral white matter, occipital lobes, and posterior parietotemporal regions. It is unknown if children may have hypoglycaemic brain injury secondary to unrecognised hypoglycaemia in early life. We have examined retrospective radiological findings of likely brain injury by neuroimaging to investigate the existence of previous missed hypoglycaemic events. Retrospective MRI data in children in a single tertiary centre, over a ten-year period was reviewed to identify potential cases of unrecognised early-life hypoglycaemia. A detailed search from an electronic radiology repository involved the term "hypoglycaemia'' from text-based reports. The initial report was used for those who required serial scanning. Images specific to relevant reports were further reviewed by a designated paediatric neuroradiologist to confirm likely hypoglycaemia induced brain injury. Medical records of those children were subsequently reviewed to assess if the hypoglycaemia had been diagnosed prior to imaging. A total of 107 MR imaging reports were identified for review, and 52 (48.5%) showed typical features strongly suggestive of hypoglycaemic brain injury. Medical note review confirmed no documented clinical information of hypoglycaemia prior to imaging in 22 (42%) patients, raising the likelihood of missed hypoglycaemic events resulting in brain injury. We have identified the existence of unrecognised childhood hypoglycaemia through neuroimaging review. This study highlights the need for heightened awareness of early life hypoglycaemia to prevent adverse neurological outcomes later in childhood.

Challenges in Intraventricular Meningiomas Surgery, Case Presentation and Review of the Literature

Objectives: Review on the management of meningiomas of the ventricular atrium according to what has been reported in the literature and in the experience of our institution. Background: Intraventricular meningiomas represent 1 to 5% of meningiomas. Approaches are suggested depending on tumor location and extension, proximity to eloquent areas or pathways (motor, sensory, optic radiation, language), vascular pedicles. In this case, it is a 41-year-old female patient who presents a stabbing headache in the left parieto-temporal region with an intensity of 7/10. Clinically mental functions with impaired retrograde memory and anterograde, acalculia, preserved judgment and abstraction, bradilalia, bradypsychia, for which he went for evaluation and a cranial tomography study with contrast was carried out, evidencing intraventricular extra axial tumor lesion, for which he underwent surgical procedure through excision of a probable left intraventricular extra axial lesion meningioma vs choroid plexus papilloma.

2.5-Year changes of connectivity dynamism are relevant for physical and cognitive deterioration in multiple sclerosis

Background: In MS, functional connectivity (FC) dynamism may influence disease evolution. Objectives: The objective is to assess time-varying functional connectivity (TVFC) changes over time at 2.5-year follow-up in MS patients according to physical and cognitive worsening. Methods: We collected 3T magnetic resonance imaging (MRI) for TVFC assessment (performed using sliding-window analysis of centrality) and clinical evaluations at baseline and 2.5-year follow-up from 28 healthy controls and 129 MS patients. Of these, 79 underwent baseline and follow-up neuropsychological assessment. At 2.5 years, physical/cognitive worsening was defined according to disability/neuropsychological score changes. Results: At follow-up, 25/129 (19.3%) MS patients worsened physically and 14/79 (17.7%) worsened cognitively. At baseline, MS patients showed reduced TVFC versus controls. At 2.5-year follow-up, no TVFC changes were detected in controls. Conversely, TVFC decreased over time in parieto-temporal regions in stable MS patients and in default-mode network in worsened MS. In physically worsened MS, basal ganglia TVFC reductions were also found. Reduced TVFC over time in the putamen in physically worsened and reduced TVFC in the precuneus in cognitively worsened were significant versus stable MS. Discussion: At 2.5-year follow-up, default-mode network TVFC reductions were found in worsening MS. Moreover, reduced deep gray matter TVFC characterized physically worsened patients, whereas precuneus involvement characterized cognitively worsened MS patients.

