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BMJ Case Reports Apr 2021A 24-year-old woman was referred to us for an intracranial haemorrhage in the left temporal lobe caused by a ruptured cavernous malformation; the bleeding extended over...
A 24-year-old woman was referred to us for an intracranial haemorrhage in the left temporal lobe caused by a ruptured cavernous malformation; the bleeding extended over the left Heschl's gyrus and Wernicke area. On admission, the patient had global aphasia. A few days later, she spontaneously improved but remained with mild residual comprehensive dysphasia. She reported hearing, in her right ear, recently heard words, which is consistent with palinacousis. Auditory acuity testing was normal. EEG showed focal slowing in the left temporal region with no epileptiform activity. During awake surgery for resection of the cavernous malformation, stimulation of the superior temporal gyrus did not provoke palinacousis. The patient made good recovery with complete resolution of the aphasia and no recurrence of palinacousis. We aimed to review this phenomenon and to provide a systematic review of the current literature.
Topics: Adult; Brain Neoplasms; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Neoplasm Recurrence, Local; Temporal Lobe; Wakefulness; Young Adult
PubMed: 33849862
DOI: 10.1136/bcr-2020-236615 -
Scientific Reports Oct 2021A remarkable feature of the human brain is its ability to integrate information from the environment with internally generated content. The integration of top-down and... (Meta-Analysis)
Meta-Analysis
A remarkable feature of the human brain is its ability to integrate information from the environment with internally generated content. The integration of top-down and bottom-up processes during complex multi-modal human activities, however, is yet to be fully understood. Music provides an excellent model for understanding this since music listening leads to the urge to move, and music making entails both playing and listening at the same time (i.e., audio-motor coupling). Here, we conducted activation likelihood estimation (ALE) meta-analyses of 130 neuroimaging studies of music perception, production and imagery, with 2660 foci, 139 experiments, and 2516 participants. We found that music perception and production rely on auditory cortices and sensorimotor cortices, while music imagery recruits distinct parietal regions. This indicates that the brain requires different structures to process similar information which is made available either by an interaction with the environment (i.e., bottom-up) or by internally generated content (i.e., top-down).
Topics: Auditory Cortex; Auditory Perception; Brain; Brain Mapping; Humans; Imagination; Music
PubMed: 34675231
DOI: 10.1038/s41598-021-00139-3 -
NeuroImage. Clinical 2019Cross-modal occipital responses appear to be essential for nonvisual processing in individuals with early blindness. However, it is not clear whether the recruitment of... (Meta-Analysis)
Meta-Analysis
Cross-modal occipital responses appear to be essential for nonvisual processing in individuals with early blindness. However, it is not clear whether the recruitment of occipital regions depends on functional domain or sensory modality. The current study utilized a coordinate-based meta-analysis to identify the distinct brain regions involved in the functional domains of object, spatial/motion, and language processing and the common brain regions involved in both auditory and tactile modalities in individuals with early blindness. Following the PRISMA guidelines, a total of 55 studies were included in the meta-analysis. The specific analyses revealed the brain regions that are consistently recruited for each function, such as the dorsal fronto-parietal network for spatial function and ventral occipito-temporal network for object function. This is consistent with the literature, suggesting that the two visual streams are preserved in early blind individuals. The contrast analyses found specific activations in the left cuneus and lingual gyrus for language function. This finding is novel and suggests a reverse hierarchical organization of the visual cortex for early blind individuals. The conjunction analyses found common activations in the right middle temporal gyrus, right precuneus and a left parieto-occipital region. Clinically, this work contributes to visual rehabilitation in early blind individuals by revealing the function-dependent and sensory-independent networks during nonvisual processing.
Topics: Adult; Age of Onset; Blindness; Child; Child, Preschool; Humans; Multimodal Imaging; Neuroimaging; Occipital Lobe
PubMed: 31677587
DOI: 10.1016/j.nicl.2019.102041 -
Frontiers in Neuroanatomy 2022The plasticity of the central nervous system (CNS) allows the change of neuronal organization and function after environmental stimuli or adaptation after sensory...
