N1 Latency Research Articles

Acoustic change complex findings in mild and moderate sensorineural hearing loss

BackgroundAuditory electrophysiological tests of the cortex, which are processed in or close to the auditory cortex, are brain reactions to sound. A variation in a continuous stimulus causes the acoustic change complex potential (ACC), which is a wave following the P1-N1-P2 response.ObjectiveTo measure the amplitude and latency of different components of ACC in normal subjects and across individuals with mild and moderate degrees of sensorineural hearing loss (SNHL).Patients and methodsThe study includes 100 individuals with the age ranged from 10 to 50 years with different degrees of SNHL. The ACC was evoked by a change of second formant in the middle of ongoing steady-state synthetic, 3 formant vowels (ooee). The total duration was 500 ms. Changing occurred at 250 ms.ResultsThe SNHL subgroups showed statistically significantly longer P1 and N1 latencies. N1 and P2 amplitudes of ACC onset response were larger with a statistical significance as compared to controls. Post hoc analysis revealed no statistically significant difference between mild and moderate SNHL on ACC parameters. Age showed a significant negative correlation with ACC N1 and P2 latency, ACC P1 and N1 amplitude, and onset P2 latency. Onset response P1 latency was significantly higher in children than adults. Median ACC P1 amplitude significantly increased in children than adults.ConclusionACC is a reliable tool for testing the auditory cortex function of detecting difference in sounds presented that can be recorded readily in patients with mild and moderate SNHL.

Effects of Acetyl-L-Carnitine Administration on Auditory Evoked Potentials in Rats Exposed to Chronic Ethanol

These days, one of the biggest issues facing public health is chronic alcohol consumption. Prolonged alcohol intake has been associated with a number of illnesses, including pancreatitis, cerebrovascular illnesses, and liver damage. It is known that the endogenous molecule acetyl-L-carnitine (ALCAR) has neuroprotective properties. The objective of this study was to examine the impact of ALCAR on auditory evoked potentials (AEP) in a model of chronic alcoholism in rats. Four groups (n = 10) were randomly formed from 40 three-month-old albino Wistar rats: Sham (Sh), chronic ethanol (CE), ALCAR administered (ALCAR), and chronic ethanol+ALCAR (CE+ALCAR). The rats were administered either distilled water, ethanol, ALCAR, or ethanol+ALCAR via gavage for a duration of 4 weeks. AEP recordings were acquired from each rat upon the conclusion of the experiment period. The amplitudes of P1N1 and N1P2, in addition to the latencies of the P1, N1, and P2 peaks, were analyzed. Our findings showed that P1, N1, and P2 latencies were considerably prolonged in the CE group compared to the Sh group. Furthermore, the amplitudes of P1N1 and N1P2 exhibited an increase in the CE group relative to the Sh group, a decline in the CE+ALCAR group in comparison to the CE group, and a subsequent return to normal levels. Finally, our results demonstrated that, at the dose and duration used here, ALCAR normalized the increased neuronal activity but had no effect on the conduction velocity of the hearing signal.

Auditory Neural Responses and Communicative Functioning in Children With Microcephaly Related to Congenital Zika Syndrome.

Children with microcephaly exhibit neurodevelopmental delays and compromised communicative functioning, yielding challenges for clinical assessment and informed intervention. This study characterized auditory neural function and communication abilities in children with microcephaly due to congenital Zika syndrome (CZS). Click-evoked auditory brainstem responses (ABR) at fast and slow stimulation rates and natural speech-evoked cortical auditory evoked potentials (CAEP) were recorded in 25 Brazilian children with microcephaly related to CZS ( M age: 5.93 ± 0.62 years) and a comparison group of 25 healthy children ( M age: 5.59 ± 0.80 years) matched on age, sex, ethnicity, and socioeconomic status. Communication abilities in daily life were evaluated using caregiver reports on Vineland Adaptive Behavior Scales-3. Caregivers of children with microcephaly reported significantly lower than typical adaptive functioning in the communication and socialization domains. ABR wave I latency did not differ significantly between the groups, suggesting comparable peripheral auditory function. ABR wave V absolute latency and waves I-V interwave latency were significantly shorter in the microcephaly group for both ears and rates. CAEP analyses identified reduced N2 amplitudes in children with microcephaly as well as limited evidence of speech sound differentiation, evidenced mainly by the N2 response latency. Conversely, in the comparison group, speech sound differences were observed for both the P1 and N2 latencies. Exploratory analyses in the microcephaly group indicated that more adaptive communication was associated with greater speech sound differences in the P1 and N2 amplitudes. The trimester of virus exposure did not have an effect on the ABRs or CAEPs. Microcephaly related to CZS is associated with alterations in subcortical and cortical auditory neural function. Reduced ABR latencies differ from previous reports, possibly due to the older age of this cohort and careful assessment of peripheral auditory function. Cortical speech sound detection and differentiation are present but reduced in children with microcephaly. Associations between communication performance in daily life and CAEPs highlight the value of auditory evoked potentials in assessing clinical populations with significant neurodevelopmental disabilities.

