N1 Latency Research Articles

Prolonged Visual Evoked Potential Latencies in Dogs Naturally Infected with Canine Distemper Virus

Canine distemper (CD) is a deadly, multi-system infection caused by a Morbillivirus. The canine distemper virus (CDV) frequently affects the nervous system with demyelinating leukoencephalitis, the most common neurological lesion. The disease has been linked to multiple sclerosis (MS) in humans due to similar clinical presentation and pathophysiological mechanisms. In MS, visual evoked potentials (VEPs) have been identified as a reliable marker for disease progression, enabling the early detection of clinically suspected lesions. The aim of this study was to determine if there are any abnormalities in VEP responses in dogs with neurological CD. Visual evoked potentials and electroretinogram (ERG) were recorded at both the cranial and spinal levels in dogs naturally infected with CDV and in healthy dogs. The results in the CDV-infected group revealed a bilateral increase in the latency of N1, P1, N2, P2, and N3 waves of the VEPs, without any alterations in their amplitudes. No significant differences were observed in the ERG between the groups. These results suggest that altered VEP responses could serve as an early diagnostic indicator of neurological damage caused by distemper. Therefore, conducting these studies could potentially aid in the detection of central nervous conduction disorders during the subclinical phases of the disease.

Reading Disability in Children: Exploring the N400 and its Associations with Set-For-Variability

ABSTRACT The N400 event-related potential (ERP), a marker of lexical-semantic processing, can assess the neural basis of reading difficulties. This study examines 1) semantic processes in typically developing (TD) children and children with reading disabilities (RD) using N400 and Set-for-Variability (SfV) profiles and 2) correlations between N400 and SfV. Fifty-one children read congruent and incongruent sentences during EEG. Results showed RD children lacked an N400 effect and had delayed SfV. A negative correlation between SfV and N400 latency in the RD group indicated distinct semantic processing delays in these children.

Study on the event-related potential in recognition of emotional words between typical “five-state personality”

Objective: To explore the event-related potential (ERP) differences of people with typical traditional Chinese medicine (TCM) “five-state personality” in the task of judging the emotional attributes (positive, neutral, and negative) of Chinese words. Methods: The “five-state personality test” was applied to screen the typical TCM “five-state personality”, and three groups were established including positive personality, negative personality, and atypical personality. The differences of electroencephalogram (EEG) components in the task of judging the emotional attributes of Chinese words were collected using ERPs. The 3 personality groups ×3 words with emotional attributes were analyzed by two-way analysis of variance (ANOVA). Results: The N1 and P300 components were induced successfully. The analysis on the mean values of corresponding electrodes in left frontal lobe, right frontal lobe, frontal lobe and parietal lobe showed that in the typical negative personality group, the absolute value of N1 amplitude was smaller in the prefrontal and frontal lobes, and the latency was shorter in the left frontal lobe, while in the typical positive personality group, the absolute value of N1 amplitude was larger in the left frontal lobe. In the prefrontal and frontal lobes, the N1 peak absolute value of negative words was higher and the latency was longer, and the N1 latency of neutral words was shorter. The N1 latency of positive words was shorter in the parietal lobe. In the right frontal and frontal lobes, the P300 peak of negative words was higher and the latency was longer, while the latency of positive words was longer in the parietal lobe. In addition, there was some interaction between personality groups and emotional attributes of words. Conclusion: When people with typical “five-state personality” judge the emotional attributes of words, the absolute value of N1 amplitude in left prefrontal lobe of typical positive personality group is high, while that of typical negative personality group was small and the latency is short. The P300 latency of negative words is longer in the right frontal and frontal lobes, and that of positive words is longer in the parietal lobes, with more significant difference in the positive personality group.

Assessment of Sacculocollic and Vestibulomasseteric Reflex Pathways in Individuals With Migraine and Vestibular Migraine.