The plasticity of the central nervous system (CNS) allows the change of neuronal organization and function after environmental stimuli or adaptation after sensory deprivation. The so-called critical period (CP) for neuroplasticity is the time window when each sensory brain region is more sensitive to changes and adaptations. This time window is usually different for each primary sensory area: somatosensory (S1), visual (V1), and auditory (A1). Several intrinsic mechanisms are also involved in the start and end of the CP for neuroplasticity; however, which is its duration in S1, VI, and A1? This systematic review evaluated studies on the determination of these time windows in small rodents. The careful study selection and methodological quality assessment indicated that the CP for neuroplasticity is different among the sensory areas, and the brain maps are influenced by environmental stimuli. Moreover, there is an overlap between the time windows of some sensory areas. Finally, the time window duration of the CP for neuroplasticity is predominant in S1.
PubMed: 35370567
DOI: 10.3389/fnana.2022.763245 -
Frontiers in Neurology 2022This meta-analysis evaluated the diagnostic value of intraoperative brainstem auditory evoked potential (BAEP) for predicting post-operative hearing loss.
OBJECTIVE
This meta-analysis evaluated the diagnostic value of intraoperative brainstem auditory evoked potential (BAEP) for predicting post-operative hearing loss.
METHODS
Research articles in MEDLINE, Embase, and Cochrane Library databases were searched and selected up to 20 January 2022, and data were extracted following a standard procedure. A diagnostic accuracy test meta-analysis was performed using a mixed-effect binary regression model.
RESULTS
A total of 693 patients from 15 studies were extracted. The change in intraoperative BAEP showed high sensitivity (0.95) but low specificity (0.37), with an area under the curve of 0.83. Diagnostic accuracy of the loss of potentials showed high sensitivity (0.82) and specificity (0.79). The area under the curve was 0.88. No factor was found to account for the heterogeneity of the results according to the meta-regression and subgroup analyses (all -values > 0.05).
CONCLUSIONS
Our results showed that the loss of BAEP has meaningful value for predicting hearing loss after vestibular schwannoma surgery. The change in BAEP is also important for its high sensitivity during hearing preservation surgery.
PubMed: 36588877
DOI: 10.3389/fneur.2022.1018324 -
Human Brain Mapping Feb 2022Noninvasive brain stimulation (NIBS) allows to actively and noninvasively modulate brain function. Aside from inhibiting specific processes, NIBS may also enhance...
Noninvasive brain stimulation (NIBS) allows to actively and noninvasively modulate brain function. Aside from inhibiting specific processes, NIBS may also enhance cognitive functions, which might be used for the prevention and intervention of learning disabilities such as dyslexia. However, despite the growing interest in modulating learning abilities, a comprehensive, up-to-date review synthesizing NIBS studies with dyslexics is missing. Here, we fill this gap and elucidate the potential of NIBS as treatment option in dyslexia. The findings of the 15 included studies suggest that repeated sessions of reading training combined with different NIBS protocols may induce long-lasting improvements of reading performance in child and adult dyslexics, opening promising avenues for future research. In particular, the "classical" reading areas seem to be most successfully modulated through NIBS, and facilitatory protocols can improve various reading-related subprocesses. Moreover, we emphasize the need to further explore the potential to modulate auditory cortex function as a preintervention and intervention approach for affected children, for example, to avoid the development of auditory and phonological difficulties at the core of dyslexia. Finally, we outline how future studies may increase our understanding of the neurobiological basis of NIBS-induced improvements in dyslexia.
Topics: Dyslexia; Humans; Transcranial Direct Current Stimulation; Transcranial Magnetic Stimulation
PubMed: 34716977
DOI: 10.1002/hbm.25700 -
Neural Regeneration Research Apr 2021Transcranial direct current stimulation (tDCS) has been reportedly beneficial for different neurodegenerative disorders. tDCS has been reported as a potential adjunctive...
