Middle Latency Research Articles

Evaluation of auditory middle latency response during the menstrual cycle

Aim: The hormone levels during the menstrual cycle, directly and indirectly, affect the hearing system. In our study, it was aimed to examine the effects of changing hormone levels during the menstrual cycle on auditory middle latency responses in healthy individuals with different stimuli types and the psychosomatic effects of premenstrual complaints on auditory performance. Methods: In the study, 20 healthy women aged 18-35 years, with regular menstrual cycles and no auditory or vestibular complaints were evaluated for auditory middle latency responses with click and level-specific (LS) CE-Chirp® stimuli during the menstruation period of the follicular phase (1-5 day, menstrual phase), the ovulation phase (14-17 day) and the luteal phase (21-28 day). To evaluate the effect of premenstrual complaints on auditory performance, the participants were asked 5 questions. Results: In the auditory middle latency assessment with click stimuli, a statistically larger Na-Pa amplitude was obtained in the menstruation phase compared to the ovulation phase in both ears. In the auditory middle latency evaluation with LS CE-Chirp® stimulus, statistically shortened Nb latencies were obtained in the right ear in the menstruation phase compared to the ovulation phase. Conclusion: Although the clear effect of changing gonadal hormone levels on auditory evoked middle latency responses could not be determined, the findings show that neural transmission increases in the menstrual phase when the estrogen level is low. Click stimulus is more sensitive to hormonal changes, and the use of click stimulus has been recommended in the later side of lesion studies. In our study, no psychosomatic effect of complaints in the premenstrual period on auditory performance was observed.

Investigating the Feasibility of Gap Prepulse Inhibition by Auditory Middle Latency Responses in Healthy Subjects

Background and Aim: Gap Prepulse Inhibition (GPI) is a type of Prepulse Inhibition (PPI) in which a gap is used as a prepulse. This study was conducted to investigate the silence gap effect on Auditory Middle Latency Response (AMLR) inhibition in normal subjects. Methods: In this study, 25 participants with normal hearing and no history of tinnitus were included. AMLR was recorded in response to stimuli with gap and without gap in two background noises of 2 and 8 kHz at two electrode locations Fz and Cz and then, gap prepulse inhibition for Na-Pa, Pa-Nb, Nb-Pb and Pb-Nc amplitude with Use of responses to stimuli with and without gap was calculated. Results: The results showed that the mean amplitudes of all four AMLR indices decreased in response to the stimuli with gap and this decrease was more and statistically significant in 8 kHz background noise (p≤0.001). Conclusion: According to the results of this study, it seems that in future studies, PPI of Na-Pa and Pb-Nc amplitudes can be used as main indicators and PPI of Pa-Nb and Nb-Pb amplitudes as alternative indicators in the PPI paradigm in tinnitus diagnosis. Keywords: Prepulse inhibition; tinnitus; auditory middle latency responses

Therapeutic Function of Liraglutide for Mitigation of Blast-Induced Hearing Damage: An Initial Investigation in Animal Model of Chinchilla.