Effects of hazard type and confidence level on hazard perception in young male drivers: an ERP study.

Hazard perception refers to a driver's ability to identify potential hazards on the road. Although studies have shown that overconfidence affects drivers' ability to perceive hazards, the neural processing of hazard perception in overconfident drivers under different hazard types has rarely been investigated. A mixed experimental design of 2 (hazard type: hazards, no hazards) × 2 (driver group: overconfident driver, control group) was used. A total of 120 images (60 with hazards and 60 without hazards) were presented to 25 overconfident drivers and 25 drivers in the control group. Reaction time, response accuracy, P200 (200-250 ms), and N2 (280-330 ms) components were measured via event-related potential (ERP) technology. Response times of overconfident drivers are slower than those of the control group regardless of hazard types. The P200 latency of overconfident drivers was longer than that of their peers in hazard situations, while the P200 latency was similar between the two groups in no-hazard situations. Although a significant interaction was found on the N2 amplitude, no significant differences were found between the two groups in both hazard and no-hazard situations. Overconfident drivers have worse hazard perception performance in hazard situations with slower reaction times and greater P200 latencies than their peers. More importantly, P200 amplitude and N2 amplitude are sensitive to hazard types, while P200 amplitude and N2 latency can discriminate between driver groups. The findings help understand the negative impact of overconfidence on young drivers and contribute to the development and training of hazard perception tests.

Identification and In Vivo Evaluation of Myelination Agent PIPE-3297, a Selective Kappa Opioid Receptor Agonist Devoid of β-Arrestin-2 Recruitment Efficacy.

Structure-activity relationship studies led to the discovery of PIPE-3297, a fully efficacious and selective kappa opioid receptor (KOR) agonist. PIPE-3297, a potent activator of G-protein signaling (GTPγS EC50 = 1.1 nM, 91% Emax), did not elicit a β-arrestin-2 recruitment functional response (Emax < 10%). Receptor occupancy experiments performed with the novel KOR radiotracer [3H]-PIPE-3113 revealed that subcutaneous (s.c.) administration of PIPE-3297 at 30 mg/kg in mice achieved 90% occupancy of the KOR in the CNS 1 h post dose. A single subcutaneous dose of PIPE-3297 in healthy mice produced a statistically significant increase of mature oligodendrocytes (P < 0.0001) in the KOR-enriched striatum, an effect that was not observed in animals predosed with the selective KOR antagonist norbinaltorphimine. An equivalent dose given to mice in an open-field activity-monitoring system revealed a small KOR-independent decrease in total locomotor activity versus vehicle measured between 60 and 75 min post dose. Daily doses of PIPE-3297 at both 3 and 30 mg/kg s.c. reduced the disease score in the mouse experimental autoimmune encephalomyelitis (EAE) model. Visually evoked potential (VEP) N1 latencies were also significantly improved versus vehicle in both dose groups, and latencies matched those of untreated animals. Taken together, these findings highlight the potential therapeutic value of functionally selective G-protein KOR agonists in demyelinating disease, which may avoid the sedating side effects typically associated with classical nonbiased KOR agonists.