Comparison of 18F-FDG PET and arterial spin labeling MRI in evaluating Alzheimer’s disease and amnestic mild cognitive impairment using integrated PET/MR

BackgroundDeveloping biomarkers for early stage AD patients is crucial. Glucose metabolism measured by 18F-FDG PET is the most common biomarker for evaluating cellular energy metabolism to diagnose AD. Arterial spin labeling (ASL) MRI can potentially provide comparable diagnostic information to 18F-FDG PET in patients with neurodegenerative disorders. However, the conclusions about the diagnostic performance of AD are still controversial between 18F-FDG PET and ASL. This study aims to compare quantitative cerebral blood flow (CBF) and glucose metabolism measured by 18F-FDG PET diagnostic values in patients with Alzheimer’s disease (AD) and amnestic mild cognitive impairment (aMCI) using integrated PET/MR.ResultsAnalyses revealed overlapping between decreased regional rCBF and 18F-FDG PET SUVR in patients with AD compared with NC participants in the bilateral parietotemporal regions, frontal cortex, and cingulate cortex. Compared with NC participants, patients with aMCI exclusively demonstrated lower 18F-FDG PET SUVR in the bilateral temporal cortex, insula cortex, and inferior frontal cortex. Comparison of the rCBF in patients with aMCI and NC participants revealed no significant difference (P > 0.05). The ROC analysis of rCBF in the meta-ROI could diagnose patients with AD (AUC, 0.87) but not aMCI (AUC, 0.61). The specificity of diagnosing aMCI has been improved to 75.56% when combining rCBF and 18F-FDG PET SUVR.ConclusionASL could detect similar aberrant patterns of abnormalities compared to 18F-FDG PET in patients with AD compared with NC participants but not in aMCI. The diagnostic efficiency of 18F-FDG-PET for AD and aMCI patients remained higher to ASL. Our findings support that applying 18F-FDG PET may be preferable for diagnosing AD and aMCI.

Occult Pheochromocytoma and Acute Ischaemic Stroke in Young Adult: Cause or Association

Pheochromocytoma is a rare catecholamine-secreting tumours of chromaffin tissues that cause a constellation of symptoms. It is closely associated with endocrine hypertension that can be masked, sustained or paroxysmal leading to hypertensive crisis, resulting in vascular and non-vascular complications and rarely cerebral ischaemia and stroke. A healthy 22 year old male reported with acute Right upper limb(RUL) monoplegia and Motor aphasia for five days with raised blood pressure levels. hypertonia was present, deep tendon reflexes were exaggerated in RUL and Right Plantar was extensor. General and systemic findings were nonsignificant . Routine investigations showed thrombocytosis and M.R.I. Brain was suggestive of acute infarction of Left Parieto-Temporal region. Renal doppler, Carotid Intima Media Thickness, Cerebral Angiogram, 2D-E.C.H.O. and Fundoscopy were normal. AntinuclearAntibody was negative. Contrast CT of abdomen revealed right adrenal mass suggestive of isolated Pheochromocytoma. Vanyl-Mandelic Acid was positive. Patient was stabilised and managed conservatively for 4 weeks followed by adrenalectomy and appropriate medical therapy. Patient is on regular followup and does not seem to require any antihypertensives or any other intervention. Pheochromocytoma is a notorious tumor and a great masquerader specially in young adults. A keen eye, routine checkups and evaluation is the key to detecting and preventing its associated morbidity and mortality.

A - 27 Early-Onset Alzheimer's Disease: Indications of Psychosis Severity and Disease Progression.

Early-onset Alzheimer's disease (EOAD) comprises about 5% of ad cases and is associated with delays in diagnosis and aggressive course. Psychotic symptoms are frequent in ad and often include delusions of infidelity and hallucinations. When present, ad with psychosis is accompanied by elevated levels of depression and greater functional impairment. This case expands upon the existing literature on EOAD through the timeline of a complex psychosis presentation accompanied by rapid cognitive decline. 63-year-old, Hispanic, woman with progressive cognitive changes (e.g., confusion, forgetfulness, word-finding difficulties, disorganization) that emerged 5years prior to seeking neurological consultation. Psychosis symptoms (i.e., auditory/visual hallucinations, delusions), in the context of real events (i.e., husband's previous infidelity), developed simultaneously. These pervasive symptoms have contributed to social withdrawal, persistent suicidal tendencies, and impaired IADLs. Neuroimaging suggested hypometabolism in the parietotemporal regions with precuneus and posterior cingulate gyri involvement. The evaluation revealed fairly generalized cognitive decline. Basic attention, working memory, visual abstract reasoning, and phonemic fluency were intact. Visual integration/visuoconstruction were reduced. Impairments emerged in processing speed, rapid cognitive flexibility, cognitive inhibition, conceptualization, visuospatial orientation, semantic fluency, confrontation naming, and visual and verbal encoding and retention (with rapid forgetting). She endorsed moderately elevated symptoms of depression and anxiety. The pattern of cognitive and functional deficits are all suggestive of an ad process. Her age, sex, significant neuroimaging findings, report of earliest cognitive symptoms, and family history reinforce an EOAD etiology. Significant behavioral changes are often associated with increased cognitive impairment and in turn, may mark the progression/stage of the disease.

