Auditory Hypersensitivity Research Articles

Hipersensibilidade auditiva no transtorno do espectro autístico

auditory hypersensitivity in the autistic spectrum disorder has been described in the literature since the very first reports. However, this symptom has not been sufficiently explored, especially regarding possible causes, diagnosis and consequences. to study sensory-perceptual abnormalities in the autistic spectrum disorder, emphasizing auditory hypersensitivity and to discuss their effects in speech therapy based on the literature found until September 2007 in the following database: Scielo, Lilacs, Web of Science, and Medline. sensory-perceptual abnormalities are present in approximately 90% of individuals with autism; no theory has been found to explain this fact. Although the cause of auditory hypersensitivity remains unknown, it is the most common sensory-perceptual abnormality--its prevalence ranges between 15% to 100%. A few rare studies exist on behavioral, electroacoustic and electrophysiological hearing evaluation of autistic children; these studies discuss auditory hypersensitivity. The early diagnosis of this alteration is considered relevant for the possible identification of atypical sensorial markers, especially in hearing and for the better understanding of their impact on the development of communication in autistic individuals.

Enriched acoustic environment rescales auditory sensitivity

Loudness perception may be controlled by a central gain, possibly dependent on the mean level of the acoustic environment. Owing to hearing loss, for instance, a decrease in sensory inputs could increase this central gain and cause an auditory hypersensitivity or hyperacusis. According to this model, individuals with hyperacusis, provided with an enriched acoustic environment specifically designed to compensate for the decrease in sensory inputs, should show an improvement in their hyperacusis. This study showed that such an enriched acoustic environment indeed decreased auditory hypersensitivity: stimuli initially considered as being too loud became comfortable after a few weeks of acoustic stimulation. Therefore, this original approach could provide a solution to the problem of hyperacusis.

Rating of Olfactory Judgements in Migraine Patients

The aim of this study was to evaluate olfactory hypersensitivity (OHS) between attacks in migraine patients. Seventy-four migraine patients and 30 controls were enrolled. The presence of OHS was evaluated using an oral questionnaire and a chemical odour intolerance index. Subjects had to rate the intensity and hedonicity of 12 odourants using a linear rating scale. Twenty-six patients (35.2%) but no control subjects reported an interictal OHS (P<0.001). Logistic regression analysis showed that patients with OHS presented a greater attack frequency, a higher number of odour-induced migraines and visual hypersensitivity when compared with other patients. Disease duration, age, gender and auditory hypersensitivity were not associated with OHS. OHS patients judged odours less pleasant than did other patients and controls, whereas the intensity scores were identical in both groups. OHS between attacks was significantly associated with odour-triggered migraine and an alteration of hedonic judgement.

Association of Auditory Hallucinations and Anticonvulsant Hypersensitivity Syndrome with Carbamazepine Treatment

Carbamazepine is effective in the treatment of acute mania and in the prevention of episodes in bipolar disorder, and it may also be useful in depression, impulse-control disorder and withdrawal from alcohol and benzodiazepine dependence. A potentially life-threatening side effect is the anticonvulsant hypersensitivity syndrome. Here, we describe a patient who developed severe auditory hallucinations followed by a distinct hypersensitivity syndrome most likely induced by carbamazepine treatment.

The discrimination of and orienting to speech and non-speech sounds in children with autism

The present study aimed to find out how different stages of cortical auditory processing (sound encoding, discrimination, and orienting) are affected in children with autism. To this end, auditory event-related potentials (ERP) were studied in 15 children with autism and their controls. Their responses were recorded for pitch, duration, and vowel changes in speech stimuli, and for corresponding changes in the non-speech counterparts of the stimuli, while the children watched silent videos and ignored the stimuli. The responses to sound repetition were diminished in amplitude in the children with autism, reflecting impaired sound encoding. The mismatch negativity (MMN), an ERP indexing sound discrimination, was enhanced in the children with autism as far as pitch changes were concerned. This is consistent with earlier studies reporting auditory hypersensitivity and good pitch-processing abilities, as well as with theories proposing enhanced perception of local stimulus features in individuals with autism. The discrimination of duration changes was impaired in these children, however. Finally, involuntary orienting to sound changes, as reflected by the P3a ERP, was more impaired for speech than non-speech sounds in the children with autism, suggesting deficits particularly in social orienting. This has been proposed to be one of the earliest symptoms to emerge, with pervasive effects on later development.