Auditory injuries induced by repeated exposures to blasts reduce the operational performance capability and the life quality of military personnel. The treatment for blast-induced progressive hearing damage is lacking. We have recently investigated the therapeutic function of liraglutide, a glucagon-like peptide-1 receptor agonist, to mitigate blast-induced hearing damage in the animal model of chinchilla, under different blast intensities, wearing earplugs (EPs) or not during blasts, and drug-treatment plan. The goal of this study was to investigate the therapeutical function of liraglutide by comparing the results obtained under different conditions. Previous studies on chinchillas from two under-blast ear conditions (EP/open), two blast plans (G1: 6 blasts at 3-5 psi or G2:3 blasts at 15-25 psi), and three treatment plans (blast control, pre-blast drug treatment, and post-blast drug treatment) were summarized. The auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) recorded within 14 days after the blasts were used. Statistical analysis was performed to evaluate the effect of liraglutide under different conditions. ABR threshold shifts indicated that the conditions of the EP and open ears were substantially different. Results from EP chinchillas indicated that the pre-blast treatment reduced the acute ABR threshold elevation on the day of blasts, and the significance of such an effect increased with the blast level. Liraglutide-treated open chinchillas showed lower ABR threshold shifts at the later stage of the experiment regardless of the blast levels. The DPOAE was less damaged after G2 blasts compared to G1 when pre-blast liraglutide was administrated. Lower post-blast MLR amplitudes were observed in the pre-blast treatment groups. This study indicated that the liraglutide mitigated the blast-induced auditory injuries. In EP ears, the pre-blast administration of liraglutide reduced the severity of blast-induced acute damage in ears with EP protection, especially under G2. In animals with open ears, the effect of liraglutide on the restoration of hearing increased with time. The liraglutide potentially benefits post-blast hearing through multiple approaches with different mechanics.

Facilitation of Early and Middle Latency SEP after tDCS of M1: No Evidence of Primary Somatosensory Homeostatic Plasticity

Homeostatic plasticity is a mechanism that stabilizes cortical excitability within a physiological range. Most homeostatic plasticity protocols have primed and tested the homeostatic response of the primary motor cortex (M1). This study investigated if a homeostatic response could be recorded from the primary sensory cortex (S1) after inducing homeostatic plasticity in M1. In 31 healthy participants, homeostatic plasticity was induced over M1 with a priming and testing block of transcranial direct current stimulation (tDCS) in two different sessions (anodal and cathodal). S1 excitability was assessed by early (N20, P25) and middle-latency (N33-P45) somatosensory evoked potentials (SEP) extracted from 4 electrodes (CP5, CP3, P5, P3). Baseline and post-measures (post-priming, 0-min, 10-min, and 20-min after homeostatic induction) were taken. Anodal M1 homeostatic plasticity induction significantly facilitated the N20-P25, P45 peak, and N33-P45 early SEP components up to 20-min post-induction, without any indication of a homeostatic response (i.e., reduced SEP). Cathodal homeostatic induction did not induce any significant effect on early or middle latency SEPs. M1 homeostatic plasticity induction by anodal stimulation protocol to the primary motor cortex did not induce a homeostatic response in SEPs.

Middle Latency Auditory Evoked Response during High-frequency Yoga Breathing, Breath Awareness, and Quiet Rest.

Yoga breathing influences cortical activity and, hence, cortico-efferent sensory activity. Previously, slow yoga breathing influenced the components of mid-latency auditory evoked potentials. The present study aimed to compare middle latency auditory evoked potentials (MLAEPs) recorded during (i) High-frequency yoga breathing (HFYB), (ii) Breath awareness (BAW), and (iii) Quiet rest (QR) as a control in experienced yoga practitioners. The MLAEPs were recorded before, during, and after the practice of HFYB compared to an equal duration of BAW and QR in 22 university students whose ages ranged from 18 to 28 years, recorded from the vertex referenced to linked earlobes and the ground electrode on forehead. The peak amplitude of the Pa wave was significantly increased during HFYB compared to before HFYB (repeated measures ANOVA, post hoc analysis with least significant difference, P < 0.05). During BAW, the peak amplitude of the Na wave was significantly increased compared to before BAW (P < 0.05). During QR, the peak latency of "Pa" and "Nb" waves was significantly increased compared to before QR (P < 0.01). The findings suggest that changes in MLAEPs during HFYB, BAW, and QR were different and distinct. Both interventional sessions appear to increase the recruitment of neural resources in the primary auditory cortex, whereas QR appears to slow transmission within the thalamic reticular projection to the cortex. Generalizing the findings is restricted by the sample being confined to male experienced practitioners of yoga breathing.