Optimum stimulus for eliciting masseter vestibular-evoked myogenic potential: a comparative exploration with three different acoustic stimuli

ObjectiveTo compare the EMG rectified amplitude, absolute latencies, interpeak interval, and Interaural asymmetry parameters of masseter vestibular-evoked myogenic potential (mVEMP) elicited using clicks, 500 Hz tone bursts, and 500 Hz NB CE-chirps.MethodTwenty-five young healthy adults in the age range of 18–27 years participated for the study. mVEMP was recorded using three different acoustic stimuli i.e., clicks, 500 Hz tone bursts, and 500 Hz NB CE-chirps. mVEMP was recorded at an intensity of 125 dB peSPL with 5.1/s repetition rate. The potentials were recorded ipsilaterally using zygomatic electrode montage and were filtered between 0.1 and 3000 Hz. EMG rectification of the responses was made prior to analysis.ResultsThe latencies of P1 and N1 were significantly earlier for chirps then followed by click and tone bursts. The EMG rectified amplitude was significantly larger for the potentials obtained using chirps followed by tone bursts and then the clicks. Masseter VEMP obtained using chirps had significantly larger interpeak interval than tone bursts and clicks. The mean amplitude asymmetry ratio was greater in the potentials obtained using chirps than the other two stimuli.ConclusionThe present study reveals that 500 Hz NB CE-chirps tend to produce mVEMP with larger response amplitude and earlier latencies and thus are considered better and constructive stimuli compared to clicks and tone bursts.

Electrophysiological correlates of face and object perception: A comparative analysis of 2D laboratory and virtual reality conditions.

Human face perception is a specialized visual process with inherent social significance. The neural mechanisms reflecting this intricate cognitive process have evolved in spatially complex and emotionally rich environments. Previous research using VR to transfer an established face perception paradigm to realistic conditions has shown that the functional properties of face-sensitive neural correlates typically observed in the laboratory are attenuated outside the original modality. The present study builds on these results by comparing the perception of persons and objects under conventional laboratory (PC) and realistic conditions in VR. Adhering to established paradigms, the PC- and VR modalities both featured images of persons and cars alongside standard control images. To investigate the individual stages of realistic face processing, response times, the typical face-sensitive N170 component, and relevant subsequent components (L1, L2; pre-, post-response) were analyzed within and between modalities. The between-modality comparison of response times and component latencies revealed generally faster processing under realistic conditions. However, the obtained N170 latency and amplitude differences showed reduced discriminative capacity under realistic conditions during this early stage. These findings suggest that the effects commonly observed in the lab are specific to monitor-based presentations. Analyses of later and response-locked components showed specific neural mechanisms for identification and evaluation are employed when perceiving the stimuli under realistic conditions, reflected in discernible amplitude differences in response to faces and objects beyond the basic perceptual features. Conversely, the results do not provide evidence for comparable stimulus-specific perceptual processing pathways when viewing pictures of the stimuli under conventional laboratory conditions.

Effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy

BackgroundIt is reported that antiepileptic drugs have an effect on balance functions. The aim of the study was to evaluate and compare the effects of valproic acid and levetiracetam monotherapy on balance functions in patients with generalized epilepsy using objective test methods. MethodsThe study included 43 generalized epilepsy patients aged 18–60 years, including 20 patients receiving valproic acid monotherapy, 23 patients receiving levetiracetam monotherapy, and 25 healthy individuals as controls, in the Neurology Clinic of a university hospital in eastern Turkey. The demographic data form was filled out and the Video Head Impulse Test and Vestibular Evoked Myogenic Potentials test were performed. ResultsStatistically significant differences were obtained between the groups in lateral, posterior, and anterior semicircular canal gains and RALP and LARP asymmetry values in the V-HIT test (p < 0.05). Statistically significant differences were obtained between the groups in P1, N1 latency and asymmetry values in the C-VEMP test and in N1, P1 latency, amplitude, and asymmetry values in the o-VEMP test (p < 0.05). ConclusionValproic acid and levetiracetam may affect the vestibulocular and vestibulocolic reflex pathways negatively. In this cohort, valproic acid had more pronounced adverse effects on balance functions as compared to levetiracetam.

Measurement of Ocular Vestibular Evoked Myogenic Potentials: Nasion Reference Montage as an Alternative to the Clinical Standard Montage.