The study's objective was to evaluate the functioning of sacculocollic and vestibulomasseteric reflex pathways in individuals with vestibular migraine and migraine. Seventy-five participants aged 18-50 years were selected for the study. Participants were divided into three groups. Group 1 consisted of 25 healthy individuals, Group 2 consisted of 25 migraine individuals, and Group 3 consisted of 25 individuals with vestibular migraine. Cervical vestibular-evoked myogenic potential (cVEMP) and masseter vestibular-evoked myogenic potential (mVEMP) were recorded using a 500-Hz tone burst stimulus presented at 125 dB peSPL for all participants. The cVEMP test results showed a delayed p13 and n23 latency for both migraine and vestibular migraine individuals when compared to healthy individuals. Also, the amplitude of the p13-n23 peak was reduced compared to healthy individuals in both migraine and vestibular migraine. Similarly, the mVEMP test results showed a delayed p11 and n21 latency for both migraine and vestibular migraine individuals. No difference was observed in the amplitude of the p11-n21 peak complex between the three groups. Spearman's rho correlation revealed no significant (p > .05) correlation between cervical and masseter VEMP latency and amplitude parameters between healthy, migraine, and vestibular migraine individuals. The results of the study are suggestive of the pathology of the sacullocollic and vestibulomasseteric reflex pathways in individuals with migraine and vestibular migraine. Individuals with migraine and vestibular migraine should undergo a detailed vestibular evaluation.

Vestibular Dysfunction in Euthyroid Children with Hashimoto's Thyroiditis.

A relationship exists between autoimmune thyroid disorders and vestibular dysfunction. This study aimed to analyze cervicalevoked myogenic potentials (cVEMP) and video head impulse test (vHIT) results between children with Hashimoto thyroiditis (HT) and healthy controls to determine vestibular end-organ problems. Thirty-six children with HT and 30 healthy subjects were recruited. The main inclusion criteria for the healthy group were the presence of normal thyroid function and no clinical history of vestibular problems. Each participant (both HT and healthy groups) was assessed using audiovestibular tests, cVEMP, and vHIT. There was no significant difference between the groups in terms of cVEMP (p1 and n1) latencies for both ears. There was no significant difference in cVEMP amplitudes (p1-n1 peak-to-peak) between the groups. There were statistically significant differences in the VOR gain of the right and left ears between the groups (P < .001, P < .001). When we considered lower cutoff value as 0.80 for VOR gain, 29 of 36 patients with HT (80.6%) had lower VOR gain scores. Only 1 of 30 healthy participants (3.3%) had a lower VOR gain score. This difference was statistically significant (P < .001). Subclinical vestibulopathy may occur in children with HT. The vHIT seems to be a valuable tool for identifying and screening preclinical vestibular pathologies in this patient group.

Face and face pareidolia in patients with temporal lobe epilepsy indicates different neural processing: an event-related potential study

BackgroundVisual perception of face images or face pareidolia can be evaluated with event-related potentials (ERP) for healthy subjects and patients with neurological conditions. In this study, we aimed to analyse event-related potential components such as P100, N100, N170, and vertex-positive potential (VPP) in response to face pareidolia perception in temporal lobe epilepsy (TLE) patients.MethodsERPs were recorded during the pareidolia test. Waveforms were analzyed and current source density (CSD) maps were generated.ResultsCSD profiles were shown to be interpretable when face and face pareidolia conditions. N100, P100, and N170 components showed larger amplitudes and longer latency in epilepsy patients in response to face pareidolia stimuli compared to real face images. However, the N170 component latency did not differ significantly between epilepsy patients and healthy participants, while the larger amplitude and longer latency of N100 and P100 responses were evoked in healthy patients.ConclusionsOur results indicate a difference in the neural mechanisms of processing real face information and pareidolia face-like information in TLE patients.

Comparison of Multifrequency Narrow-Band CE-Chirp and Tone Burst Evoked Cervical Vestibular Evoked Myogenic Potentials.