Phenotypic spectrum of tinnitus patients bearing rare ANK2 gene variants

PurposeTo describe the clinical, audiological, and psychometric features observed in patients with chronic tinnitus and rare variants in the ANK2 gene.MethodsWe report a case series of 12 patients with chronic tinnitus and heterozygous variants in the ANK2 gene. Tinnitus phenotyping included audiological (standard and high-frequency audiometry, Auditory Brainstem Responses (ABR) and Auditory Middle Latency Responses (AMLR)), psychoacoustic and psychometric assessment by a Visual Analog Scale (VAS) for tinnitus annoyance, the Tinnitus Handicap Inventory (THI), the test on Hypersensitivity to Sound (THS-GÜF), the Patient Health Questionnaire (PHQ-9), the Hospital Anxiety and Depression Scale (HADS) and the Montreal Cognitive Assessment (MoCA).ResultsAll patients reported a persistent, unilateral noise-type tinnitus, mainly described as white noise or narrowband noise. Seven patients (58%) were considered to have extreme phenotype (THI score > 76), and all patients reported some degree of hyperacusis (THS-GÜF score > 18 in 75% of patients). Seven patients scored MoCA < 26, regardless of the age reported, suggesting a mild cognitive disorder. ABR showed no significant differences in latencies and amplitudes between ears with or without tinnitus. Similarly, the latencies of Pa, Pb waves, and NaPa complex in the AMLR did not differ based on the presence of tinnitus. However, there were statistical differences in the amplitudes of Pa waves in AMLR, with significantly greater amplitudes observed in ears with tinnitus.ConclusionPatients with ANK2 variants and severe tinnitus exhibit an endophenotype featuring hyperacusis, persistent noise-like tinnitus, high-frequency hearing loss, and decreased amplitudes in AMLR. However, anxiety, depression, and cognitive symptoms vary among individuals.

My Perspective: Auditory Evoked Potentials Using Speech

Purpose: The purpose of this tutorial is to clarify the use of speech sounds as stimuli for auditory evoked potentials and how these might contribute to our understanding of speech, language, learning, and hearing disorders. Speech-evoked auditory brainstem responses (ABRs), auditory steady-state responses, auditory middle latency responses, mismatch negativity, P300, cortical onset responses, and the acoustic change complex are reviewed. Method: The author drew upon her scholarship in this area from over 4 decades of research and teaching to summarize the major findings when using speech stimuli to evoke auditory potentials that have been used in clinical contexts. Results: Speech-evoked auditory potentials contribute to our understanding of how the brain processes the acoustic features of speech sounds, providing information that is complementary to psychophysical tests. When psychophysical tests cannot be performed owing to neurodevelopmental immaturity or disability, or cognitive disability, speech-evoked auditory potentials may be used to estimate the benefit of amplification or implantation for speech, language, and hearing. Conclusions: The benefit of using auditory evoked potentials for evaluation is that they provide insight into the brain mechanisms underlying hearing and listening disorders that audiologists aim to treat. While we can use the known correlations between perceptual and electrophysiological responses for “cross-checking” our evaluation results, examining when discrepancies occur is also especially meaningful. For example, the complex ABR reveals subcortical issues in temporal processing that would not be evident in ABRs to clicks or tone bursts, nor in behavioral testing. P300 can document slower neural processing of speech stimuli that may be relevant to the rehabilitation of older adults, even when word recognition scores appear to be congruent with the pure-tone audiogram. In these ways, auditory evoked potentials for speech provide audiologists with tools for demonstrating to clients how their brain responds to speech and opening the conversation for rehabilitation.

Habituation disorders in auditory middle latency response of persistent postural-perceptual dizziness patients.

