China
Africa
Explore chapters and articles related to this topic
Canine Audiology
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Kristine E. Sonstrom, Peter M. Scheifele
Sound levels are expressed in decibels (dB) relative to a reference. The decibel represents a logarithm of a ratio of two sound pressures or two corresponding sound intensities (Humes et al., 2006). It is a unit of sound intensity relative to a reference. In air, the reference quantity in the denominator of the ratio is either a sound pressure of 20 µPa or a sound intensity of 10−12 watts/m2. Identifying the reference to a decibel level is important; without identifying the reference there is a lack of context and the true sound pressure level can be misinterpreted by the reader. When performing ABR testing in dogs, it is appropriate to use a decibel reference relative to the actual intensity sound pressure level (e.g., pe SPL) rather than a reference relative to “normal” human hearing (e.g., n HL). Intensity levels in humans are referenced as dB HL, or decibels hearing level, when utilizing a behavioral audiometer. The dB HL scale references accepted standards for normal human hearing, where zero dB is the average normal hearing for each audiometric test frequency in the human (Mendel et al., 1999). In other words, audiometric zero (0 dB HL) refers to the average hearing level at each frequency for a normal hearing human population. Zero dB HL is not equivalent to zero dB SPL (e.g., at 250 Hz, zero dB HL = 24.5 dB SPL (Audiometric zero, McGraw-Hill Concise Dictionary of Modern Medicine, 2002).
Central Auditory Processing Disorders
Published in James Law, Alison Parkinson, Rashmin Tamhne, David Hall, Communication Difficulties in Childhood, 2017
The first objective in the assessment of possible CAPD is to rule out a hearing loss caused by peripheral auditory dysfunction (see alsoChapters 4 and 17). The peripheral auditory system is defined as the outer ear, the tympanic membrane and the middle ear, the inner ear (cochlea) and the eighth cranial (auditory) nerve. Audiology terms and procedures important in a discussion of CAPD assessment are defined in the Glossary. Pure tone audiometry is a measure of hearing sensitivity for pure tone stimuli (sinusoids) ranging in octave frequencies from 250 Hz up to 8000 Hz and, in CAPD assessment, also including 3000 Hz and 6000 Hz. Hearing test results, recorded as the threshold in decibels hearing level (dB HL) for these frequencies, are graphed on an audiogram. A young, perfectly normal person has hearing threshold levels of 0 dB HL across this frequency region. The clinically normal region on the audiogram, however, is from 0 to 20 dB HL.
The Role of the Audiologist in Life Care Planning
Published in Roger O. Weed, Debra E. Berens, Life Care Planning and Case Management Handbook, 2018
William D. Mustain, Carolyn Wiles Higdon
The audiogram is a graphic representation of hearing sensitivity. It shows an individual's threshold for tones of different frequencies. Frequency, measured in hertz (Hz), is plotted along the abscissa and intensity, measured in decibels (dB), is plotted along the ordinate. Thresholds for the left ear are plotted with an X and thresholds for the right ear are plotted with a 0. Normal hearing is considered to be between –10 and +20 dB HL. Hearing level (HL) is the number of decibels relative to normal hearing, which is 0 dB HL on the audiogram. The audiogram shown in Figure 10.2 indicates normal hearing in the left ear and a hearing loss in the right ear. The area enclosed by the two wavy lines is called the speech banana. This area represents the frequencies and intensities of spoken English and assists the audiologist in explaining how a given hearing loss may affect a person's ability to understand speech. In the example audiogram, the person will not be able to hear speech sounds above 1,000 Hz in the right ear because his/her thresholds are out of the speech banana. Were this person to have this degree of hearing loss in both ears, he may be expected to have difficulty understanding high-frequency speech sounds such as s, f, th, p, t, k, sh, and ch, for example. In addition, he may be expected to have considerable difficulty understanding conversational speech in the presence of background noise, such as in a cafeteria. Figure 10.3 shows the frequency of various speech sounds, as well as the intensity of some common environmental sounds.
Neutrophil-lymphocyte ratio as a valuable prognostic marker in idiopathic sudden sensorineural hearing loss
Published in Acta Oto-Laryngologica, 2020
Jeong Wook Kang, Myung Gu Kim, Sung Su Kim, Heh-In Im, Sung Hwa Dong, Sang Hoon Kim, Seung Geun Yeo
The admitted patients underwent daily pure tone audiometry (PTA) to evaluate their responses to treatment while hospitalized. This study, however, analyzed PTA results before treatment and 6 months after the end of treatment. PTA was measured at frequencies of 125, 250, 500, 1000, 2000, 3000, 4000, and 8000 Hz, with the hearing gain at each frequency calculated as the difference between PTAs before and 6 months after treatment. PTA average was calculated as the arithmetic mean of the thresholds at 500, 1000, 2000, and 4000 Hz [6]. The audiogram shapes were classified according to Pan’s classification, except that the gradual and steep slopes were combined [7]. The severity of hearing loss was defined as normal (≤25 decibel hearing level [dB HL]), mild (26–39 dB HL), moderate (40–54 dB HL), moderate to severe (55–69 dB HL), severe (70–89 dB HL), and profound (>90 dB HL), according to the 1964 ISO classification.
Peripheral and central auditory function in adults with epilepsy and treated with carbamazepine
Published in Hearing, Balance and Communication, 2019
Sherifa A. Hamed, Amira M. Oseily
All participants underwent basic audiological evaluation that included: initial otoscopic examination, standard pure tone air and bone conduction audiometry (PTA). Pure tone audiometric thresholds were measured at 0.25–8 kHz (0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 kHz) and pure average thresholds for the right and left ears were obtained (Interacoustics model AC40, v.1.28, Assens Denmark). Hearing thresholds had been determined in decibel hearing level (dB HL). The examined ears had been defined as normal if no absolute threshold level >20 dB had been measured over the whole frequency range. Threshold shifts in PTA were considered significant if they had at least 10 dB changes in more than two consecutive frequencies, or if a threshold greater than 20 dB had been observed in any audiometric range. Hearing loss had been calculated for each ear separately as the amount of threshold shifts above the standard audiometric zero. Grading of hearing impairment had been adopted into mild, moderate, moderately severe and severe according to Northern and Downs [37] (defined as average threshold between 25–40 dB, 41–55 dB, 56–70 dB and 71–90 dB, respectively). Immittance testing (Amplaid Model 720 immittance bridge, Amplaid, Milan, Italy), low frequency tympanometry (+200 top –400 dapa) and acoustic (stapedius) reflex (Middle Ear Analyzer Interacoustics, Az26, Assens, Denmark) were used to assess middle ear function.
Prevalence of severe-to-Profound hearing loss in the adult Swedish population and comparison with cochlear implantation rate
Published in Acta Oto-Laryngologica, 2022
Christian Löfvenberg, Per-Inge Carlsson, Marie Louise Barrenäs, Åsa Skagerstrand, David Simic, Jonas Carlsson, Jessica Wigdén, Eva Westman
We defined STPHL as a bilateral pure tone average at frequencies of 0.5, 1, 2, and 4 kHz (PTA4) of 70 dB hearing level or worse [3]. The hearing level was determined by a qualified audiologist in public hearing service based on international audiology methods (ISO 8253–1, 1989) through pure tone audiometry performed in a soundproof booth using a clinical audiometer. Hearing thresholds were measured at octave frequencies of 0.125–8, 3, and 6 kHz. If masking was performed, we only used the masked value for analysis. The air conduction hearing thresholds were present an analysed in all last performed audiograms. Numerous patients showed missing bone conduction hearing thresholds and speech audiometry; accordingly, they were not analysed.