Auditory hypersensitivity in children and teenagers with autistic spectrum disorder.

To verify if the clinical behavior of auditory hypersensitivity, reported in interviews with parents/caregivers and therapists/teachers of 46 children and teenagers suffering from autistic spectrum disorder, correspond to audiological findings. The clinical diagnosis for auditory hypersensitivity was investigated by means of an interview. Subsequently, a test of the acoustic stapedial reflex was conducted, and responses to intense acoustic stimulus in open field were observed. Of the 46 subjects, 11 (23.9%) were clinically diagnosed as oversensitive to sound and only 2 showed discomfort when exposed to intense acoustic stimulus in open field. There was no statistically significant difference for the test of the ipsilateral acoustic stapedial reflex between the groups. Behavioral manifestations to sounds are not associated to hypersensitivity of the auditory pathways, but instead these are associated to difficulties in the upper processing, involving systems that usually are impaired in autistic spectrum patients, such as the limbic system.

Psychometric Normalization of a Hyperacusis Questionnaire

Clinical hyperacusis consists of a marked intolerance to ordinary environmental sounds, while hearing thresholds are quite often normal. Hyperacusis appears to be a subjective phenomenon, which is not easily defined or quantified by objective measurements. In order to create a tool suitable to quantify and evaluate various hyperacusis symptoms, a questionnaire screening several aspects of auditory symptomatology has been constructed. Two hundred and one subjects (who were either hyperacusic or not), randomly selected from the general population, were tested. A principal component analysis performed on the correlation matrix of the 14 items of the questionnaire isolated three dimensions: attentional, social, and emotional. The three dimensions had satisfactory internal consistency reliability. The mean ± SD total score was 15 ± 6.7 out of 42 (maximum of hyperacusis) and a score greater than 28 seems to represent a strong auditory hypersensitivity. This new psychometric tool should further be tested on hyperacusic patients to verify its relevance in pathology and define the involvement of the three dimensions statistically obtained on the hyperacusis symptomatology.

Fragile X mice develop sensory hyperreactivity to auditory stimuli.

Fragile X syndrome is the most prevalent cause of mental retardation. It is usually caused by the transcriptional inactivation of the FMR-1 gene. Although the cognitive defect is the most recognized symptom of fragile X syndrome, patients also show behavioral problems such as hyperarousal, hyperactivity, autism, aggression, anxiety and increased sensitivity to sensory stimuli. Here we investigated whether fragile X mice (fmr-1 gene knockout mice) exhibit abnormal sensitivity to sensory stimuli. First, hyperreactivity of fragile X mice to auditory stimulus was indicated in the prepulse inhibition paradigm. A moderately intense prepulse tone, that suppresses startle response to a strong auditory stimulus, elicited a significantly stronger effect in fragile X than in control mice. Second, sensory hyperreactivity of fragile X mice was demonstrated by a high seizure susceptibility to auditory stimulation. Selective induction of c-Fos, an early-immediate gene product, indicated that seizures involve auditory brainstem and thalamic nuclei. Audiogenic seizures were not due to a general increase in brain excitability because three different chemical convulsants (kainic acid, bicuculline and pentylenetetrazole) elicited similar effects in fragile X and wild-type mice. These data are consistent with the increased responsiveness of fragile X patients to auditory stimuli. The auditory hypersensitivity suggests an abnormal processing in the auditory system of fragile X mice, which could provide a useful model to study the molecular and cellular changes underlying fragile X syndrome.

Some dynamic and toxic effects of theophylline in horses.

A single intravenous administration of theophylline as aminophylline at 10 mg/kg to four mares induced a diuresis in which maximal urine production was more than seven times the control volume. The diuretic effect was maximal within the first hour post-administration, and lasted approximately 6 h. Theophylline resulted in dose-related tachycardia, polypnoea and nervous symptoms (tactile, visual and auditory hypersensitivity, muscle tremor, sweating) in normal mares, but had only minor effects on arterial and central venous blood pressures, intrapleural pressure, red blood cell variables and plasma proteins. The upper limit of safe plasma theophylline concentration in horses is approximately 15 micrograms/ml. Whenever feasible, the oral or intragastric route of administration should be used as it is safer than the intravenous route.