To study habituation disorders in auditory middle latency response (AMLR) to repetitive stimuli of persistent postural-perceptual dizziness (PPPD) patients. Twenty-eight PPPD (10 men and 18 women, mean 59.5 years of age, 26-81 years of age) were enrolled. For comparison, data of 13 definite vestibular migraine (VM) patients (3 men, 10 women, mean age 45.5), 13 definite unilateral Meniere's disease (MD) patients (2 men, 11 women, mean age 50.6), and 8 healthy control (HC) subjects (2 men, 6 women, mean age 37.1) in the previous study were utilized. The electrodes were placed on the vertex and the spinal process of the fifth cervical vertebra. Clicks (0.1 msec, 70 dB nHL) were binaurally presented and averaged (800 times). Averaged responses were divided into 4 sets (S1 to S4) according to the temporal order. As peaks, Na, and Pa were identified, and relative Na-Pa amplitudes in S2-S4 to S1 were analyzed. The mean relative amplitude of PPPD patients showed lack of habituation (potentiation) as shown in VM patients, although the extent of potentiation was weaker than VM. Comparison of relative S4 amplitudes showed significant differences among the 4 groups (p = 0.0013 one-way ANOVA), Multiple comparison revealed significant differences between PPPD and MD (p = 0.0337 Dunnet's test). PPPD patients showed lack of habituation (potentiation) of Na-Pa amplitude in AMLR to repetitive stimuli. Lack of habituation (potentiation) might be associated with sensory processing disorders in PPPD.

Comprehensive behavioral and physiologic assessment of peripheral and central auditory function in individuals with mild traumatic brain injury

Auditory complaints are frequently reported by individuals with mild traumatic brain injury (mTBI) yet remain difficult to detect in the absence of clinically significant hearing loss. This highlights a growing need to identify sensitive indices of auditory-related mTBI pathophysiology beyond pure-tone thresholds for improved hearing healthcare diagnosis and treatment. Given the heterogeneity of mTBI etiology and the diverse peripheral and central processes required for normal auditory function, the present study sought to determine the audiologic assessments sensitive to mTBI pathophysiology at the group level using a well-rounded test battery of both peripheral and central auditory system function. This test battery included pure-tone detection thresholds, word understanding in quiet, sentence understanding in noise, distortion product otoacoustic emissions (DPOAEs), middle-ear muscle reflexes (MEMRs), and auditory evoked potentials (AEPs), including auditory brainstem responses (ABRs), middle latency responses (MLRs), and late latency responses (LLRs). Each participant also received magnetic resonance imaging (MRI). Compared to the control group, we found that individuals with mTBI had reduced DPOAE amplitudes that revealed a compound effect of age, elevated MEMR thresholds for an ipsilateral broadband noise elicitor, longer ABR Wave I latencies for click and 4 kHz tone burst elicitors, longer ABR Wave III latencies for 4 kHz tone bursts, larger MLR Na and Nb amplitudes, smaller MLR Pb amplitudes, longer MLR Pa latencies, and smaller LLR N1 amplitudes for older individuals with mTBI. Further, mTBI individuals with combined hearing difficulty and noise sensitivity had a greater number of deficits on thalamic and cortical AEP measures compared to those with only one/no self-reported auditory symptoms. This finding was corroborated with MRI, which revealed significant structural differences in the auditory cortical areas of mTBI participants who reported combined hearing difficulty and noise sensitivity, including an enlargement of left transverse temporal gyrus (TTG) and bilateral planum polare (PP). These findings highlight the need for continued investigations toward identifying individualized audiologic assessments and treatments that are sensitive to mTBI pathophysiology.

Evoked Potentials by Tone Burst on the Auditory Cortices in Cats -Comparison of Off Responses in Awake and Anesthetized Conditions.

Auditory Brainstem Response (ABR) recording in awake is essential to detect off-responses. This study clarified whether after-termination responses on ABR were offset responses, off-responses or a mixture of the two. Evoked potentials in the auditory cortex of cats in response to tone burst stimuli were recorded, and off responses were examined with chronically implanted electrodes. When the fall time at the end of sound stimuli was 5ms or longer, the amplitude of click responses was extremely small. Under this condition, evoked potentials in response to two types of tone bursts (long and short) were recorded.By calculating the differences in evoked potentials between the two-tone bursts, off responses were separated. Off responses were generated during wakefulness by auditory cortex stimulation but were not observed under anesthesia. Pronounced off responses, which were middle latency responses exhibiting bis positive waves, were obtained in response to sound stimuli with a frequency of 2 kHz or higher. Vertex stimulation did not induce off responses either during wakefulness or under anesthesia. Off responses are derived from synchronous responses of neurons in the auditory cortex, which are generated when the neurons detect attenuation in the stimulus strength at the end of tone burst stimuli.