Cervical vestibular evoked myogenic potentials (cVEMPs) are inhibitory myogenic responses that have commonly been elicited using a variety of stimuli. Yet the comparison of the effects of multifrequency tone bursts and narrow-band Claus Elberling chirps (NB CE-chirps) on cVEMPs has never been studied in homogeneous age groups. The present study focused on comparing the effect of multifrequency NB CE-chirps and tone bursts on the various parameters of cVEMP responses in normal-hearing younger adults. A within-group study design was applied, and purposive sampling was utilized for the collection of the data sample. The present study involved the elicitation of NB CE-chirp and tone burst-evoked cVEMPs across four-octave frequencies in 25 normal-hearing younger adults. NB CE-chirp and tone burst evoked cVEMPs were found to have a 100% response rate for all frequencies except 4,000 Hz. Across frequencies, P1 and N1 latencies were seen to be significantly shorter for NB CE-chirps than tone bursts at 500 Hz and 1,000 Hz stimulation. No differences were seen in the P1N1 amplitudes and interaural asymmetry ratio between the two stimuli across all four-octave frequencies. Furthermore, we found a significantly higher number of ears tuned to NB CE-chirps than tone bursts at 500 Hz. Comparative differences in the latencies of cVEMP responses between and within stimuli could be due to the variation in stimuli duration. Also, the difference in amplitudes across stimulation frequencies might have resulted due to the predominance of saccular responses at lower mechanical resonance frequencies. Thus, the tuning was also seen at 500 Hz and was relatively higher for NB CE-chirps than tone bursts.

Preoperative variables affecting outcome of cochlear implant

BackgroundCochlear implants made a great impact in the management of severe-to-profound hearing loss in both children and adults. Its greatest impact is in helping children born with a profound hearing loss and implanted early to attend mainstream education and using spoken language to communicate. However, the final outcome in pediatric implantation is not predictable as there are large number of factors which will affect the outcome of cochlear implantation. Studying these determinants increases the ability of clinicians to offer educated preoperative prognosis and might potentially allow for manipulation of variables in an attempt to achieve the best possible outcome.ObjectiveThe aim of this study was to assess the preoperative factors affecting the audiological, speech, and language outcomes achieved by the recipients of cochlear implants.MethodologyA total of 39 children with severe-to-profound sensory neural hearing loss were implanted with cochlear implants. Children had received their implants before age of 5 years. Tests of receptive, expressive language quotient, aided cortical auditory-evoked potential using speech stimulus, aided free field audiometry, and aided speech reception thresholds were administered. Characteristics of the child and the family (age before implant and duration of implant use, cause of hearing loss, preimplant use of hearing aids and language therapy, and sociodemographic characteristics of their families) were the preoperative variables. These variables were considered predictors of audiological and language outcomes achieved by children and were determined using statistical analysis by univariate and multivariate analyses.ResultsAge of the studied children at time of cochlear implantation was statistically significant predictor for CI outcome as regard receptive language quotient and also for N1 latency. Hearing age of the studied children was a statistically significant predictor for CI outcome as regards P1 latency.ConclusionBased on our findings, two most important factors affecting outcome of cochlear implantation were the age at implantation and the hearing age. Other factors were important but did not affect the outcome significantly.

ERP biomarkers for go/no-go tasks to detect potential cognitive impairment in community-dwelling older adults

With an aging population, detecting cognitive dysfunction at an early stage is important. However, no current neurophysiological assessments examine brain activity status in community-dwelling older adults. Therefore, this study aimed to characterize event-related potential (ERP) during go/no-go tasks in older adults with potential cognitive impairment living in the community. The participants were 34 young adults and 46 older adults. They underwent a go/no-go task to measure ERP. The older adults were divided into two groups for analysis based on the results of the Japanese version of the Montreal Cognitive Assessment (MoCA-J): cognitively normal and cognitively impaired. N2 latency was significantly delayed in the cognitively impaired group compared to the cognitively normal and younger groups. Furthermore, the younger group exhibited a significant increase in P3 amplitude and shorter latency compared to both older adult groups. The results of the correlation analysis between ERP and neuropsychological test scores showed that N2 latency correlated with neuropsychological test scores. The results also suggested that receiver operating characteristic curve analysis can measure cognitive function. These results indicated that N2 latency reflected potential cognitive dysfunction in community-dwelling older adults. Furthermore, P3 amplitude may be useful in detecting age-related inhibitory function decline.

Mixed martial arts athletes demonstrate different brain vital sign profiles compared to matched controls at baseline.

