- [Auditory evoked potentials in children with auditory neuropathy spectrum disorder]. [Journal Article]
- VOVestn Otorinolaringol 2018; 83(4):15-20
- The objective of the present study was to estimate peculiarities of the auditory brainstem evoked potentials (ABR), auditory steady-state responses (ASSR) and cortical auditory evoked potentials (CAE...
The objective of the present study was to estimate peculiarities of the auditory brainstem evoked potentials (ABR), auditory steady-state responses (ASSR) and cortical auditory evoked potentials (CAEP) in the children presenting with bilateral auditory neuropathy spectrum disorder (ANSD). The study included 100 patients with bilateral ANSD diagnosed based on the positive response of otoacoustic emissions (OAEs) and/or cochlear microphonic (CM) detection, while no synchronous neural activity was detected in the ABR test. Cochlear microphonic was the main clue for the ANSD diagnosing, because OAE was absent in both ears of 49 children. ABR testing revealed no response bilaterally in 72 cases (out of 100). In contrast to ABR, the ASSR thresholds were detectable at all the four main frequencies in both ears in 73 % of the cases (47 out of the 64 tested ones). Both ABR and ASSR in most cases were incomparable with the behavioral audiometric thresholds. 28 children underwent CAEP testing. In 7 cases out of 8 with mild hearing loss detectable CAEP were recorded. CAEP registration in l7 children making use of the hearing aids and in 3 children after cochlear implantation revealed, in the majority of the cases, the concordance between CAEP detectability with behavioral thresholds and rehabilitation outcomes with fairly good speech intelligibility. It is concluded that the ABR registration with CM evaluation is the most informative test for ANSD diagnosis. However, ABR as well as ASSR is useless for the estimation of the behavioral thresholds. The results of this study suggest that the presence or absence of CAEPs can provide some indication of the audibility of a speech sound in the children with ANSD; however this method requires further investigation.
- Extremely common radiographic finding of cochlear nerve deficiency among infants with prelingual single-sided deafness and its clinical implications. [Journal Article]
- IJInt J Pediatr Otorhinolaryngol 2018; 112:176-181
- CONCLUSIONS: The contribution of CND to prelingual SSD in Korean infants reached 100%, according to IAC MRI alone.
- Subsystem organization of axonal connections within and between the right and left cerebral cortex and cerebral nuclei (endbrain). [Journal Article]
- PNProc Natl Acad Sci U S A 2018 Jul 17; 115(29):E6910-E6919
- The endbrain (telencephalon) is at the rostral end of the central nervous system and is primarily responsible for supporting cognition and affect. Structurally, it consists of right and left cerebral...
The endbrain (telencephalon) is at the rostral end of the central nervous system and is primarily responsible for supporting cognition and affect. Structurally, it consists of right and left cerebral hemispheres, each parceled into multiple cortical and nuclear gray matter regions. The global network organization of axonal macroconnections between the 244 regions forming the endbrain was analyzed with a multiresolution consensus clustering (MRCC) method that provides a hierarchical description of community clustering (modules or subsystems) within the network. Experimental evidence was collated from the neuroanatomical literature for the existence of 10,002 of a possible 59,292 connections within the network, and they cluster into four top-level subsystems and 60 bottom-level subsystems arranged in a 50-level hierarchy. Two top-level subsystems are bihemispheric: One deals with auditory and visual information, and the other corresponds broadly to the default mode network. The other two top-level subsystems are bilaterally symmetrical, and each deals broadly with somatic and visceral information. Because the entire endbrain connection matrix was assembled from multiple subconnectomes, it was easy to show that the status of a region as a connectivity hub is not absolute but, instead, depends on the size and coverage of its anatomical neighborhood. It was also shown numerically that creating an ultradense connection matrix by converting all "absent" connections to a "very weak" connection weight has virtually no effect on the clustering hierarchy. The next logical step in this project is to complete the forebrain connectome by adding the thalamus and hypothalamus (together, the interbrain) to the endbrain analysis.
- [Preoperative diagnosis and evaluation of cochlear implantation in patients with cochlear nerve deficiency]. [Review]
- LCLin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2018; 32(10):794-798
- Cochlear nerve deficiency (CND) refers to a small or absent cochlear branch of the vestibulocochlear nerve (VCN) or cochlear nerve (CN). Congenitally deaf children with CND who received cochlear impl...