Mitigation ofHearing Damage With Liraglutide Treatment inChinchillas After Repeated Blast Exposures at Mild-TBI.

Although hearing protection devices (HPDs) have been widely used during training and combat, over one million veterans experience service-connected hearing loss. Hearing damage has been reported to be associated with blast-induced mild traumatic brain injury (mTBI) and there is a lack of understanding and treatment. Liraglutide is a glucagon-like peptide-1 receptor agonist and a potential treatment for TBI-induced memory deficits. This study aims to investigate the function of the liraglutide to prevent damage and facilitate hearing restoration in chinchillas exposed to multiple high-intensity, mTBI-level blasts. Chinchillas were divided into three treatment groups: blast control, pre-blast drug treatment, and post-blast drug treatment. On day 1, the chinchilla ears were protected by HPDs and exposed to three blasts with peak pressure levels of 15-25 psi. The auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) were recorded pre- and post-blast on day 1 and on days 4, 7, 14, and 28. Substantial acute damage was observed and progressively recovered in chinchillas after the blast exposures. The pre-blast treatment group exhibited the lowest elevation of the ABR threshold and reduction of the wave I amplitude on day 1 after blasts. The liraglutide treatment insignificantly facilitated the recovery of the DPOAE levels and ABR thresholds on days 14 and 28. The pre-blast treatment chinchillas showed reduced MLR amplitudes on days 4 and 7. This study indicated that the pre-blast liraglutide administration provided damage protection against blasts in addition to the HPDs. Current evidence suggests that the effect of liraglutide is more prominent in the early phase of the experiment.

ERP evidence of attentional somatosensory processing and stimulus-response coupling under different hand and arm postures.

We investigated (1) the effects of divided and focused attention on event-related brain potentials (ERPs) elicited by somatosensory stimulation under different response modes, (2) the effects of hand position (closely-placed vs. separated hands) and arm posture (crossed vs. uncrossed forearms) on the attentional modulation of somatosensory ERPs, and (3) changes in the coupling of stimulus- and response-related processes by somatosensory attention using a single-trial analysis of P300 latency and reaction times. Electrocutaneous stimulation was presented randomly to the thumb or middle finger of the left or right hand at random interstimulus intervals (700-900 ms). Subjects attended unilaterally or bilaterally to stimuli in order to detect target stimuli by a motor response or counting. The effects of unilaterally-focused attention were also tested under different hand and arm positions. The amplitude of N140 in the divided attention condition was intermediate between unilaterally attended and unattended stimuli in the unilaterally-focused attention condition in both the mental counting and motor response tasks. Attended infrequent (target) stimuli elicited greater P300 in the unilaterally attention condition than in the divided attention condition. P300 latency was longer in the divided attention condition than in the unilaterally-focused attention condition in the motor response task, but remained unchanged in the counting task. Closely locating the hands had no impact, whereas crossing the forearms decreased the attentional enhancement in N140 amplitude. In contrast, these two manipulations uniformly decreased P300 amplitude and increased P300 latency. The correlation between single-trial P300 latency and RT was decreased by crossed forearms, but not by divided attention or closely-placed hands. Therefore, the present results indicate that focused and divided attention differently affected middle latency and late processing, and that hand position and arm posture also differently affected attentional processes and stimulus-response coupling.

Changes in Auditory Evoked Potentials Increase the Chances of Adults Having Central Auditory Processing Disorder.