We investigated objective brain vital signs derived from event-related potentials (ERPs) for mixed martial arts (MMA) athletes and matched controls (N = 24). Brain vital sign scans were acquired from 9 MMA athletes and 15 age-and sex-matched controls. Our analysis specifically compared differences in brain vital signs between MMA athletes and controls at baseline. We predicted that MMA athletes would show significant differences relative to controls due to their ongoing exposure to repetitive head impacts. Participants were scanned to extract three well-established ERPs: N100 for auditory sensation; P300 for basic attention; and N400 for cognitive processing. Scans were verified using automated reports, with N100, P300, and N400 amplitudes and latencies manually identified by a blinded reviewer. Brain vital signs were compared across groups with a Kruskal-Wallis H-test for independent samples, with FDR correction for multiple comparisons. We identified significant differences between MMA athletes and controls. Specifically, there were significant N400 amplitude reductions, indicating that exposure to repetitive head impacts in MMA may be associated with changes in brain function.

Short-latency afferent inhibition and its relationship to covert sensory and motor hand impairment in multiple sclerosis

ObjectiveTo investigate sensorimotor integration by quantifying short-latency afferent inhibition (SAI) in people with MS who experience manual dexterity problems compared to controls. Methods22 people with MS with self-reported manual dexterity problems and 10 sex and age-matched controls were assessed using various upper extremity clinical tests. SAI was assessed by a transcranial magnetic stimulation pulse over the primary motor cortex preceded by peripheral nerve stimulation to the median nerve at 6 interstimulus intervals 2 – 8 ms longer than individualized N20 latencies. ResultsAlthough within normal limits, persons with MS exhibited significantly slower Nine Hole Peg Test performance and pinch strength in the dominant hand. They also exhibited greater sensory impairment (monofilament test) in the dominant hand. Persons with MS showed significantly greater disinhibition of SAI in the dominant hand compared to controls, which was significantly correlated with weaker pinch strength. ConclusionReduced SAI in people with MS, particularly in the dominant hand, signifies disruptions in cortical cholinergic inhibitory activity and is associated with lower pinch strength. SignificanceEvaluating changes in SAI may offer insight into the disrupted cortical cholinergic inhibitory activity that contributes to sensorimotor disintegration, potentially advancing disease management in persons with MS.

Comparison of Air Conduction and Bone Conduction Masseter Vestibular Evoked Myogenic Potential Between Neurotypical Young Adults and Individuals With Conductive Hearing Loss.

Introduction Masseter vestibular evoked myogenic potential (mVEMP) is an acoustically evoked potential recorded from the masseter muscle. It is a recent tool in the vestibular assessment battery that checks the integrity of the vestibulomasseteric reflex pathway, specifically for saccular function. Need of the study There is a small pool of subjects with cervical spondylitis and anomalies in the eye muscle where cervical vestibular evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential (oVEMP) tests cannot be performed. In such conditions, mVEMP is considered an appropriate tool to assess the vestibular function. Bone conduction (BC) mVEMP assesses vestibular function in individuals with conductive hearing loss having a significant air-bone gap (ABG). Hence, it is essential to establish a comparative normal range of values for air conduction (AC) and BC mVEMP. Aim of the study The study aimed to evaluate the vestibulomasseteric reflex pathway using AC and BC mVEMP for click and 500 Hz tone burst stimuli in neurotypical young adults and compare it to individuals with conductive hearing loss. Method Ten neurotypical (20 ears) young adults and five (10 ears) individuals with conductive hearing loss in the age range of 15-40 years without vestibular complaints were recruited for the study. The AC and BC mVEMP were recorded monaurally using click and 500 Hz tone burst stimuli for all the participants. Results For neurotypical young adults, the mean latencies of P1 and N1 for AC and BC mVEMP using click were 13.87±1.86 ms and 19.78±2.14 ms and 13.79±2.06 ms and 21.30±1.48 ms, respectively. The P1 and N1 mean latencies for AC and BC mVEMP using 500 Hz tone burst were 14.90±1.50 ms and 21.03±1.30 ms and 14.18±0.95 ms and 19.75±1.71 ms, respectively. For individuals with conductive hearing loss, the P1 and N1 mean latencies for AC and BC mVEMP using click were 15.37±1.46 ms and 20.65±2.65 ms and 15.41±0.68 ms and 21.07±1.45 ms, respectively. AC mVEMP responses were absent for 500 Hz tone burst stimuli. The P1 and N1 mean latencies for BC mVEMP using 500 Hz tone burst stimuli were 14.96±0.6 ms and 22.72±1.42 ms, respectively. Conclusion AC mVEMP was absent for 500 Hz tone burst stimulus but present for click stimulus in individuals with conductive hearing loss as there was a larger ABG at the low frequencies than at the mid-high frequencies. BC mVEMP was present for click and 500 Hz tone burststimuli in all individuals with conductive hearing loss and latencies of P1 and N1 were similar to results obtained for neurotypical young adults and no significant difference was seen.