To compare two novel electrode montages for ocular, vestibular evoked myogenic potential using single-nasion reference electrodes with the clinical standard montage. Randomized crossover experiment. Tertiary referral center. Sixty healthy participants. Normal hearing and vestibular function were confirmed with an extensive test-battery. All ocular, vestibular evoked myogenic potential settings were measured with air-conducted tone bursts at 100-dB normal hearing level and a frequency of 500 Hz. Three electrode montages were measured in randomized order: the clinical standard montage ("S"), the nasion reference montage ("N"), and the nasion reference montage with a more lateral active electrode ("L"). Upgaze was standardized to 35 degrees. Detection rate, latency of N1 and P1, peak-to-peak amplitude of N1 and P1, signal-to-noise ratio (SNR), asymmetry ratio (AR), concordance of expert assessment, and reliability. All electrode montages showed detection rates greater than 90%. Latencies for "L" were shorter than for "S" and "N." Amplitudes and SNR for "S" and "N" were higher than for "L," whereas the values for "S" and "N" did not differ significantly. For AR, no significant differences between the montages were assessed. Concordance of experts ranged from 78% for "L" and 89.8% for "N." All montages provided excellent day-to-day reliability (intraclass correlation coefficient ≥0.9) for amplitudes and SNR. Montage N could be a useful alternative to the clinical standard montage: although results are roughly equivalent, montage N requires one less electrode to do so.

Standardized Treatment and Shortened Depression Course can Reduce Cognitive Impairment in Adolescents With Depression.

This study aimed to explore the influence of depression severity, disease course, treatment status, and other factors on cognitive function in adolescents with depressive disorders. Participants who met the inclusion criteria were enrolled in the study. Sociodemographic data of each participant were recorded, including age, sex, and family history of mental disorders. Zung's Self-Rating Depression Scale was used to assess depression status in adolescents. Moreover, P300 and mismatch negativity (MMN) were used to objectively evaluate the participants' cognitive function. Only 26.8% of the adolescents with depression received standard antidepressant treatment. The latencies of N2 (267.80±23.34 ms), P3 (357.71±32.09 ms), and MMN (212.10±15.61 ms) in the adolescent depression group were longer than those in the healthy control group (p<0.01). Further analysis revealed that the latency of MMN was extended with increased levels of depression in adolescents. The MMN latency was short in participants with depression receiving standardized treatment. Furthermore, the latency of MMN was positively correlated with the severity and duration of depression (correlation coefficients were 0.465 and 0.479, respectively) (p<0.01). Receiving standardized treatment and shortening the course of depression can reduce cognitive impairment in adolescents with depression.

Electrically evoked late latency response using single electrode stimulation and its relation to speech perception among paediatric cochlear implant users.

Aided auditory late latency response (LLR) serves as an objective tool for evaluating auditory cortical maturation following cochlear implantation in children. While aided LLR is commonly measured using sound-field acoustic stimulation, recording electrically evoked LLR (eLLR) offer distinct advantages, such as improved stimulus control and the capability for single electrode stimulation. Hence, the study aimed to compare eLLR responses with single electrode stimulation in the apical, middle, and basal regions and to evaluate their relationship with speech perception in paediatric cochlear implant (CI) recipients. eLLR responses with single electrode stimulation were measured in 27 paediatric unilateral CI users with an active recording electrode placed at Cz. The stimuli consisted of 36 msec biphasic pulse trains presented across three electrode sites (apical-E20, middle-E11, and basal-E03). eLLR responses were compared across these electrode sites, and the relationship between speech recognition scores in quiet and age at implantation with eLLR components was evaluated. eLLR responses were detected in 77 out of 81 tested electrodes of all participants combined (27 for apical, 26 for middle, and 24 for basal stimulation). There were no significant differences in P1, N1 latencies and P1 amplitude across electrode site. However, significantly larger N1 and P1-N1 amplitudes were observed for apical stimulations compared to basal stimulations. No differences in N1 amplitude were found between middle and apical stimulations, and the P1-N1 amplitude was significantly larger for middle compared to basal electrode stimulation, with no difference between the apical and middle electrodes stimulation. A moderate positive correlation was present between speech recognition scores in quiet and both N1, P1-N1 amplitudes for apical stimulation. Age at implantation was negatively correlated with N1 amplitude for the apical and P1-N1 amplitude for basal stimulation. eLLR responses could be elicited in majority of paediatric CI users across electrode sites. Variations in eLLR responses across electrode sites suggest disparities in auditory cortical maturation. The findings underscore the significance of the N1 biomarker in evaluating higher-order auditory cortical development. Therefore, utilizing eLLR with single electrode stimulation may serve as a valuable tool for assessing post-cochlear implantation maturational changes in paediatric populations.