Cochlear nerve deficiency (CND) refers to a small or absent cochlear branch of the vestibulocochlear nerve (VCN) or cochlear nerve (CN). Congenitally deaf children with CND who received cochlear implants (CIs) generally exhibit poorer auditory performance than CI children without CND. It is important to confirm the integrity of the auditory pathway before surgery. High-resolution computed tomography (HRCT) and three-dimensional magnetic resonance imaging (3D MRI) are major techniques used to diagnosis CND. In this paper, we reviewed the methods of preoperative evaluation, cochlear nerve embryonic development, techniques for diagnosis and outcomes of cochlear implantation.
- The importance of central auditory evaluation in Friedreich's ataxia. [Journal Article]
- ANArq Neuropsiquiatr 2018; 76(3):170-176
- Objective To assess central auditory function in Friedreich's ataxia. Methods A cross-sectional, retrospective study was carried out. Thirty patients underwent the anamnesis, otorhinolaryngology exam...
Objective To assess central auditory function in Friedreich's ataxia. Methods A cross-sectional, retrospective study was carried out. Thirty patients underwent the anamnesis, otorhinolaryngology examination, pure tone audiometry, acoustic immittance measures and brainstem auditory evoked potential (BAEP) assessments. Results The observed alterations were: 43.3% in the pure tone audiometry, bilateral in 36.7%; 56.6% in the BAEP test, bilateral in 50%; and 46.6% in the acoustic immittance test. There was a significant difference (p < 0.05) in the comparison between the tests performed. Conclusion In the audiological screening, there was a prevalence of the descending audiometric configuration at the frequency of 4kHz, and absence of the acoustic reflex at the same frequency. In the BAEP test, there was a prevalence of an increase of the latencies in waves I, III and V, and in the intervals of interpeaks I-III, I-V and III-V. In 13.3% of the patients, wave V was absent, and all waves were absent in 3.3% of patients.
- Towards an objective test of chronic tinnitus: Properties of auditory cortical potentials evoked by silent gaps in tinnitus-like sounds. [Journal Article]
- HRHear Res 2018; 366:90-98
- A common method designed to identify if an animal hears tinnitus assumes that tinnitus "fills-in" silent gaps in background sound. This phenomenon has not been reliably demonstrated in humans. One te...
A common method designed to identify if an animal hears tinnitus assumes that tinnitus "fills-in" silent gaps in background sound. This phenomenon has not been reliably demonstrated in humans. One test of the gap-filling hypothesis would be to determine if gap-evoked cortical potentials are absent or attenuated when measured within background sound matched to the tinnitus sensation. However the tinnitus sensation is usually of low intensity and of high frequency, and it is unknown if cortical responses can be measured with such "weak" stimulus properties. Therefore the aim of the present study was to test the plausibility of observing these responses in the EEG in humans without tinnitus. Twelve non-tinnitus participants heard narrowband noises centered at sound frequencies of 5 or 10 kHz at sensation levels of either 5, 15, or 30 dB. Silent gaps of 20 ms duration were randomly inserted into noise stimuli, and cortical potentials evoked by these gaps were measured by 64-channel EEG. Gap-evoked cortical responses were statistically identifiable in all conditions for all but one participant. Responses were not significantly different between noise frequencies or levels. Results suggest that cortical responses can be measured when evoked by gaps in sounds that mirror acoustic properties of tinnitus. This design can validate the animal model and be used as a tinnitus diagnosis test in humans.
- Hearing impairment in MELAS: new prospective in clinical use of microRNA, a systematic review. [Review]
- OJOrphanet J Rare Dis 2018 Feb 21; 13(1):35
- CONCLUSIONS: We suggest that due to their accuracy and sensitivity, miRs might help monitor the progression of SNHL in patients with MELAS.
- Slow Accumulations of Neural Activities in Multiple Cortical Regions Precede Self-Initiation of Movement: An Event-Related fMRI Study. [Journal Article]
- EeNeuro 2017 Sep-Oct; 4(5)
- The neural processes underlying self-initiated behavior (behavior that is initiated without an external stimulus trigger) are not well understood. This event-related fMRI study investigated the neura...