Cortical Synchrony and Information Flow during Transition from Wakefulness to Light Non-Rapid Eye Movement Sleep.

Sleep is a highly stereotyped phenomenon, requiring robust spatiotemporal coordination of neural activity. Understanding how the brain coordinates neural activity with sleep onset can provide insights into the physiological functions subserved by sleep and the pathologic phenomena associated with sleep onset. We quantified whole-brain network changes in synchrony and information flow during the transition from wakefulness to light non-rapid eye movement (NREM) sleep, using MEG imaging in a convenient sample of 14 healthy human participants (11 female; mean 63.4 years [SD 11.8 years]). We furthermore performed computational modeling to infer excitatory and inhibitory properties of local neural activity. The transition from wakefulness to light NREM was identified to be encoded in spatially and temporally specific patterns of long-range synchrony. Within the delta band, there was a global increase in connectivity from wakefulness to light NREM, which was highest in frontoparietal regions. Within the theta band, there was an increase in connectivity in fronto-parieto-occipital regions and a decrease in temporal regions from wakefulness to Stage 1 sleep. Patterns of information flow revealed that mesial frontal regions receive hierarchically organized inputs from broad cortical regions upon sleep onset, including direct inflow from occipital regions and indirect inflow via parieto-temporal regions within the delta frequency band. Finally, biophysical neural mass modeling demonstrated changes in the anterior-to-posterior distribution of cortical excitation-to-inhibition with increased excitation-to-inhibition model parameters in anterior regions in light NREM compared with wakefulness. Together, these findings uncover whole-brain corticocortical structure and the orchestration of local and long-range, frequency-specific cortical interactions in the sleep-wake transition.SIGNIFICANCE STATEMENT Our work uncovers spatiotemporal cortical structure of neural synchrony and information flow upon the transition from wakefulness to light non-rapid eye movement sleep. Mesial frontal regions were identified to receive hierarchically organized inputs from broad cortical regions, including both direct inputs from occipital regions and indirect inputs via the parieto-temporal regions within the delta frequency range. Biophysical neural mass modeling revealed a spatially heterogeneous, anterior-posterior distribution of cortical excitation-to-inhibition. Our findings shed light on the orchestration of local and long-range cortical neural structure that is fundamental to sleep onset, and support an emerging view of cortically driven regulation of sleep homeostasis.

Evaluation of whole-brain oxygen metabolism in Alzheimer's disease using QSM and quantitative BOLD

ObjectiveThe objective of this study was to evaluate the whole-brain pattern of oxygen extraction fraction (OEF), cerebral blood flow (CBF), and cerebral metabolic rate of oxygen consumption (CMRO2) perturbation in Alzheimer's disease (AD) and investigate the relationship between regional cerebral oxygen metabolism and global cognition. MethodsTwenty-six AD patients and 25 age-matched healthy controls (HC) were prospectively recruited in this study. Mini-Mental State Examination (MMSE) was used to evaluate cognitive status. We applied the QQ-CCTV algorithm which combines quantitative susceptibility mapping and quantitative blood oxygen level-dependent models (QQ) for OEF calculation. CBF map was computed from arterial spin labeling and CMRO2 was generated based on Fick's principle. Whole-brain and regional OEF, CBF, and CMRO2 analyses were performed. The associations between these measures in substructures of deep brain gray matter and MMSE scores were assessed. ResultsWhole brain voxel-wise analysis showed that CBF and CMRO2 values significantly decreased in AD predominantly in the bilateral angular gyrus, precuneus gyrus and parieto-temporal regions. Regional analysis showed that CBF value decreased in the bilateral caudal hippocampus and left rostral hippocampus and CMRO2 value decreased in left caudal and rostral hippocampus in AD patients. Considering all subjects in the AD and HC groups combined, the mean CBF and CMRO2 values in the bilateral hippocampus positively correlated with the MMSE score. ConclusionCMRO2 mapping with the QQ-CCTV method - which is readily available in MR systems for clinical practice - can be a potential biomarker for AD. In addition, CMRO2 in the hippocampus may be a useful tool for monitoring cognitive impairment.