THE IMPACT OF VACCINATION AGAINST SARS-CoV-2 INFECTION ON VESTIBULAR FUNCTION AND CENTRAL COMPENSATION

Objective: The aim of this study was to evaluate the effects of SARS-CoV-2 vaccines on vestibular system. In addition, in this study we aimed to investigate the possible protective effects of vaccination on the vestibular system in people who recovered Covid-19. Methods: Totally, 77 subjects were divided into four groups, and evaluated using computerized dynamic posturography (CDP), vestibular evoked myogenic potentials (VEMPs) and video head impulse test (v-HIT). The groups were as follows; Group 1; who had SARS-CoV-2 infection at least one year ago and have not been vaccinated at all. c Group 2; who had SARS-CoV-2 infection at least one year ago and were vaccinated 5 times (2 doses of Sinovac and 3 doses of Biontech). Group 3; who had no known SARS-CoV-2 infection, and were vaccinated 5 times (2 doses of Sinovac and 3 doses of Biontech). Group 4; who had no known SARS-CoV-2 infection, and have not been vaccinated at all. Results: The SOT values of (Covid-Vaccine-) group were better than the (Covid+Vaccine-) group (p=0.001), and no other significant difference was found between the groups (p&gt;0.05). The v-HIT gains of the groups were not significantly different (p&gt;0.05). On o-VEMPs, there was elongation in the N1 and P1 latencies in (Covid+Vaccine-) group compared to (Covid-Vaccine+) group. The amplitudes decreased in (Covid+Vaccine-) compared to (Covid-Vaccine-) (p&lt;0.05). According to c-VEMP results, vaccination lead to elongation in the P1 latencies and increased the P1-N1 amplitudes (p&lt;0.05). Conclusion: Both SARS-CoV-2 viral infection and vaccination may impact on vestibular system. The impact of vaccination seems on the saccule level. However, vaccination may limit or diminish the impact of SARS-CoV-2 on equilibrium, possibly by facilitating the central compensation.

The Effect of Simultaneous Contralateral White Noise Masking on Cortical Auditory Evoked Potentials Elicited by Speech Stimuli.

Introduction Noise obscures speech signal, causing auditory masking. The effects of this masking can be observed through the cortical auditory evoked potentials (CAEPs). White noise, in turn, has an effect on the auditory cortex, interfering, for example, with lexical decision making. Objective To analyze the effect of simultaneous masking by contralateral white noise on CAEPs elicited by speech stimuli. Methods Cross-sectional observational analytical study carried out with 15 participants of both sexes, who were submitted to CAEPs in two conditions: 1) without noise; 2) with white noise at 100 dBSPL intensity, contralaterally and simultaneously. To compare these conditions, the Student t test or the Wilcoxon test were used, depending on the sample normality. Differences with p values < 0.05 were considered significant. Results : When white noise was presented contralaterally and simultaneously to the CAEPs with speech stimulus, an increase in P1, N1 and P2 wave latencies was observed. P1 and P2 amplitudes and N1-P2 peak to peak amplitude also increased, unlike N1 amplitude, which decreased. The differences were significant for P1 and P2 wave latencies and for P2 wave amplitude. Conclusion The simultaneous masking effect was observed from the morphological alterations of the CAEPs with speech stimulus when white noise was presented in the contralateral ear. There was a significant increase in P1 and P2 wave latencies, as well as in P2 wave amplitude.