Introduction Auditory evoked potentials are widely used in clinical practice to complement the assessment of central auditory processing. However, it is necessary to understand whether these potentials are highly accurate, to assist in the diagnosis of auditory processing disorder. Objective To measure the accuracy of middle and long latency auditory evoked potentials in the diagnosis of auditory processing disorder in adults. Methods This is a case-control study, formed by a control group of 30 individuals with normal auditory processing assessment, and a case group composed of 43 individuals with altered auditory processing assessment. Their sensitivities, specificities, accuracies, positive and negative predictive values for the diagnosis of alterations were measured and compared between the potentials. Results The accuracies of the middle and long latency potentials were 51% and 67%, respectively. The P1-N1-P2 and N2-P300 complexes had an accuracy of 57.5% and 58.9%, respectively. The cognitive potential P300 showed an accuracy of 55%. There was no significant result for the middle-latency potential (OR = 1.8; 95% CI: 0.6-5.4, p > 0.42) and for P300 (OR = 2.63, 95% CI: 0.85-8.43, p > 0.11). However, the result was significant for the long-latency potential (OR = 6.3; 95% CI: 2-19.6, p < 0.01). There was a significant result for the P1-N1-P2 complexes (OR = 6.76, 95% CI:1.4-32.5, p = < 0.010) and N2-P300 (OR = 3.60; 95% CI: 10.16-11.20, p < 0.039). Conclusion Individuals with altered long-latency auditory evoked potential are more likely to have auditory processing disorder and, as such, this test can be used as a complementary tool to confirm the diagnosis.

Skin type and nerve effects on cortical tactile processing: a somatosensory evoked potentials study.

Somatosensory evoked potentials (SEP) studies typically characterize short latency components following median nerve stimulations of the wrist. However, these studies rarely considered 1) skin type (glabrous/hairy) at the stimulation site, 2) nerve being stimulated, and 3) middle latency (>30 ms) components. Our aim was to investigate middle latency SEPs following simple mechanical stimulation of two skin types innervated by two different nerves. 18 adults received 400 mechanical stimulations over four territories of the right hand (two nerves: radial/median; two skin types: hairy/glabrous skin) while their EEG was recorded. Four middle latency components were identified: P50, N80, N130 and P200. As expected, significantly shorter latencies and larger amplitudes were found over the contralateral hemisphere for all components. A skin type effect was found for the N80: glabrous skin stimulations induced larger amplitude than hairy skin stimulations. Regarding nerve effects, median stimulations induced larger P50 and N80. Latency of the N80 was longer after median nerve stimulation compared to radial nerve stimulation. This study showed that skin type and stimulated nerve influence middle latency SEPs, highlighting the importance of considering these parameters in future studies. These modulations could reflect differences in cutaneous receptors and somatotopy. Middle latency SEPs can be used to evaluate the different steps of tactile information cortical processing. Modulation of SEPs components before 100 milliseconds possibly reflects somatotopy and differential processing in SI cortex.

Frequency and Time Domain Analysis of EEG Based Auditory Evoked Potentials to Detect Binaural Hearing in Noise

Hearing loss is a prevalent health issue that affects individuals worldwide. Binaural hearing refers to the ability to integrate information received simultaneously from both ears, allowing individuals to identify, locate, and separate sound sources. Auditory evoked potentials (AEPs) refer to the electrical responses that are generated within any part of the auditory system in response to auditory stimuli presented externally. Electroencephalography (EEG) is a non-invasive technology used for the monitoring of AEPs. This research aims to investigate the use of audiometric EEGs as an objective method to detect specific features of binaural hearing with frequency and time domain analysis techniques. Thirty-five subjects with normal hearing and a mean age of 27.35 participated in the research. The stimuli used in the current study were designed to investigate the impact of binaural phase shifts of the auditory stimuli in the presence of noise. The frequency domain and time domain analyses provided statistically significant and promising novel findings. The study utilized Blackman windowed 18 ms and 48 ms pure tones as stimuli, embedded in noise maskers, of frequencies 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1000 Hz in homophasic (the same phase in both ears) and antiphasic (180-degree phase difference between the two ears) conditions. The study focuses on the effect of phase reversal of auditory stimuli in noise of the middle latency response (MLR) and late latency response (LLR) regions of the AEPs. The frequency domain analysis revealed a significant difference in the frequency bands of 20 to 25 Hz and 25 to 30 Hz when elicited by antiphasic and homophasic stimuli of 500 Hz for MLRs and 500 Hz and 250 Hz for LLRs. The time domain analysis identified the Na peak of the MLR for 500 Hz, the N1 peak of the LLR for 500 Hz stimuli and the P300 peak of the LLR for 250 Hz as significant potential markers in detecting binaural processing in the brain.