Effects of hazard type on the hazard perceptions of violation-involved and violation-free drivers: An ERP study

ObjectiveHazard perception, which is closely related to crash risk, is the ability to anticipate potential dangers on the road. This study aimed to investigate the effects of drivers’ previous traffic violation history on their neural processing of hazard perception under different hazard types. MethodsA mixed experimental design was employed, involving two groups of drivers (driver group: violation-involved, violation-free) and three types of images (no-hazard image, covert hazard image, overt hazard image). Twenty covert hazard images, 20 overt hazard images and 40 no-hazard images were randomly presented to 19 drivers with previous violation histories and 28 drivers without violations. The participants were asked to detect whether there was a hazardous situation in the images and press the keyboard quickly after detecting one. Response time, response accuracy and changes in the N1 (100–140 ms), N2 (250–300 ms) and P300 (300–400 ms) components of event-related potentials (ERP) were obtained and analysed. ResultsThe response time to the covert hazard images was significantly greater than that to the no-hazard and overt hazard images, and the lower accuracy also revealed that the covert hazard images were harder to detect than the no-hazard and overt hazard images. Under both overt and covert hazard images, the response time of violation-involved drivers was longer, and their accuracy was worse than that of violation-free drivers. The N1 latency of violation-involved drivers was significantly longer than that of violation-free drivers. The amplitude of N2 was significantly larger in the no-hazard image than in the covert and overt hazard images. The P300 amplitude was significantly greater in the overt hazard images than in the covert and no-hazard images. ConclusionViolation-involved drivers have poorer hazard perception abilities than violation-free drivers regardless of hazard type. N1 latency can differ from that of drivers with and without previous violations. These findings provide support for the development of hazard perception training systems for drivers who are prone to traffic violations.

Olfactory event-related potentials (OERPs) and trigeminal event-related potentials (TERPs) in subjects after Covid-19 infection: single-center prospective study.

Olfactory dysfunction (OD) is a common symptom associated with Covid-19. During the Covid-19 pandemic, the importance of psychophysical olfactory tests and electrophysiological olfactory assessment increased. The purpose of the study was to analyze the psychophysical olfactory tests and the post-covid curves of olfactory event-related potentials (OERPs) and trigeminal event-related potentials (TERPs). The prospective study included 98 subjects (62 females / 36 males). The average age was 42 years (range 21-84 years). Group I (n = 77) contained participants who had been infected with Covid-19. They were enrolled in the study at least 1 year after Covid-19. Group II (n = 21) was the healthy normosmic control group. In Group I, the OERPs of 18% participants were absent. Patients in Group I were statistically more likely to have an absence of OERPs (p = 0.036) than subjects in Group II. We did not detect a statistical difference in amplitudes and latencies of the OERPs between Group I and Group II. In Group I, N1 latency of the TERPs was significantly longer (p = 0.002) than in Group II. The amplitude of the N1-P2 interval of the TERPs was significantly lower (p = 0.025) in Group I than in Group II. According to the psychophysical Sniffin stick identification test, hyposmia was detected in 39% in Group I versus 0% in the control Group II. OD is a common post-covid symptom. The presence of OERPs is a significant prognostic factor for olfactory function after Covid 19. We detected a lower percentage of absence of OERPs after Covid-19 compared to the previously published studies of post-viral OD and post-infectious OD. For TERPs, we detected a longer N1 latency and a lower amplitude for the N1-P2 interval after Covid-19. OERPs and TERPs can be considered valid biomarkers to evaluate the progress of post-covid OD.

Balance Impairment in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis.