Effects of conscious connected breathing on cortical brain activity, mood and state of consciousness in healthy adults

Breathwork as a means of inducing non-ordinary states of consciousness is gaining traction as a potential therapeutic modality. We examined the effects of breathwork (in the form of connected breathing) on electroencephalography (EEG) and mood in 20 healthy participants (aged between 23 and 39 years (female = 11, Mage = 29). In addition, to compare with other means of inducing non-ordinary states of consciousness, we assessed the subjective effects of breathwork using the 11 Dimension Altered State of Consciousness questionnaire. EEG spectral power analysis of eyes closed rest recordings before and after the breathwork session showed a decrease in delta (1–4 Hz) and theta (4–8 Hz) frequencies in frontotemporal and parietal regions, respectively no changes were seen in Alpha (9–12 Hz) and Beta (12–30 Hz) bands. However, after decomposing the beta waves in Beta 1 (12–15 Hz), Beta 2 (15–20 Hz), Beta 3 (20–30 Hz), decreases in power were observed across Beta1 and Beta 2 in parietotemporal regions. Notably, the spectral power in gamma increased in experienced practitioners. Scores on the Profile of Mood States questionnaire showed a reduction in negative affect (anger, tension, confusion, and depression) and an increase in esteem. Scores on the 11D-ASC scale indicated that subjective experiences during breathwork were similar to those after medium to high doses of psilocybin, suggesting the occurrence of experiences of mystical quality. Present results indicate that breathwork changes brain activity and mood, and induces mystical experiences. These results are promising and suggest that such techniques could be useful to improve mental well-being.

Manejo multimodal de aneurisma cirsoideo. Reporte de un caso y revisión de la literatura

Scalp arteriovenous malformations (AVMs), commonly known as cirsoid aneurysms, are complex collections of arteries and veins that communicate directly. It has been postulated that AVMs occur both through the activation of inactive fistulous lesions and through the formation of new fistulous vascular channels through the canalization of injured vessels. Depending on their size and complexity, a variety of strategies can be used to treat them. The case of a 53-year-old male is presented who came for evaluation due to an increase in the volume of a pulsating lesion that extended from the right parietotemporal region accompanied by holocraneal headache and tinnitus. A cerebral angiotomography was performed in which a lesion composed of ectatic serpentine images, with a right extracranial location, subsequently diagnostic cerebral angiography was performed demonstrating a right frontoparietal fistulous and plexiform arteriovenous shunt fed by afferents from the right superficial temporal, posterior auricular, occipital and middle meningeal arteries, with drainage through a varicose and ectatic vein towards the external jugular vein. An endovascular embolization of the arteriovenous shunt was performed via the femoral route in two stages, achieving a “pressure cooker” construction to perform the injection of embolizing fluid and have a subtotal embolization of 93%, with this it was possible to perform a microsurgical resection with a right fronto-parietal-temporal approach resecting the deepest part, leaving the scalp with embolized vessels without resecting. To close the surgical wound, a simple flap rotation was performed to cover the skin defect derived from its resection. The patient underwent post-resection cerebral panangiography, identifying the absence of arteriovenous shunt. Depending on the extent and anatomical complexity of the malformation, clinical manifestations may vary. More than 80% of AVMs will be present at birth and the rest may develop after head trauma or surgical interventions. Appropriate therapeutic intervention is needed through selective angiography, during which endovascular embolization of the major feeding vessels can be performed before open surgical intervention. Volume-based three-dimensional computed tomography reconstructions can be used for further planning. Surgical reduction of post-embolization arterial supply will reduce intraoperative hemorrhage, facilitating total surgical resection. Removal can result in large, full-thickness skin defects that may be difficult to reconstruct without compromising functional and cosmetic results. Keywords: Cirsoid aneurysm; multimodal management; treatment; endovascular; giant