Development of Machine-Learning Models for Tinnitus-Related Distress Classification Using Wavelet-Transformed Auditory Evoked Potential Signals and Clinical Data.

Tinnitus is a highly prevalent condition, affecting more than 1 in 7 adults in the EU and causing negative effects on sufferers' quality of life. In this study, we utilised data collected within the "UNITI" project, the largest EU tinnitus-related research programme. Initially, we extracted characteristics from both auditory brainstem response (ABR) and auditory middle latency response (AMLR) signals, which were derived from tinnitus patients. We then combined these features with the patients' clinical data, and integrated them to build machine learning models for the classification of individuals and their ears according to their level of tinnitus-related distress. Several models were developed and tested on different datasets to determine the most relevant features and achieve high performances. Specifically, seven widely used classifiers were utilised on all generated datasets: random forest (RF), linear, radial, and polynomial support vector machines (SVM), naive bayes (NB), neural networks (NN), and linear discriminant analysis (LDA). Results showed that features extracted from the wavelet-scattering transformed AMLR signals were the most informative data. In combination with the 15 LASSO-selected clinical features, the SVM classifier achieved optimal performance with an AUC value, sensitivity, and specificity of 92.53%, 84.84%, and 83.04%, respectively, indicating high discrimination performance between the two groups.

The role of sural nerve reflexes during drop-landing in subjects with and without chronic ankle instability

The purpose of this study was to investigate the functional role of cutaneous reflexes during a single-leg drop-landing task among healthy, neurologically intact adults, and to identify whether individuals with chronic ankle instability (CAI) demonstrate altered reflexes and subsequent ankle kinematics. All subjects were physically active adults and were categorized as control (n = 10, Male = 6, Female = 4) or CAI (n = 9, Male = 4, Female = 5) depending on whether they scored a 0 or ≥ 11 on the Identification of Functional Ankle Instability questionnaire, respectively. Subjects performed 30-40 single-leg drop-landing trials from a platform set to the height of their tibial tuberosity. Muscle activity of four lower leg muscles was collected via surface electromyography, while ankle kinematics were recorded via an electrogoniometer. Non-noxious stimulations were elicited randomly to the ipsilateral sural nerve at two unique phases of the drop-landing task (takeoff and landing). Unstimulated and stimulated trials were used to calculate middle latency reflex amplitudes (80-120ms) and net ankle kinematics (140-220ms) post-stimulation. Mixed-factor ANOVAs were used to identify significant reflexes within groups and differences in reflex amplitudes between groups. Unlike the CAI group, the control group experienced significant facilitation of the Peroneus Longus (PL) and inhibition of the Lateral Gastrocnemius (LG) when stimulated at takeoff, resulting in eversion immediately prior to landing. When stimulated at landing, the control group experienced significantly more inhibition of the PL compared to the CAI group (p = 0.019). These results suggest lower neural excitability for individuals with CAI, which may predispose them to recurrent injury during similar functional tasks.

