Auditory evoked potentials: predicting speech therapy outcomes in children with phonological disorders

OBJECTIVES:

This study investigated whether neurophysiologic responses (auditory evoked potentials) differ between typically developed children and children with phonological disorders and whether these responses are modified in children with phonological disorders after speech therapy.

METHODS:

The participants included 24 typically developing children (Control Group, mean age: eight years and ten months) and 23 children clinically diagnosed with phonological disorders (Study Group, mean age: eight years and eleven months). Additionally, 12 study group children were enrolled in speech therapy (Study Group 1), and 11 were not enrolled in speech therapy (Study Group 2). The subjects were submitted to the following procedures: conventional audiological, auditory brainstem response, auditory middle-latency response, and P300 assessments. All participants presented with normal hearing thresholds. The study group 1 subjects were reassessed after 12 speech therapy sessions, and the study group 2 subjects were reassessed 3 months after the initial assessment. Electrophysiological results were compared between the groups.

RESULTS:

Latency differences were observed between the groups (the control and study groups) regarding the auditory brainstem response and the P300 tests. Additionally, the P300 responses improved in the study group 1 children after speech therapy.

CONCLUSION:

The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy.     

Sensitivity and specificity of auditory steady-state response testing

INTRODUCTION:

The ASSR test is an electrophysiological test that evaluates, among other aspects, neural synchrony, based on the frequency or amplitude modulation of tones.

OBJECTIVE:

The aim of this study was to determine the sensitivity and specificity of auditory steady‐state response testing in detecting lesions and dysfunctions of the central auditory nervous system.

METHODS:

Seventy volunteers were divided into three groups: those with normal hearing; those with mesial temporal sclerosis; and those with central auditory processing disorder. All subjects underwent auditory steady‐state response testing of both ears at 500 Hz and 2000 Hz (frequency modulation, 46 Hz). The difference between auditory steady‐state response‐estimated thresholds and behavioral thresholds (audiometric evaluation) was calculated.

RESULTS:

Estimated thresholds were significantly higher in the mesial temporal sclerosis group than in the normal and central auditory processing disorder groups. In addition, the difference between auditory steady‐state response‐estimated and behavioral thresholds was greatest in the mesial temporal sclerosis group when compared to the normal group than in the central auditory processing disorder group compared to the normal group.

DISCUSSION:

Research focusing on central auditory nervous system (CANS) lesions has shown that individuals with CANS lesions present a greater difference between ASSR‐estimated thresholds and actual behavioral thresholds; ASSR‐estimated thresholds being significantly worse than behavioral thresholds in subjects with CANS insults. This is most likely because the disorder prevents the transmission of the sound stimulus from being in phase with the received stimulus, resulting in asynchronous transmitter release. Another possible cause of the greater difference between the ASSR‐estimated thresholds and the behavioral thresholds is impaired temporal resolution.

CONCLUSIONS:

The overall sensitivity of auditory steady‐state response testing was lower than its overall specificity. Although the overall specificity was high, it was lower in the central auditory processing disorder group than in the mesial temporal sclerosis group. Overall sensitivity was also lower in the central auditory processing disorder group than in the mesial temporal sclerosis group.     

Formal auditory training in adult hearing aid users

INTRODUCTION

Individuals with sensorineural hearing loss are often able to regain some lost auditory function with the help of hearing aids. However, hearing aids are not able to overcome auditory distortions such as impaired frequency resolution and speech understanding in noisy environments. The coexistence of peripheral hearing loss and a central auditory deficit may contribute to patient dissatisfaction with amplification, even when audiological tests indicate nearly normal hearing thresholds.

OBJECTIVE

This study was designed to validate the effects of a formal auditory training program in adult hearing aid users with mild to moderate sensorineural hearing loss.