Balance weaknesses related to mobility and fall risk in patients with rheumatic diseases are well-known. Vestibular dysfunction could negatively contribute to the balance ability of this patient population. This study aims to investigate the effects of Rheumatoid Arthritis (RA) and Ankylosing Spondylitis (AS), among the most common rheumatic diseases, on postural balance related to vestibular function. Seventy-eight participants were grouped as RA (n=34, 43%), AS (n=24, 30.7%), and the control group consisted of healthy individuals (n=20, 25.6%). Cervical Vestibular Evoked Myogenic Potentials (cVEMP) test, which assesses the vestibular function objectively, Dizziness Handicap Inventory (DHI), which evaluates vertigo subjectively, and Berg Balance Scale (BBS) were performed. Different degrees of VEMP latency prolongations were found in the AS and RA groups. Right, and left ear N1 latencies were significantly longer in the AS group than in RA and control. Right ear P1 latency prolongation was statistically significant in the RA group. Amplitude asymmetry ratio (AAR) was found to be considerably higher in the RA and AS groups than in the control group (p<0.05). The mean BBS score in the AS group was below the fall risk score of 45. A negative statistically significant effect was observed between latency prolongation and BBS in AS groups. The abnormal VEMP findings in individuals with RA and AS shows inner ear vestibular system dysfunction. This vestibular impairment strictly contributes to their postural imbalance and requires a focused vestibular rehabilitation program for balance treatment.

Adiposity influences intraindividual variability in behavioral and neuroelectric indices of attentional inhibition.

While overweight or obesity are thought to affect over 70% of the US population, the effects of adiposity on neurocognitive efficiency and stability remain unclear. Intra-individual variability or trial-to-trial variability (IIV) could provide insights into the influence of adiposity on neurophysiological stability. However, previous work examining the association between adiposity and IIV of cognitive outcomes is limited. Thus, this study examined the association between whole-body fat (%BF) and central tendency and IIV metrics of behavioral performance and event-related potentials. Adults (n = 320; 19-64 yrs) completed the Flanker task to assess attentional inhibition with concurrent electroencephalogram recordings to examine the N2 and P3b components. In addition to central tendency outcomes typically reported (i.e., mean accuracy and reaction time [RT]), dispersion outcomes (e.g., standard deviation [SD] of RT, P3b latency, N2 latency, etc.) were also extracted. Upon controlling for age and sex, %BF was inversely associated with (congruent: β = -.18, p = .016; incongruent: β = -.23, p < .001) accuracy. Increasing %BF was related to greater RT SD (congruent: β = .13, p = .032; incongruent: β = .23, p < .001). Furthermore, increased %BF was associated with slower P3b latencies (congruent: β = .21, p = .003; incongruent: β = .18, p = .010), and greater incongruent N2 (β = .16, p = .017) and P3b (β = .16, p = .025) latency SD. These findings suggest adiposity exerts a generalized negative influence on attentional inhibition for both measures of central tendency and dispersion across behavioral and neuroelectric indices.

Alignment of behaviour and tDCS stimulation site induces maximum response: evidence from online tDCS and ERP

tDCS modulates the activity of the neuronal networks to induce the desired behavioural changes. Two factors determine its effectiveness- (1) whether the network being stimulated is relevant to the task, and (2) if there is a scope for improvement in behavioral performance. To explore this, both dorsal (sub-lexical) and ventral (lexical) reading networks were stimulated (20 min, 2 mA) in 25 healthy young volunteers. Participants performed two reading tasks with different levels of lexical involvement: word fragment completion tasks (WCT) and word association tasks (WAT), while event-related potentials (ERPs) were recorded simultaneously. The study used a within-subject design over three sessions, comparing various electrode montages targeting the dorsal pathway's left inferior parietal lobule or the ventral reading pathway's left middle temporal lobule, as well as sham stimulation. The impact of tDCS sessions (dorsal, ventral, & sham) and task type (WCT & WAT) on priming effects (primed vs. unprimed) of behavioral performance (accuracy and reaction times), and ERP parameters (N400 amplitudes and latencies) were statistically analyzed.It was found that tDCS modulated the performance of WAT only (a task with a lower priming effect). The failure to modulate WCT (larger priming effect) indicated that tDCS was effective for conditions with room for improvement compared to a task where performance has reached the ceiling. Ventral stimulation enhanced accuracy in the WAT condition and shortened the N400 latency of the priming effect. In contrast, dorsal stimulation delayed the priming effect reaction time in the WAT condition and enhanced the N400 amplitude. To conclude, enhancement in performance due to tDCS occurs when the network (ventral) being stimulated aligns with the cognitive demands of the task and there is a scope for improvement.