Transcranial direct current stimulation (tDCS) has been reportedly beneficial for different neurodegenerative disorders. tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallucination (AVH). This study aims to review the effects of tDCS on AVH in patients with schizophrenia through combining the evidence from randomized clinical trials (RCTs). The databases of PsycINFO (2000-2019), PubMed (2000-2019), EMBASE (2000-2019), CINAHL (2000-2019), Web of Science (2000-2019), and Scopus (2000-2019) were systematically searched. The clinical trials with RCT design were selected for final analysis. A total of nine RCTs were eligible and included in the review. Nine RCTs were included in the final analysis. Among them, six RCTs reported a significant reduction of AVH after repeated sessions of tDCS, whereas three RCTs did not show any advantage of active tDCS over sham tDCS. The current studies showed an overall decrease of approximately 28% of AVH after active tDCS and 10% after sham tDCS. The tDCS protocols targeting the sensorimotor frontal-parietal network showed greater treatment effects compared with the protocols targeting other regions. In this regard, cathodal tDCS over the left temporoparietal area showed inhibitory effects on AVHs. The most effective tDCS protocol on AVHs was twice-daily sessions (2 mA, 20-minute duration) over 5 consecutive days (10 sessions) with the anode over the left dorsolateral prefrontal cortex and the cathode over the left temporal area. Some patient-specific and disease-specific factors such as young age, nonsmoking status, and higher frequencies of AVHs seemed to be the predictors of treatment response. Taken together, the results of tDCS as an alternative treatment option for AVH show controversy among current literatures, since not all studies were positive. However, the studies targeting the same site of the brain showed that the tDCS could be a promising treatment option to reduce AVH. Further RCTs, with larger sample sizes, should be conducted to reach a conclusion on the efficacy of tDCS for AVH and to develop an effective therapeutic protocol for clinical setting.
PubMed: 33063718
DOI: 10.4103/1673-5374.295315 -
Journal of Neurosurgery. Spine Mar 2017OBJECTIVE The goal of this study was to evaluate the efficacy of intraoperative transcranial motor evoked potential (TcMEP) monitoring in predicting an impending... (Review)
Review
OBJECTIVE The goal of this study was to evaluate the efficacy of intraoperative transcranial motor evoked potential (TcMEP) monitoring in predicting an impending neurological deficit during corrective spinal surgery for patients with idiopathic scoliosis (IS). METHODS The authors searched the PubMed and Web of Science database for relevant lists of retrieved reports and/or experiments published from January 1950 through October 2014 for studies on TcMEP monitoring use during IS surgery. The primary analysis of this review fit the operating characteristic into a hierarchical summary receiver operating characteristic curve model to determine the efficacy of intraoperative TcMEP-predicted change. RESULTS Twelve studies, with a total of 2102 patients with IS were included. Analysis found an observed incidence of neurological deficits of 1.38% (29/2102) in the sample population. Of the patients who sustained a neurological deficit, 82.8% (24/29) also had irreversible TcMEP change, whereas 17.2% (5/29) did not. The pooled analysis using the bivariate model showed TcMEP change with sensitivity (mean 91% [95% CI 34%-100%]) and specificity (mean 96% [95% CI 92-98%]). The diagnostic odds ratio indicated that it is 250 times more likely to observe significant TcMEP changes in patients who experience a new-onset motor deficit immediately after IS correction surgery (95% CI 11-5767). TcMEP monitoring showed high discriminant ability with an area under the curve of 0.98. CONCLUSIONS A patient with a new neurological deficit resulting from IS surgery was 250 times more likely to have changes in TcMEPs than a patient without new deficit. The authors' findings from 2102 operations in patients with IS show that TcMEP monitoring is a highly sensitive and specific test for detecting new spinal cord injuries in patients undergoing corrective spinal surgery for IS. They could not assess the value of TcMEP monitoring as a therapeutic adjunct owing to the limited data available and their study design.