METHODS

Fourteen bilateral hearing aid users were divided into two groups: seven who received auditory training and seven who did not. The training program was designed to improve auditory closure, figure-to-ground for verbal and nonverbal sounds and temporal processing (frequency and duration of sounds). Pre- and post-training evaluations included measuring electrophysiological and behavioral auditory processing and administration of the Abbreviated Profile of Hearing Aid Benefit (APHAB) self-report scale.

RESULTS

The post-training evaluation of the experimental group demonstrated a statistically significant reduction in P3 latency, improved performance in some of the behavioral auditory processing tests and higher hearing aid benefit in noisy situations (p-value < 0,05). No changes were noted for the control group (p-value <0,05).

CONCLUSION

The results demonstrated that auditory training in adult hearing aid users can lead to a reduction in P3 latency, improvements in sound localization, memory for nonverbal sounds in sequence, auditory closure, figure-to-ground for verbal sounds and greater benefits in reverberant and noisy environments.     

Temporal resolution in individuals with neurological disorders

OBJECTIVE:

Temporal processing refers to the ability of the central auditory nervous system to encode and detect subtle changes in acoustic signals. This study aims to investigate the temporal resolution ability of individuals with mesial temporal sclerosis and to determine the sensitivity and specificity of the gaps-in-noise test in identifying this type of lesion.

METHOD:

This prospective study investigated differences in temporal resolution between 30 individuals with normal hearing and without neurological lesions (G1) and 16 individuals with both normal hearing and mesial temporal sclerosis (G2). Test performances were compared, and the sensitivity and specificity were calculated.

RESULTS:

There was no difference in gap detection thresholds between the two groups, although G1 revealed better average thresholds than G2 did. The sensitivity and specificity of the gaps-in-noise test for neurological lesions were 68% and 98%, respectively.

CONCLUSIONS:

Temporal resolution ability is compromised in individuals with neurological lesions caused by mesial temporal sclerosis. The gaps-in-noise test was shown to be a sensitive and specific measure of central auditory dysfunction in these patients.     

Audiological manifestations in HIV-positive adults

OBJECTIVE:

To characterize the findings of behavioral hearing assessment in HIV-positive individuals who received and did not receive antiretroviral treatment.

METHODS:

This research was a cross-sectional study. The participants were 45 HIV-positive individuals (18 not exposed and 27 exposed to antiretroviral treatment) and 30 control-group individuals. All subjects completed an audiological evaluation through pure-tone audiometry, speech audiometry, and high-frequency audiometry.

RESULTS:

The hearing thresholds obtained by pure-tone audiometry were different between groups. The group that had received antiretroviral treatment had higher thresholds for the frequencies ranging from 250 to 3000 Hz compared with the control group and the group not exposed to treatment. In the range of frequencies from 4000 through 8000 Hz, the HIV-positive groups presented with higher thresholds than did the control group. The hearing thresholds determined by high-frequency audiometry were different between groups, with higher thresholds in the HIV-positive groups.

CONCLUSION:

HIV-positive individuals presented poorer results in pure-tone and high-frequency audiometry, suggesting impairment of the peripheral auditory pathway. Individuals who received antiretroviral treatment presented poorer results on both tests compared with individuals not exposed to antiretroviral treatment.     

Speech and non-speech processing in children with phonological disorders: an electrophysiological study

OBJECTIVE:

To determine whether neurophysiological auditory brainstem responses to clicks and repeated speech stimuli differ between typically developing children and children with phonological disorders.

INTRODUCTION:

Phonological disorders are language impairments resulting from inadequate use of adult phonological language rules and are among the most common speech and language disorders in children (prevalence: 8 ‐ 9%). Our hypothesis is that children with phonological disorders have basic differences in the way that their brains encode acoustic signals at brainstem level when compared to normal counterparts.

METHODS:

We recorded click and speech evoked auditory brainstem responses in 18 typically developing children (control group) and in 18 children who were clinically diagnosed with phonological disorders (research group). The age range of the children was from 7‐11 years.

RESULTS:

The research group exhibited significantly longer latency responses to click stimuli (waves I, III and V) and speech stimuli (waves V and A) when compared to the control group.