Takotsubo cardiomyopathy associated with Herpes simplex encephalitis: A case report and literature review

Takotsubo cardiomyopathy (TCM) is a stress-induced cardiomyopathy characterized by transient left ventricular dysfunction. It can be triggered by various central nervous system pathologies including status epilepticus (SE) and N-methyl-d-aspartate receptor (NMDAr) encephalitis. Herpex simplex encephalitis (HSE) is a life-threatening, sporadic, encephalitis associated with focal or global cerebral dysfunction caused by herpes simplex viruses type 1(HSV-1), or less commonly, type 2(HSV-2). While approximately 20% of patients with HSE develop NMDAr antibodies, not all manifest with encephalitis clinically. We present here a 77-year-old woman admitted with HSV-1 encephalitis who presented with acute encephalopathy and seizure-like activity. Continuous EEG monitoring (cEEG) showed periodic lateralized epileptiform discharges (PLEDs) involving the left parietotemporal region but no evidence of electrographic seizures. Her early hospital course was complicated by TCM which subsequently resolved on repeat TTE. She demonstrated initial neurological improvement. However, five weeks later her mental status declined. Again, no seizures were appreciated on cEEG. Unfortunately, repeat studies including lumbar puncture and magnetic resonance imaging (MRI) of the brain were consistent with NMDAr encephalitis. She was treated with immunosuppression and immunomodulation therapies. To our knowledge we report the first case of TCM secondary to HSE without comorbid status epilepticus. However, further studies are needed to better understand the correlation between, and underlying pathophysiology of HSE and TCM, as well as any potential association with this presentation and subsequent development of NMDAr encephalitis.

Гемодинамическая асимметрия и альфа-асимметрия полушарий головного мозга человека при различных положениях тела

Hemispheric asymmetry has been intensively studied by psycho- and neurophysiology mostly using electroencephalography (EEG) and functional magnetic resonance imaging. However, there is little data available on the characteristics of bioelectrical and haemodynamic asymmetry of the human brain during postural changes. This pilot study introduces a combined technique of simultaneous recording of brain haemodynamic and bioelectric asymmetry in different body positions. The aim of the paper was to compare asymmetry coefficients in three different body positions and to establish cortex areas with the most active shift in blood flow and alpha power in response to postural changes. The research involved 12 healthy volunteers aged between 20 and 25 years (mean age 21.4 ± 1.5 years) evenly distributed by sex. Materials and methods. Bioelectric and haemodynamic activity of the brain was assessed by means of rheoencephalography and EEG, respectively. Rheographic index and spectral power of alpha waves were recorded in three body positions (sitting, supine and 45° head-down tilt), followed by the calculation of haemodynamic asymmetry (Khda) and alpha asymmetry (Kαa) coefficients. Results. Statistical analysis of Khda showed no sex differences or significant differences in this parameter between the body positions, which can be explained by direct effects of baroreflex and cerebrovascular autoregulation. Statistical comparison of Kαa of EEG signals from all electrode leads with each other and in each position demonstrated significant changes in Kαa of P3/P4, T5/T6 and F3/F4 pairs in male subjects. These findings can indicate that posterior parietal cortex of both hemispheres and left parietotemporal region, which play an important role in spatial perception, as well as dorsolateral prefrontal cortex, which participates in muscle tone regulation for posture correction, are actively involved in bioelectrical response to postural changes.

Inter-individual variability during neurodevelopment: an investigation of linear and nonlinear resting-state EEG features in an age-homogenous group of infants.

