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Central Auditory Processing: From Diagnosis to Rehabilitation
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Maria Isabel Ramos do Amaral, Leticia Reis Borges, Maria Francisca Colella-Santos
The auditory evoked potential tests have been used as a clinical tool to provide an objective and sensitive index of neurophysiological changes related to training (Alonso and Schochat, 2009). Kraus et al., have reported that changes to CANS neurophysiology secondary to AT can be measured and monitored through long latency evoked auditory potentials (LLEAP, 1995).
Brain stimulation: new directions
Published in Alan Weiss, The Electroconvulsive Therapy Workbook, 2018
The brainstem auditory evoked potential (BAEP) measures the functioning of the auditory nerve and auditory pathways in the brainstem. The test is performed with the patient under sedation or under general anaesthesia. A standard broadband monaural click stimulation is used on the ear tested while a masking noise 30 - 40 dB lower in intensity is used on the contralateral ear. The intensity of the click is 65-70 dB above the click perception threshold and click repeated at a rate of about 10 Hz. BEAPS are used in aiding the assessment of hearing loss (Evans, 2014).
Evoked Measurement of Auditory Sensitivity
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Jeffrey Weihing, Nicholas Leahy
Excitation of auditory neurons by an acoustic stimulus presented at the ear results in electrical activity that can be recorded at the scalp using electrodes. Though small in amplitude, this electrical response can be isolated from the background electroencephalogram (EEG) by averaging the auditory electrical activity across many successive presentations of an acoustic stimulus. This averaged auditory electrical response, or auditory evoked potential (AEP), can be used to infer the relative health of various peripheral and central auditory regions. For instance, a reduction in amplitude of the evoked potential or prolongation of its latency may indicate an inability of the auditory neurons to respond efficiently to the stimulus, or it may reflect a reduced ability of the cochlea to respond to the sound and stimulate the auditory neurons. In either case, the AEP would reflect auditory pathology.
Auditory function and prevalence of specific ear and hearing related pathologies in the general population at age 70
Published in International Journal of Audiology, 2020
Maria Hoff, Tomas Tengstrand, André Sadeghi, Ingmar Skoog, Ulf Rosenhall
In a clinical context, it is of relevance to establish which type of hearing loss a patient has, in order to choose appropriate rehabilitative strategies and predict outcomes. For this purpose, a combination of audiological measures are required. Distortion product otoacoustic emission testing (DPOAE) for instance, is sensitive to early cochlear dysfunction and holds the benefit of being an objective and frequency specific test (Hall et al. 1994; Kemp 2002). DPOAEs decrease as a function of (sensory) hearing loss and emissions are characteristically absent when the pure-tone threshold (PTT) exceeds 50–60 dB HL (Gorga et al. 1997). DPOAEs decrease with ageing, but the evidence is conflicting as to whether these effects are independent of peripheral hearing status or not (Strouse, Ochs, and Hall 1996; Oeken, Lenk, and Bootz 2000; Uchida et al. 2008). Little has been published regarding DPOAEs in the general aged population. In order to evaluate auditory functioning beyond the cochlea, various forms of speech testing and auditory evoked potential responses may be useful. It is well documented that auditory neural responses and speech audiometric performance is degraded in older persons, beyond what can be explained by peripheral hearing loss (Jerger 1992; Frisina and Frisina 1997; Gordon-Salant and Fitzgibbons 2004).
Central deafness: a review of past and current perspectives
Published in International Journal of Audiology, 2019
Frank E. Musiek, Gail D. Chermak, Barbara Cone
Thorough and appropriate audiological testing is critical to accurately diagnose CD and its variants. As was noted in this review several times, the CD literature is limited in quantity and quality, which certainly could have impacted our interpretations and conclusions. We know that patients may not relate all symptoms at the time of the clinical interview, due to the acuteness of their medical condition and/or their psychological state. In addition, the clinician may not ask specific or thorough questions at the time of the interview. Limited published reports on CD report the use of all electrophysiological tools that might have been used to determine the site(s) of lesion. Similarly, behavioural tests to assess auditory perceptions, as well as reveal clinical correlates to the electrophysiological and imaging findings also either were not obtained or not reported. Often, because of a lack of behavioural response to sound, auditory evoked potential testing becomes key. Utilising brainstem, middle latency and late auditory evoked potentials not only helps immensely in reaching an accurate diagnosis, but also in identifying the locus of CANS involvement. Detailed history taking and characterisation of the patient’s symptoms to both verbal and nonverbal sounds are pivotal to accurately diagnosing CD and its variants. Patients with CD experience recovery, to varying degrees, with simple and basic auditory functions recovering first.
Spatial hearing processing: electrophysiological documentation at subcortical and cortical levels
Published in International Journal of Neuroscience, 2019
Nematollah Rouhbakhsh, John Mahdi, Jacob Hwo, Baran Nobel, Fati Mousave
Auditory brainstem response (ABR), frequency-following response (FFR) and cortical auditory evoked potential (CAEP) as electrophysiological tools are utilized in the present investigation. The ABR is an early brainstem electrical response evoked by a brief stimulus and happens inside 10–15 ms after stimulus initiation and incorporates seven waves, wave I–VII [21]. The FFR is an ongoing response to low-frequency stimuli by neural activity. It is phase-locked to every cycle of a stimulus waveform or its envelope periodicity [22]. The CAEP is a late response that happens inside 50–200 ms after stimulus initiation and is evoked for stimulus onset, offset and changes [23]. In adults, it has several components known as P1, N1, P2 and N2 [24].