DISCUSSION:

These results suggest that the abnormal encoding of speech sounds may be a biological marker of phonological disorders. However, these results cannot define the biological origins of phonological problems. We also observed that speech‐evoked auditory brainstem responses had a higher specificity/sensitivity for identifying phonological disorders than click‐evoked auditory brainstem responses.

CONCLUSIONS:

Early stages of the auditory pathway processing of an acoustic stimulus are not similar in typically developing children and those with phonological disorders. These findings suggest that there are brainstem auditory pathway abnormalities in children with phonological disorders.     

Change in Tinnitus after Treatment of Vestibular Schwannoma: Microsurgery vs. Gamma Knife Radiosurgery

Purpose

Tinnitus is a very common symptom of vestibular schwannoma, present in 45 to 80% of patients. We evaluated changes in tinnitus after translabyrinthine microsurgery (TLM) or gamma knife radiosurgery (GKS).

Materials and Methods

Among 78 patients with vestibular schwannoma who underwent TLM or GKS at Severance Hospital from 2009-2012, 46 patients with pre- or postoperative tinnitus who agreed to participate were enrolled. Pure tone audiometry, tinnitus handicap inventory (THI), visual analogue scale (VAS) scores for loudness, awareness, and annoyance were measured before and after treatment. Changes of THI and VAS were analysed and compared according to treatment modality, tumour volume, and preoperative residual hearing.

Results

In the TLM group (n=27), vestibulocochlear nerves were definitely cut. There was a higher rate of tinnitus improvement in TLM group (52%) than GKS group (16%, p=0.016). The GKS group had a significantly higher rate of tinnitus worsening (74%) than TLM group (11%, p<0.001). Mean scores of THI and VAS scores significantly decreased in the TLM group in contrast to significant increases in the GKS group. Tumor volume and preoperative hearing did not affect the changes in THI or VAS.

Conclusion

GKS can save vestibulocochlear nerve continuity but may damage the cochlea, cochlear nerve and can cause worsening tinnitus. In cases where hearing preservation is not intended, microsurgery with vestibulocochlear neurectomy during tumor removal can sometimes relieve or prevent tinnitus.     

Non-flat audiograms in sensorineural hearing loss and speech perception

OBJECTIVE:

The audibility thresholds for the sound frequency of 137 upward- and downward-sloping audiograms showing sensorineural hearing loss were selected and analyzed in conjunction with speech recognition thresholds obtained from individuals seen at a public otolaryngology clinic to determine which frequencies in slope audiograms best represent speech recognition thresholds.

METHOD:

The linear regression model and mean square error were used to determine the associations between the threshold values.

RESULT:

The mean square error identified larger errors when using thresholds of 500, 1000, and 2000 Hz than when using audibility thresholds of 500, 1000, 2000, and 4000 Hz. The linear regression model showed a higher correlation (91%) between the audiogram thresholds for frequencies of 500, 1000, 2000, and 4000 Hz than for the frequencies of 500, 1000, and 2000 Hz (88%).

CONCLUSION:

Frequencies of 500, 1000, 2000, and 4000 Hz were the most significant in predicting the speech recognition threshold.     

Tinnitus,Traumatic Brain Injury,and Posttraumatic Stress Disorder in the Military

Purpose

Acoustic trauma is more prevalent in military settings, especially among individuals with combat-related military occupational specialties. Gunfire, improvised explosive devices, and mortar explosions are a few examples that may cause hearing degradation and tinnitus. It is possible that the same events that are associated with auditory problems can cause traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD).

Method

This paper reviews the distinct and overlapping symptoms of tinnitus, TBI, and PTSD, and how these disorders interact to synergistically promote negative outcomes.

Results

Tinnitus may serve as a significant contributor to symptoms of TBI and PTSD. Therefore, tinnitus subtypes could be identified as physiologically or psychologically based, or both.