Late-onset of Labyrinthine Dysfunction in Chronic Brucella-induced Encephalitis

Brucellosis, caused by Brucella, dominates in the Middle East. Acute or chronic brucellosis can involve any organ system, and the involvement of the central nervous system leads to encephalitis, called neurobrucellosis (NB). We report a rare case from north India where a variant of Brucella caused NB led to progressive labyrinthine dysfunction; who developed vertigo, disequilibrium, and gradual progressive sensorineural (SN) hearing loss. Audiological tests pure-tone audiometry (PTA), otoacoustic emissions (OAE), stapedial muscle reflexes, auditory evoked brainstem responses (ABR), and vestibular evoked myogenic potentials (VEMPs) were conducted on the patients. PTA showed a bilateral profound SN hearing loss, an absent OAE, and ABR suggestive of cochlear dysfunction. The cervical and ocular VEMP showed delayed n1 and p1 latencies, suggesting superior and inferior nerve branch involvement. Vertigo or disequilibrium and SN hearing loss can be the late-onset manifestations of labyrinthine dysfunction in chronic Brucella-induced encephalitis.

Morphine exposure and prematurity affect flash visual evoked potentials in preterm infants

ObjectiveThe present study aimed to explore first the impact of perinatal risk factors on flash-VEP waves and morphology in a group of preterm infants studied at term equivalent age (TEA). Second, to correlate VEP morphology with neurological outcome at 2 years corrected age (CA). MethodsInfants with a gestational age (GA) at birth <32 weeks, without major brain injury, were enrolled. Multivariate regression analyses were performed, and the models were run separately for each dependent variable N2, P2, N3 latencies and P2 amplitude. Logistic regression was applied to study N4 component (present/absent) and VEP morphology (regular/irregular). The predictors were GA, bronchopulmonary dysplasia (BPD), postmenstrual age at VEP registration, cumulative morphine and fentanyl dose, and painful procedures. Lastly, linear regression models were performed to assess the relation between the Bayley-III cognitive and motor scores at 2 years CA and VEP morphology, in relation to GA, BPD, painful procedures and cumulative morphine dose. ResultsEighty infants were enrolled. Morphine was the predictor of N2 (R2 = 0.09, p = 0.006), P2 (R2 = 0.11, p = 0.002), and N3 (R2 = 0.13, p = 0.003) latencies. Younger GA was associated with lower amplitude (R2 = 0.05, p = 0.029). None of the independent variables predicted the presence of N4 component, nor VEP morphology in the logistic analysis. VEP morphology was not associated with cognitive and motor scores at 2 years. ConclusionsMorphine treatment and prematurity were risk factors for altered VEPs parameters at TEA. In our cohort VEP morphology did not predict neurological outcome. SignificanceMorphine administration should be evaluated according to potential risks and benefits, and dosage individually accustomed, according to pain and comfort scores, considering the possible risk for neurodevelopmental impairment.

Visual Event-Related Potentials under External Emotional Stimuli as Early Signs for Mild Cognitive Impairment.

Alzheimer's disease (AD) is a neurodegenerative disorder featured by progressive cognitive decline, which manifests in severe impairment of memory, attention, emotional processing and daily activities, leading to significant disability and social burden. Investigation on Mild Cognitive Impairment (MCI), the prodromal and transitional stage between normal aging and AD, serves as a key in diagnosing and slowing down the progression of AD. Numerous effects have been made up to date, however, the attentional mechanisms under different external emotion stimuli in MCI and AD are still unexplored in deep. To further explore the attentional mechanisms under different external emotion stimuli in both MCI and AD patients. In 51 healthy volunteers (Controls, 24 males and 27 females), 52 MCI (19 males and 33 females), and 47 AD (15 males and 32 females) patients, we administered the visual oddball event-related potentials (ERPs) under three types of external emotional stimuli: Neutral, Happiness and Sadness, in which the components N1, P2, N2 and P3 as well as the abnormal cortical activations corresponding to the significant ERP differences in the three groups were observed. Under all three external emotions, in AD patients, N2 and P3 latencies were significantly prolonged compared to both Controls and MCI. In addition, under Happiness, in MCI, P3 latencies were significantly delayed compared to Controls. Meanwhile, under both Happiness and Sadness, in AD patients, P3 amplitudes were significantly decreased compared to Controls and MCI, respectively. During N2 time window, under Neutral emotion, significant hypoactivation in the right superior temporal gyrus was found in AD patients compared to Controls, and under Happiness, the activation of the right inferior frontal gyrus was significantly attenuated in MCI compared to Controls. Under Sadness, in AD patients, the activation of the right superior frontal gyrus was significantly decreased compared to MCI. During P3 time window, under both Happiness and Sadness, when AD patients compared to MCI, the significantly attenuated activations were located in the right fusiform gyrus and the right middle occipital gyrus, respectively. Our results demonstrated visual attentional deficits under external emotional stimuli in both MCI and AD patients, highlighting the function of Happiness for early detecting MCI, in which the P3 latency and the hypoactivation of right inferior frontal gyrus during N2 time window can be early signs. The current study sheds further light of attentional mechanisms in MCI and AD patients, and indicates the value of emotional processing in the early detection of cognitive dysfunction.