Cortical auditory evoked potentials in peripheral neuropathy

BackgroundCortical auditory evoked potentials (CAEPs) display both auditory processing and neurological activity in the auditory cortex. The purpose of this research is to evaluate the importance of CAEPs in identifying auditory processing disorders in patients with peripheral neuropathy (PN) in different pathologies. Sixty cases with PN of different pathologies represented the study group which was classified into two subgroups according to the underlying pathology of PN: those with either axonal PN (44 patients) and those with demyelinating PN (16 patients). The current study also included a control group of 40 healthy volunteers who did not have any peripheral or central auditory neurological disorders. CAEPs were recorded in both groups.ResultsThe study group’s CAEP response showed significantly delayed latencies than the control groups. Comparing the two study subgroups revealed that the axonal PN group had significant delayed latencies of N1 and P2 components in comparison to the demyelinating PN group.ConclusionCortical auditory evoked potentials can be used efficiently to diagnosis central auditory processing disorders in patients with PN. CAEP latencies can be employed alone or in conjunction with amplitudes; however, CAEP latencies are more significant than amplitudes for such purpose. Both demyelinating and axonal PN are associated with impaired auditory processing; however, axonal PN patients are more likely to be affected, suggesting that axonal PN has a significantly drastic effect on the central auditory nervous system.

Cognition in Patients with Spinocerebellar Ataxia 1 (SCA1) and 2 (SCA2): A Neurophysiological and Neuropsychological Approach.

Background/Objectives: Cognitive impairment in spinocerebellar ataxia patients has been reported since the early-disease stage. We aimed to assess cognitive differences in SCA1 and SCA2 patients. Methods: We performed neuropsychological (NPS) and neurophysiological (auditory event-related potentials, aERPs) assessments in 16 SCA1 and 18 SCA2 consecutive patients. Furthermore, clinical information (age at onset, disease duration, motor disability) was collected. Results: NPS tests yielded scores in the normal range in both groups but with lower scores in the Frontal Assessment Battery (p < 0.05) and Visual Analogue Test for Anosognosia for motor impairment (p < 0.05) in SCA1, and the Trail Making Test (p < 0.01), Raven's progressive matrices (p < 0.01), Stroop (p < 0.05), and emotion attribution tests (p < 0.05) in SCA2. aERPs showed lower N100 amplitude (p < 0.01) and prolonged N200 latency (p < 0.01) in SCA1 compared with SCA2. Clinically, SCA2 had more severe motor disability than SCA1 in the Assessment and Rating of Ataxia Scale. Conclusions: SCA2 showed more significant difficulties in attentional, visuospatial, and emotional function, and greater motor impairment. In contrast, SCA1 showed less cognitive flexibility/phasic ability, probably affected by a more severe degree of dysarthria. The same group revealed less neural activity during nonconscious attentional processing (N100-N200 data), suggesting greater involvement of sensory pathways in discriminating auditory stimuli. NFS did not correlate with NPS findings, implying an independent relationship. However, the specific role of the cerebellum and cerebellar symptoms in NPS test results deserves more focus.

The acoustic change complex evoked by location-change sounds in the elderly

Objective We have shown that the acoustic change complex (ACC) can be elicited by changing the horizontal sound location in young individuals. In this study, we aimed to evaluate the application of ACC within the elderly and its relationship with behavioural results. Design The minimum audible angle (MAA), as well as onset cortical auditory evoked potentials (onset-CAEPs) and ACC elicited by the stimuli of location-change white noise (±45 to ±2 degrees) were recorded. Latencies and amplitudes were analysed using repeated-measures ANOVA. Pearson correlation analysis was conducted to examine the relationship between ACC and MAA. Study sample Ten older adults with normal hearing (NH) and twenty with presbycusis. Results The ACC was effectively elicited with angular variations in elderly participants. The onset-CAEP N1 latency, ACC N1’-P2’ amplitude, and N1’ latency were all associated with the angle shifts, with the N1’ latency being the most predictive factor for angle discrimination. The consistency between MAA and ACC made them complementary for the clinical evaluation of sound localisation. Conclusions The utilisation of ACC, evoked by location-change sounds, presented a promising clinical objective measure for evaluating sound localisation abilities in the elderly.