The neural processes underlying self-initiated behavior (behavior that is initiated without an external stimulus trigger) are not well understood. This event-related fMRI study investigated the neural origins of self-initiated behaviors in humans, by identifying brain regions that increased in neural activities several seconds prior to self-initiated movements. Subjects performed a hand grasping task under two conditions: a free-timing and cued timing condition. The supplementary motor area (SMA) began to activate several seconds prior to self-initiated movement (accounting for hemodynamic delay), representing a potential blood oxygenation level-dependent (BOLD) signal correlate of the readiness potential (RP) on electroencephalogram (EEG), referred to here as "readiness BOLD signals." Significant readiness BOLD signals were also observed in the right frontoparietal areas, precuneus, and insula, all of which are known to contribute to internally-generated behaviors, but with no prior evidence for such early and slow accumulation of neural activities. Moreover, visual and auditory cortices also exhibited clear readiness BOLD signals with similar early onsets, even absent external stimulation. Slow accumulation of neural activities throughout distributed cortical areas, including sensory, association, and motor cortices, underlies the generation of self-initiated behaviors. These findings warrant reconsideration of the prevailing view that the SMA or some other specific locus in frontoparietal cortex serves as the ultimate neural origin of self-initiated movement.
- Hallucinations in borderline personality disorder: Prevalence, characteristics and associations with comorbid symptoms and disorders. [Journal Article]
- SRSci Rep 2017 Oct 24; 7(1):13920
- To establish the point prevalence of hallucinations in borderline personality disorder (BPD), telephone interviews were conducted with 324 outpatients diagnosed with BPD. Then a subgroup (n = 98) was...
To establish the point prevalence of hallucinations in borderline personality disorder (BPD), telephone interviews were conducted with 324 outpatients diagnosed with BPD. Then a subgroup (n = 98) was interviewed in person to investigate the co-occurrence of these phenomena with other psychotic symptoms, comorbid psychiatric disorders, prior childhood adversities, and adult life stressors. For hallucinations in general a point prevalence of 43% was found, with rates for hallucinations in separate sensory modalities ranging from 8-21%. Auditory verbal hallucinations consisted mostly of verbal abuse and were generally experienced as distressing. A significant association was found between the severity of hallucinations on the one hand, and delusions and unusual thought content on the other; this association was absent for negative symptoms and disorganization. The presence of hallucinations also correlated with the number of comorbid psychiatric disorders, and with posttraumatic stress disorder (PTSD) specifically. Childhood emotional abuse and adult life stressors were also associated with hallucinations. The latter three associations suggest that patients with BPD might have an etiological mechanism in common with other patient/nonpatient groups who experience hallucinations. Based on these findings, we advise to treat PTSD and hallucinations when found to be present in patients with BPD.
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- Disrupted cholinergic modulation can underlie abnormal gamma rhythms in schizophrenia and auditory hallucination. [Journal Article]
- JCJ Comput Neurosci 2017; 43(3):173-187
- The pathophysiology of auditory hallucination, a common symptom of schizophrenia, has yet been understood, but during auditory hallucination, primary auditory cortex (A1) shows paradoxical responses....
The pathophysiology of auditory hallucination, a common symptom of schizophrenia, has yet been understood, but during auditory hallucination, primary auditory cortex (A1) shows paradoxical responses. When auditory stimuli are absent, A1 becomes hyperactive, while A1 responses to auditory stimuli are reduced. Such activation pattern of A1 responses during auditory hallucination is consistent with aberrant gamma rhythms in schizophrenia observed during auditory tasks, raising the possibility that the pathology underlying abnormal gamma rhythms can account for auditory hallucination. Moreover, A1 receives top-down signals in the gamma frequency band from an adjacent association area (Par2), and cholinergic modulation regulates interactions between A1 and Par2. In this study, we utilized a computational model of A1 to ask if disrupted cholinergic modulation could underlie abnormal gamma rhythms in schizophrenia. Furthermore, based on our simulation results, we propose potential pathology by which A1 can directly contribute to auditory hallucination.