Conclusions

Additional research is warranted to determine the common and unique symptoms and associated neurological pathways of tinnitus, TBI, and PTSD. Brief treatment recommendations are provided, including a multidisciplinary approach for the physical and psychological distress associated with tinnitus.

     

(Central) Auditory Processing: the impact of otitis media

OBJECTIVE:

To analyze auditory processing test results in children suffering from otitis media in their first five years of age, considering their age. Furthermore, to classify central auditory processing test findings regarding the hearing skills evaluated.

METHODS:

A total of 109 students between 8 and 12 years old were divided into three groups. The control group consisted of 40 students from public school without a history of otitis media. Experimental group I consisted of 39 students from public schools and experimental group II consisted of 30 students from private schools; students in both groups suffered from secretory otitis media in their first five years of age and underwent surgery for placement of bilateral ventilation tubes. The individuals underwent complete audiological evaluation and assessment by Auditory Processing tests.

RESULTS:

The left ear showed significantly worse performance when compared to the right ear in the dichotic digits test and pitch pattern sequence test. The students from the experimental groups showed worse performance when compared to the control group in the dichotic digits test and gaps-in-noise. Children from experimental group I had significantly lower results on the dichotic digits and gaps-in-noise tests compared with experimental group II. The hearing skills that were altered were temporal resolution and figure-ground perception.

CONCLUSION:

Children who suffered from secretory otitis media in their first five years and who underwent surgery for placement of bilateral ventilation tubes showed worse performance in auditory abilities, and children from public schools had worse results on auditory processing tests compared with students from private schools.     

Neurophysiology of hearing in patients with mucopolysaccharidosis type IV

Background

Hearing impairment is a common problem in patients with mucopolysaccharidosis IV (MPS IV) throughout their life. Many of the adult patients with MPS IV exhibit permanent or severe hearing loss. However, there has been no systematic review of detailed audiological test results in MPS IV.

OTOF mutations revealed by genetic analysis of hearing loss families including a potential temperature sensitive auditory neuropathy allele

Introduction

The majority of hearing loss in children can be accounted for by genetic causes. Non‐syndromic hearing loss accounts for 80% of genetic hearing loss in children, with mutations in DFNB1/GJB2 being by far the most common cause. Among the second tier genetic causes of hearing loss in children are mutations in the DFNB9/OTOF gene.

Methods

In total, 65 recessive non‐syndromic hearing loss families were screened by genotyping for association with the DFNB9/OTOF gene. Families with genotypes consistent with linkage or uninformative for linkage to this gene region were further screened for mutations in the 48 known coding exons of otoferlin.

Results

Eight OTOF pathological variants were discovered in six families. Of these, Q829X was found in two families. We also noted 23 other coding variant, believed to have no pathology. A previously published missense allele I515T was found in the heterozygous state in an individual who was observed to be temperature sensitive for the auditory neuropathy phenotype.

Conclusions

Mutations in OTOF cause both profound hearing loss and a type of hearing loss where otoacoustic emissions are spared called auditory neuropathy.     

AUNX1, a novel locus responsible for X linked recessive auditory and peripheral neuropathy, maps to Xq23-27.3

Background

We report here the genetic characterisation of a large five generation Chinese family with the phenotypic features of auditory neuropathy and progressive peripheral sensory neuropathy, and the genetic feature of X linked recessive inheritance. Disease onset was at adolescence (at an average age of 13 years for six affected subjects). The degree of hearing impairment varied from mild to severe, with decreased otoacoustic emissions; auditory brainstem responses were lacking from onset.

Methods

Two‐point and multipoint model based linkage analysis using the MILNK and LINKMAP programs of the FASTLINK software package produced maximum two‐point and multipoint LOD scores of 2.41 and 2.41, respectively.

Results

These findings define a novel X linked auditory neuropathy locus/region (AUNX1, Xq23–q27.3). This region is 42.09 cM long and contains a 28.07 Mb region with flanking markers DXS1220 and DXS8084, according to the Rutgers Combined Linkage‐Physical Map, build 35. However, mutation screen of the candidate gene SLC6A14 within the region did not identify the causative genetic determinant for this large Chinese family.     