Electroencephalography measures are of interest in developmental neuroscience as potentially reliable clinical markers of brain function. Features extracted from electroencephalography are most often averaged across individuals in a population with a particular condition and compared statistically to the mean of a typically developing group, or a group with a different condition, to define whether a feature is representative of the populations as a whole. However, there can be large variability within a population, and electroencephalography features often change dramatically with age, making comparisons difficult. Combined with often low numbers of trials and low signal-to-noise ratios in pediatric populations, establishing biomarkers can be difficult in practice. One approach is to identify electroencephalography features that are less variable between individuals and are relatively stable in a healthy population during development. To identify such features in resting-state electroencephalography, which can be readily measured in many populations, we introduce an innovative application of statistical measures of variance for the analysis of resting-state electroencephalography data. Using these statistical measures, we quantified electroencephalography features commonly used to measure brain development-including power, connectivity, phase-amplitude coupling, entropy, and fractal dimension-according to their intersubject variability. Results from 51 6-month-old infants revealed that the complexity measures, including fractal dimension and entropy, followed by connectivity were the least variable features across participants. This stability was found to be greatest in the right parietotemporal region for both complexity feature, but no significant region of interest was found for connectivity feature. This study deepens our understanding of physiological patterns of electroencephalography data in developing brains, provides an example of how statistical measures can be used to analyze variability in resting-state electroencephalography in a homogeneous group of healthy infants, contributes to the establishment of robust electroencephalography biomarkers of neurodevelopment through the application of variance analyses, and reveals that nonlinear measures may be most relevant biomarkers of neurodevelopment.

Quantitative brain 18F-FDG PET/CT analysis in seronegative autoimmune encephalitis (P11-3.005)

<h3>Objective:</h3> To determine if PET/CT is abnormal in less differentiated forms of autoimmune encephalitis (AE), including seronegative AE and steroid-responsive encephalopathy with associated thyroiditis (SREAT), and whether specific patterns of dysmetabolism exist. <h3>Background:</h3> Brain ¹⁸F-FDG PET/CT (PET) has been established as a useful tool in evaluating AE. Specific patterns of dysmetabolism have been identified in patients with anti-N-methyl-D-aspartate (NMDA) and anti-leucine-rich-glioma-inactivated-1 (LGI-1) AE, and preliminary evidence suggests that PET dysmetabolism may correlate with clinical functional status. <h3>Design/Methods:</h3> We conducted a retrospective cross-sectional analysis of PET scans in people with seronegative AE and SREAT. Utilizing NeuroQ™ software, the Z-scores of 47 brain regions were calculated compared to healthy controls, displayed in heat maps, and visually and statistically compared between study groups and to previous data from NMDA and LGI1 cohorts. <h3>Results:</h3> Sixteen seronegative AE and 4 SREAT patients were identified. All PET scans demonstrated abnormal FDG uptake, while MRI, EEG and CSF were abnormal less frequently in both groups. Both seronegative and SREAT patients demonstrated hypometabolism in the medial frontal, inferior frontal and parieto-temporal regions, and hypermetabolism in the medial temporal lobes. Regions of dysmetabolism were significantly different from NMDA and LGI1 patient data, an effect driven by greater severity of dysmetabolism in the NMDA and LGI1 patients. Follow up scans for 3 seronegative AE patients suggest the degree of dysmetabolism on PET correlates with functional status. <h3>Conclusions:</h3> PET is a useful tool in the evaluation of autoimmune encephalitis. SREAT and seronegative AE represent less differentiated forms of AE. Though frequently abnormal, as anticipated, the pattern of dysmetabolism in SREAT and seronegative AE were less distinct than in NMDA and LGI-1. The pattern of dysmetabolism observed here in SREAT patients was not markedly distinct from seronegative AE patients, potentially supporting consideration of SREAT as a type of seronegative AE rather than a distinct disease entity. <b>Disclosure:</b> Dr. Roman has nothing to disclose. Dr. Sadaghiani has nothing to disclose. Dr. Diaz-Arias has nothing to disclose. Marion Le Marechal has nothing to disclose. Dr. Venkatesan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen Pharmaceuticals. The institution of Dr. Venkatesan has received research support from NIH. The institution of Dr. Venkatesan has received research support from MSRCF. The institution of Dr. Venkatesan has received research support from U.S. DOD. Dr. Probasco has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for NEJM Journal Watch Neurology.

Incidental Tc-99m MDP Uptake in Cortical-subcortical Parietotemporal Cerebral Area in a Patient with a History of Recent Ischemic Cerebrovascular Event who Underwent Whole-body Bone Scan.