Study of ultrasound and nerve electromyogram in diagnosis of carpal tunnel syndrome and its severity in the elderly

ABSTRACT Objective: To explore the diagnostic value of ultrasound and nerve electromyography (EMG) in the diagnosis of carpal tunnel syndrome (CTS) and its severity in the elderly. Methods: The data of 140 elderly CTS patients were retrospectively analyzed. The data of 80 patients with other diseases with similar symptoms and high suspicion of CTS during the same period were retrospectively analyzed. Pearson method was used to analyze the correlation between cross-sectional area (CSA) and motor nerve conduction velocity (MCV), distal motor latency (DML), compound muscle action potential (CMAP), sensory conduction velocity (SCV), middle-latency (ML) and sensory nerve action potential (SNAP) levels. The value of CSA, MCV, DML, CMAP, SCV, ML and SNAP in the diagnosis of CTS and its severity was analyzed by receiver operating characteristic (ROC) curve. Results: CSA in mild, moderate and severe groups was positively correlated with DML (P < 0.001) and negatively correlated with CMAP (P < 0.001). The area under the curve (AUC) values of CSA, MCV, DML, CMAP, SCV, ML and SNAP in the diagnosis of normal people and mild CTS were 0.877, 0.787, 0.921, 0.730, 0.860, 0.688 and 0.904. The AUC values of CSA, DML, CMAP, SCV, ML and SNAP in the diagnosis of mild and moderate CTS were 0.863, 0.890, 0.760, 0.848, 0.850 and 0.739, respectively. The AUC values of CSA, MCV, DML and CMAP in the diagnosis of mild and moderate CTS were 0.683, 0.660, 0.870 and 0.693. Conclusion: Ultrasound and nerve EMG are effective in the diagnosis of CTS.

Standardization of Latency and Amplitude Values of Short, Middle and Long Latency Auditory Evoked Potentials in Adults.

Introduction Auditory processing refers to the efficiency and effectiveness with which the central auditory nervous system uses auditory information. Middle- and long-latency auditory evoked potentials are objective electrophysiological tests that can complement the diagnosis of alterations involving central auditory processing. Objective To standardize latency and amplitude values for short-, middle-, and long-latency auditory evoked potentials in adults with normal hearing thresholds. Methods This is a cross-sectional study. Thirty-three adults with normal hearing thresholds, without hearing complaints, and with normal central auditory processing were evaluated. All underwent basic audiological evaluation, central auditory processing assessment, and short-, middle-, and long-latency auditory evoked potentials. Results Absolute latency and interpeak values for middle- and long-latency auditory evoked potentials were lower than internationally suggested. However, for the brainstem auditory evoked potential, the means were within the range considered as normal, as suggested in the equipment. Conclusion The present study provided measurements of normal latencies and amplitudes for short-, middle-, and long-latency auditory evoked potentials in adults.

Diagnosis of Patients Presenting with Vertigo, Headache, and Epileptic Seizure: Evaluating Vestibular Patients by Using Cervical Vestibular Evoked Myogenic Potential and Auditory Middle Latency Responses in the Clinical Setting.

Migraine and vertigo are common complaints seen in clinical practice, and in a few such cases, we also find epileptic manifestations, including migraine-triggered seizures. Currently, patients presenting with vertigo and headache are diagnosed according to established diagnostic criteria for Meniere's disease, vestibular migraine, or vestibular migraine/Meniere's disease overlapping syndrome. In addition to using those diagnostic criteria and the patient's history, cervical vestibular evoked myogenic potential and auditory middle latency responses are useful tools to better understand the physiological background of these patients and also to confirm the diagnosis. Here we report 2 cases: 1 of vestibular migraine/ Meniere's disease overlapping syndrome and 1 of vestibular migraine with epileptic manifestations. Each patient showed potentiation (lack of habituation) in auditory middle latency response, and each showed endolymphatic hydrops in cervical vestibular evoked myogenic potential. The potentiation in auditory middle latency response might be attributable to neuronal hyperexcitability in those patients with migraine or epilepsy, and neurogenic inflammation caused by migraine episodes might affect inner ear function.