Flufenamic acid prevents behavioral manifestations of salicylate-induced tinnitus in the rat

Introduction

Tinnitus is defined as a phantom auditory sensation, the perception of sound in the absence of external acoustic stimulation. Given that flufenamic acid (FFA) blocks TRPM2 cation channels, resulting in reduced neuronal excitability, we aimed to investigate whether FFA suppresses the behavioral manifestation of sodium salicylate (SSA)-induced tinnitus in rats.

Material and methods

Tinnitus was evaluated using a conditioned lick suppression model of behavioral testing. Thirty-one Wistar rats, randomly divided into four treatment groups, were trained and tested in the behavioral experiment: (1) control group: DMSO + saline (n = 6), (2) SSA group: DMSO + SSA (n = 6), (3) FFA group: FFA (66 mg/kg bw) + saline (n = 9), (4) FFA + SSA group: FFA (66 mg/kg bw) + SSA (400 mg/kg bw) (n = 10). Localization of TRPM2 to the plasma membrane of cochlear nucleus neurons was demonstrated by confocal microscopy.

Results

Pavlovian training resulted in strong suppression of licking, having a mean value of 0.05 ±0.03 on extinction day 1, which is below the suppression training criterion level of 0.20 in control tinnitus animals. The suppression rate for rats having both FFA (66 mg/kg bw) and SSA (400 mg/kg bw) injections was significantly lower than that for the rats having SSA injections (p < 0.01).

Conclusions

We suggest that SSA-induced tinnitus could possibly be prevented by administration of a TRPM2 ion channel antagonist, FFA at 66 mg/kg bw.     

Inner ear involvement in Fabry disease: Clinical and audiometric evaluation of a large cohort of patients followed in a reference centre

Background

Fabry disease (FD) is a lysosomal storage disorder (LSD) that involves the cochleovestibular system. Tinnitus and progressive sensorineural hearing loss are frequent complains. A stabilization of hearing function has been reported with enzyme replacement therapy (ERT). This study aims to characterize the inner ear involvement, identify factors associated to hearing loss and evaluate the effect of ERT on the hearing function of FD patients.

Sound localization and occupational noise

OBJECTIVE:

The aim of this study was to determine the effects of occupational noise on sound localization in different spatial planes and frequencies among normal hearing firefighters.

METHOD:

A total of 29 adults with pure-tone hearing thresholds below 25 dB took part in the study. The participants were divided into a group of 19 firefighters exposed to occupational noise and a control group of 10 adults who were not exposed to such noise. All subjects were assigned a sound localization task involving 117 stimuli from 13 sound sources that were spatially distributed in horizontal, vertical, midsagittal and transverse planes. The three stimuli, which were square waves with fundamental frequencies of 500, 2,000 and 4,000 Hz, were presented at a sound level of 70 dB and were randomly repeated three times from each sound source. The angle between the speaker''s axis in the same plane was 45°, and the distance to the subject was 1 m.

RESULT:

The results demonstrate that the sound localization ability of the firefighters was significantly lower (p<0.01) than that of the control group.

CONCLUSION:

Exposure to occupational noise, even when not resulting in hearing loss, may lead to a diminished ability to locate a sound source.     

Pain Sensitivity in Sleepy Pain-Free Normals

Study Objective:

Past studies have shown that acute experimental reduction of time in bed in otherwise healthy, non-sleepy people leads to hyperalgesia. We hypothesized that otherwise healthy, sleepy people may also exhibit hyperalgesia relative to their non-sleepy counterparts.

Design:

Between-groups sleep laboratory study.

Setting:

Hospital-based sleep disorders center.

Participants:

Twenty-seven, healthy, normal participants (age 18–35 years) were recruited and categorized into sleepy and non-sleepy groups based on their average sleep latencies on a screening multiple sleep latency test (MSLT).