The authors present Tc-99m methylene diphosphonate (MDP) uptake in the right parietotemporal area at whole-body bone scan (WBBS) in 75 years male patient with prostate adenocarcinoma Gleason score 3+4 (pT2N0Mx). No residual or metastatic disease was detected in the patient's Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography four months before WBBS. The patient had undetectable prostate-specific antigen levels and underwent WBBS to restage prostate cancer due to equivocal findings in previous WBBS. Current WBBS planar views revealed heterogeneous Tc-99m MDP uptake in the right parietotemporal area and the sphenoid bone in addition to equivocal uptake on the lower lumbar vertebrae. Single-photon emission computed tomography study to identify the MDP-avid lesion on the right cranial area revealed heterogeneous Tc-99m MDP uptake in the right parietotemporal area and sphenoid bone. The patient had a history of transsphenoidal surgery for a hypophyseal tumor two years ago and a recent cerebrovascular event (CVE). Diffusion-weighted magnetic resonance imaging revealed a cortical-subcortical patchy area of restricted diffusion in the parietotemporal region compatible with acute ischemia. Heterogeneous Tc-99m MDP uptake in the right parietotemporal area was attributed to recent CVE and secondary vascular-tissue change-related dystrophic calcification.

Regional cortical hypoperfusion and atrophy correlate with striatal dopaminergic loss in Parkinson's disease: a study using arterial spin labeling MR perfusion.

To investigate the relationship of the striatal dopamine transporter density to changes in the gray matter (GM) volume and cerebral perfusion in patients with Parkinson's disease (PD). We evaluated the regional cerebral blood flow (CBF) and GM volume, concurrently measured using arterial spin labeling and T1-weighted magnetic resonance imaging, respectively, as well as the striatal specific binding ratio (SBR) in 123I-N-ω-fluoropropyl-2β-carboxymethoxy-3β-(4-iodophenyl)nortropane (123I-FP-CIT) single-photon emission computed tomography in 30 non-demented patients with PD (15 men and 15 women; mean age, 67.2 ± 8.8years; mean Hoehn-Yahr stage, 2.2 ± 0.9). Voxel-wise regression analyses using statistical parametric mapping (SPM) were performed to explore the brain regions that showed correlations of the striatal SBR to the GM volume and CBF, respectively, with a height threshold of p < 0.0005 at the voxel level and p < 0.05 family-wise error-corrected at the cluster level. SPM analysis showed a significant positive correlation between the SBR and GM volume in the inferior frontal gyrus (IFG). Whereas, a positive correlation between the SBR and CBF was widely found in the frontotemporal and parietotemporal regions, including the IFG. Notably, the opercular part of the IFG showed significant correlations in both SPM analyses of the GM volume (r2 = 0.90, p < 0.0001) and CBF (r2 = 0.88, p < 0.0001). The voxel-wise analyses revealed the brain regions, mainly the IFG, that showed hypoperfusion and atrophy related to dopaminergic loss, which suggests that the progression of dopaminergic neurodegeneration leads to regional cortical dysfunction in PD.

An "Instantaneous" Response of a Human Visual System to Hue: An EEG-Based Study.

(1) The article presents a new technique to interpret biomedical data (EEG) to assess cortical responses to continuous color/hue variations. We propose an alternative approach to analyze EEG activity evoked by visual stimulation. This approach may augment the traditional VEP analysis. (2) Considering ensembles of EEG epochs as multidimensional spatial vectors evolving over time (rather than collections of time-domain signals) and evaluating the similarity between such vectors across different EEG epochs may result in a more accurate detection of colors that evoke greater responses of the visual system. To demonstrate its suitability, the developed analysis technique was applied to the EEG data that we previously collected from 19 participants with normal color vision, while exposing them to stimuli of continuously varying hue. (3) Orange/yellow and dark blue/violet colors generally aroused better-pronounced cortical responses. The selection of EEG channels allowed for assessing the activity that predominantly originates from specific cortical regions. With such channel selection, the strongest response to the hue was observed from Parieto-Temporal region of the right hemisphere. The statistical test-Kruskal-Wallis one-way analysis of variance-indicates that the distance evaluated for spatial EEG vectors at different post-stimulus latencies generally originate from different statistical distributions with a probability exceeding 99.9% (α = 0.001).