Effects of Prebiotic Yeast Mannan on Gut Health and Sleep Quality in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Study.

Human gut health is closely related to sleep. We aimed to evaluate the efficacy of yeast mannan (YM) in improving bowel habits and sleep quality, along with metabolomics in fecal samples. A total of 40 healthy adults (age range, 22-64 years) with discomfort in defecation were enrolled and randomly allocated to receive either YM (n = 20; 1.1 g/day) or placebo (n = 20) for four weeks. Participants recorded their defecation habits throughout the test periods. Sleep electroencephalogram (EEG) recording using an EEG device and fecal sampling were performed pre- and post-treatment. The YM group significantly increased defecation frequency and stool volumes compared to the placebo group. After 4 weeks of treatment, the non-REM sleep stage 3 (N3) duration in the YM group was significantly higher than that in the placebo group. YM ingestion significantly lengthened total time in bed (TIB) and significantly shortened N3 latency compared to placebo intake during the trial. The metabolomics analysis found a total of 20 metabolite differences between the YM and placebo groups. As a result of stepwise linear regression, changes in fecal propionate and gamma-aminobutyric acid (GABA) levels were identified as the primary factors explaining changes in TIB and N3 latency, respectively. Our findings suggest that the prebiotic YM could be beneficial to gut health and sleep quality.

A Meta-Analysis of the Effectiveness of Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation as Therapy of Insomnia

Objective: Insomnia serves as the most common sleep disorder. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are amongst most popular treatment for insomnia. This research aimed to determine the comparative effectiveness of TMS and tDCS as therapies for insomnia.Methods: PubMed/MEDLINE, ScienceDirect, Google Scholar, ResearchGate, Wiley Library Online, and Neurona were used to search for randomized controlled trials (RCTs) comparing TMS/tDCS with sham group in insomnia. Meta-analysis was done to determine the effectiveness of TMS and tDCS as a therapy for insomnia. Weighted mean difference were computed and reported with its 95% CI. Heterogeneity was reported with I&lt;sup&gt;2&lt;/sup&gt;. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Subjective pooled-analysis was done using Mann-Whitney U test with p&lt;0.05.Results: From a total 1,000 publications, 15 studies were included, revealing varying types of insomnia as follows: 26.7% comorbid depression, 13.3% comorbid pain, 13.3% involving athletes, 13.3% primary insomnia, 6.7% due to medication, 6.7% comorbid polio, 6.7% comorbid Sjogren’s syndrome, 6.7% comorbid stroke, and 6.7% comorbid Parkinson’s disease. From 15 studies, four homogenous articles were made for pooled-analyses, which included two studies on TMS and two studies on tDCS in insomnia comorbid depression. tDCS improved sleep onset latency, N2, and REM latency better than sham. TMS (2.29, 95% CI: 1.82–2.76) was superior to sham in improving the subjective quality of sleep, and tDCS (1.05, 0.68–1.43) with p=0.121.Conclusion: No significant differences were found between TMS and tDCS as therapies for insomnia. Most RCTs studying TMS/tDCS in insomnia reported high comorbidity with depression.