Interventions:

Both groups were then allowed 8 hours time in bed, following which they underwent pain sensitivity testing (10:30 and 14:30) and sleepiness assessments by the MSLT (10:00, 12:00, 14:00, and 16:00). Pain sensitivity assessments were made by measuring finger withdrawal latencies to a radiant heat source delivering 5 different heat intensities.

Measurements and Results:

This study showed that after only one night of 8 hours time in bed, the sleepy participants continued to be sleepy and exhibited a more rapid finger withdrawal response (i.e., increased pain sensitivity) to radiant heat than non-sleepy participants.

Conclusion:

This suggests that sleepy individuals experience hyperalgesia in response to a painful stimulus when compared with non-sleepy individuals.

Citation:

Chhangani BS; Roehrs TA; Harris EJ; Hyde M; Drake C; Hudgel DW; Roth T. Pain sensitivity in sleepy pain-free normals. SLEEP 2009;32(8):1011-1017.     

Previous mild traumatic brain injury and postural-control dynamics

Context:

Postural control and cognitive function are adversely affected by acute mild traumatic brain injury (mTBI). Whether postural-control deficits persist beyond the acute stage in individuals with a history of mTBI is unclear.

Objective:

To determine if postural-control deficits persist in individuals with a history of mTBI.

Design:

Retrospective cross-sectional study.

Setting:

University research laboratory.

Patients or Other Participants:

As part of an ongoing investigation examining cognitive and motor deficits associated with mTBI, 224 individuals participated in the study. Of these, 62 participants self-reported at least 1 previous physician-diagnosed mTBI.

Intervention(s):

Postural control was assessed using the NeuroCom Sensory Organization Test (SOT) postural-assessment battery.

Main Outcome Measure(s):

The SOT postural assessment yields 4 indices of postural control: a composite balance score, a visual ratio score, a somatosensory score, and a vestibular score. Postural dynamics were also examined by calculating approximate entropy of center-of-pressure excursions in the anteroposterior and mediolateral axis for each test condition.

Results:

Minimal differences in the SOT indices were noted among individuals with and without a history of previous mTBI (P > .05). In the group with a history of mTBI, anteroposterior postural irregularity decreased as postural difficulty increased. In contrast, the group without a history of mTBI displayed increased postural irregularity in the mediolateral direction.

Conclusions:

Individuals with a history of mTBI exhibited altered postural dynamics compared with individuals without a history of mTBI. These findings support the notion that changes in cerebral functioning that affect postural control may persist long after acute injury resolution.     

The audiological profile of adults with and without hypertension

OBJECTIVE:

To determine whether there is any influence of systemic arterial hypertension on the peripheral auditory system.

METHODS:

This was a cross-sectional study that investigated 40 individuals between 30 and 50 years old, who were divided into groups with and without systemic arterial hypertension, using data from high-frequency audiometry, transient-evoked otoacoustic emissions and distortion-product otoacoustic emissions. The results were compared with those from groups of normal-hearing individuals, with and without systemic arterial hypertension, who underwent the pure-tone audiometry test. All individuals also underwent the following procedures: otoscopy, acoustic immittance measures, pure-tone audiometry at frequencies from 250 to 16000 Hz, transient-evoked otoacoustic emissions test and distortion-product otoacoustic emissions test.

RESULTS:

No statistically significant difference was observed between the groups with and without systemic arterial hypertension in either conventional or high-frequency audiometry. Regarding transient-evoked otoacoustic emissions, there was a trend toward statistical significance whereby the systemic arterial hypertension group showed lower results. Regarding distortion-product otoacoustic emissions, the systemic arterial hypertension group showed significantly lower results at the following frequencies: 1501, 2002, and 3003 Hz. A discriminant analysis indicated that the distortion-product otoacoustic emissions variables best distinguished individuals with and without systemic arterial hypertension.

CONCLUSION:

Data from this study suggest cochlear dysfunction in individuals with systemic arterial hypertension because their otoacoustic emission results were lower than those in the systemic arterial hypertension group.