Topics: Evoked Potentials, Motor; Evoked Potentials, Somatosensory; Monitoring, Intraoperative; Neurosurgical Procedures; Scoliosis; Spinal Cord Injuries
PubMed: 27935448
DOI: 10.3171/2015.7.SPINE15466 -
Critical Care (London, England) Aug 2018Electroencephalography (EEG) is a well-established tool for assessing brain function that is available at the bedside in the intensive care unit (ICU). This review aims...
BACKGROUND
Electroencephalography (EEG) is a well-established tool for assessing brain function that is available at the bedside in the intensive care unit (ICU). This review aims to discuss the relevance of electroencephalographic reactivity (EEG-R) in patients with impaired consciousness and to describe the neurophysiological mechanisms involved.
METHODS
We conducted a systematic search of the term "EEG reactivity and coma" using the PubMed database. The search encompassed articles published from inception to March 2018 and produced 202 articles, of which 42 were deemed relevant, assessing the importance of EEG-R in relationship to outcomes in patients with impaired consciousness, and were therefore included in this review.
RESULTS
Although definitions, characteristics and methods used to assess EEG-R are heterogeneous, several studies underline that a lack of EEG-R is associated with mortality and unfavorable outcome in patients with impaired consciousness. However, preserved EEG-R is linked to better odds of survival. Exploring EEG-R to nociceptive, auditory, and visual stimuli enables a noninvasive trimodal functional assessment of peripheral and central sensory ascending pathways that project to the brainstem, the thalamus and the cerebral cortex. A lack of EEG-R in patients with impaired consciousness may result from altered modulation of thalamocortical loop activity by afferent sensory input due to neural impairment. Assessing EEG-R is a valuable tool for the diagnosis and outcome prediction of severe brain dysfunction in critically ill patients.
CONCLUSIONS
This review emphasizes that whatever the etiology, patients with impaired consciousness featuring a reactive electroencephalogram are more likely to have a favorable outcome, whereas those with a nonreactive electroencephalogram are prone to having an unfavorable outcome. EEG-R is therefore a valuable prognostic parameter and warrants a rigorous assessment. However, current assessment methods are heterogeneous, and no consensus exists. Standardization of stimulation and interpretation methods is needed.
Topics: Brain; Consciousness Disorders; Electroencephalography; Humans; Prognosis
PubMed: 30071861
DOI: 10.1186/s13054-018-2104-z -
Frontiers in Psychiatry 2019Seed-based studies on resting-state functional connectivity (rsFC) in schizophrenia have shown disrupted connectivity involving a number of brain networks; however, the...
Seed-based studies on resting-state functional connectivity (rsFC) in schizophrenia have shown disrupted connectivity involving a number of brain networks; however, the results have been controversial. We conducted a meta-analysis based on independent component analysis (ICA) brain templates to evaluate dysconnectivity within resting-state brain networks in patients with schizophrenia. Seventy-six rsFC studies from 70 publications with 2,588 schizophrenia patients and 2,567 healthy controls (HCs) were included in the present meta-analysis. The locations and activation effects of significant intergroup comparisons were extracted and classified based on the ICA templates. Then, multilevel kernel density analysis was used to integrate the results and control bias. Compared with HCs, significant hypoconnectivities were observed between the seed regions and the areas in the auditory network (left insula), core network (right superior temporal cortex), default mode network (right medial prefrontal cortex, and left precuneus and anterior cingulate cortices), self-referential network (right superior temporal cortex), and somatomotor network (right precentral gyrus) in schizophrenia patients. No hyperconnectivity between the seed regions and any other areas within the networks was detected in patients, compared with the connectivity in HCs. Decreased rsFC within the self-referential network and default mode network might play fundamental roles in the malfunction of information processing, while the core network might act as a dysfunctional hub of regulation. Our meta-analysis is consistent with diffuse hypoconnectivities as a dysregulated brain network model of schizophrenia.
PubMed: 31354545
DOI: 10.3389/fpsyt.2019.00482