Assessment of Cerebral Hypoxemia and Its Impact on Cognitive and Psychological Functions in Patients With Obstructive Sleep Apnea Syndrome

Background and Objective The precise pathophysiology of cognitive impedance and mental illness in obstructive sleep apnea (OSA) patients remains elusive. Therefore, there is a need for studies on novel diagnoses and therapeutic strategies for cognitive impairment in OSA patients. This work aimed to evaluate cerebral hypoxemia, its consequences on brain metabolism, and local and systemic inflammation, and their subsequent impact on cognitive and psychological functioning.Methods This cross-sectional case-control study was conducted on 30 eligible OSA patients and 20 age/sex-matched healthy controls. All the participants underwent one-night polysomnography, and cognitive evaluation was done using the Mini-Mental State Examination, Montreal Cognitive Assessment, Brief Kingston Standardized Cognitive Assessment, D2 Test of Consideration (to evaluate attention problems), and Wisconsin card sorting test. The psychiatric assessment included the Arabic form of the Hamilton Depression Rating Scale and Beck Depression Inventory-II. A radiology assessment was done using proton magnetic resonance spectroscopy. Neurophysiological assessment was done using the potential cortical (N20) latency and amplitude of somatosensory evoked potential. Laboratory examinations included serum levels of NF-κB, HMGB1, and HIF-1α.Results Polysomnography demonstrated noteworthy increase in the apnea-hypopnea index, respiratory disturbance index, arousal index, snoring index, and wake after sleep onset. It also showed diminished sleep efficiency, total sleep time, and SaO2 nadir in the OSA group. Neuropsychological scales demonstrated poor performance in global cognitive tests, particular cognitive domains impedance, and depression in the OSA group, with noteworthy differences within the group. Magnetic resonance spectroscopy highlighted that OSA patients had a noteworthy bilateral decrement in N-acetylaspartate (NAA) peak, creatine peak, and NAA/choline proportion and an increment in choline peak, lipid peak, lactate peak, choline/creatine proportion, and NAA/creatine proportion in the frontal white matter, hippocampus, and parieto-occipital cortex. Moreover. OSA patients had either missing or decreased amplitude and delayed latency of N20. There was a noteworthy rise of serum inflammatory marker NF-κB, HMGB1, and oxidative stress marker HIF-1α in OSA patients.Conclusions Chronic intermittent hypoxia with resulting amplified inflammatory and oxidative stress in OSA patients may affect brain metabolism; consequently, leading to cognitive and psychological dysfunctions.

The Processing of Phi-features in Sentences with Third-person Pronoun: An ERP Study in Turkish

The relationship between Person and Number features is often addressed in both theoretical and experimental studies. It is noteworthy that the discussion on how these features are processed has evolved over time towards how Person and Number features are structured in constructions with different persons (first person, second person, third person). While some studies state that Person and Number features can only be tested with third-person sentences (Manchini et al., 2011; Mancini et al., 2014), other studies state that these features can be tested with all person pronouns except R-expressions (regular noun phrases) (Ackema &amp; Neeleman, 2019). In the literature, it is noteworthy that the relationship between the processing of Person and Number features has been tested with first- and second-person pronouns and R-expressions, but there is no study testing the issue with third-person pronouns. The aim of this study was to investigate whether there is a difference in the processing of Person and Number features in sentences with third-person pronouns in Turkish using Event-related Brain Potentials (ERPs). In this study, three conditions, namely Grammatical, Person Mismatch and Number Mismatch, were presented visually in words to 33 participants. In the study, a widespread N400 component was observed in both the processing of the Person feature and the processing of the Number feature. It was found that there was no difference between the two features in the corresponding time window. However, in the next time window, a late N400 component was observed in the processing of the Number feature, while a positivity (P600) was observed in the processing of the Person feature. In this time window, there is a difference in the processing of the Person and Number features. In conclusion, this study found that there is a difference in the processing of the Person and Number features in sentences with third-person pronouns in Turkish. It is suggested that the P600 finding in the processing of the Person feature reflects the difficulty in processing this feature. It is suggested that the late N400 finding in the processing of the Number feature may be due to the load it imposes on the processing process due to the fact that the morphological appearance of the Number feature in verb conjugation is parallel to nominal pluralisation, and the greater demand on working memory as the resolution of the Number mismatch involves more alternatives than the Person mismatch.