Week 3, Fall 2007

This week I saw an extremely interesting client. The client was in his 20s with a history of occupational noise exposure. He had difficulty hearing me initially during the case history interview and while the headphone was in place prior to immittance testing. He had been evaluated a month prior to his visit to our clinic, and he hoped to get hearing aids at this visit. He had normal tympanograms and normal ARTs. Pure tone testing was more outstanding.

The client was evaluated with insert earphones and responded by clicking the control button. Pure tone air conduction testing revealed a significant difference from his last evaluation, particularly in his right ear. In particular, his right AC pure tone threshold at 2000 Hz appeared to have worsened 25 dB HL over the course of one month. His hearing loss in his right ear moved from a mild SN HL to a moderate SN HL. The configuration and degree of hearing loss changed in his left ear from a moderate to a moderately-severe SN HL from his last evaluation to a moderate to severe SN HL at the present evaluation.

When pure tone bone conduction testing was performed, thresholds appeared to be between 15 and 20 dB worse than the best air conduction scores. I was not confident in these results, so my supervisor confirmed air conduction thresholds (within 5 dB) in a different test booth, under supraaural headphones, with a hand raising response task. SRTs were in good agreement with PTAs, and at this point, I was completely confused. I completed a 2-6 kHz OAE screen with a 4/6 pass criteria. The patient passed bilaterally. Because of the dramatic change in his thresholds and because of inconclusive test results, my supervisor advised me to refer him to an ENT.

Following the client's departure, my supervisor and I discussed the possibility of a functional hearing loss. It was difficult for me to conceive of a functional loss because the client responded so consistently during behavioral testing. The following article, however, describes a study in which participants were employed to simulate a functional hearing loss. Different strategies were used in order to make the hearing losses more realistic. Detailed descriptions of counting methods (count presentations to judge the intensity level), loudness judgment (responding to an internal loudness judgment), counting with a loudness reference, no response, and random response were given. Although malingerers in the study were discovered with cross-checks, some participants were quite good at faking. The authors recommend using non-traditional testing methods, such as CON-SOT-LOT (continuous, standard-off-time, lengthened-off-time) (Martin et al, 2000), to test those suspected of functional hearing losses.

http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=5154041&site=ehost-live

Check out the supplemental activities & the survey questions ... they're great resources for anyone else who may be interested in pediatric audiology. :-)

Also, you all may recognize a couple of the authors cited in the article.

Week 2, Fall 2007

This week I saw a college-aged female client who reported that she was having difficulties hearing. She was a student in a dentistry program, and she described having extreme difficulty understanding her professors during clinical practicum. She explained that the background noise and muffled speech (due to wearing surgical masks) was making it nearly impossible to listen to lectures. She was receiving no visual cues because she was unable to see her professors' mouths behind the surgical masks. She also reported having difficulty at home and in social situations. She noted that she was born with a hearing loss, but she was unsure of the details regarding that diagnosis. From the client's case history, I anticipated that she would have a mild to moderate sensorineural hearing loss.

Immittance testing revealed normal tympanograms and normal ipsilateral and contralateral ARTs at all test frequencies. Air conduction and bone conduction testing revealed normal hearing from 250 to 4000 Hz with a slight bilateral S-N hearing loss at 500 Hz. Diagnostic OAEs were performed, and robust responses were noted at all test frequencies. Speech testing was not performed due to time constraints in the client's schedule.

Test results did not agree with my initial impression of the client. She had difficulty understanding my speech when I was not looking directly at her or when others were speaking in the clinic, and her case history suggested that she had a more severe HL. Further speech testing and CAPD testing were scheduled to evaluate other issues that may be the source of her difficulty. Attention issues or central auditory processing issues may be affecting her speech perception and still need to be assessed in order to rule out a functional loss.

Separating attention deficits and auditory processing disorders has been a controversial issue lately in audiology. The following article describes a multimodal testing approach. According to the authors, a CAPD diagnosis cannot be made from a hearing evaluation alone. They contend that evaluating receptive language, cognition, and attention are all requisites to making a CAPD diagnosis. The authors claim there can be some peripheral segregation of different related modalities. By evaluating auditory processing, language, cognition, attention, and motivation separately, problems in other modalities can be ruled out and can lead to a more definitive diagnosis of CAPD.

ASHA (1996) asserts, however, that "modality specificity, as a diagnostic criterion, is ‘neurophysiologically untenable.’" ASHA also claims that their are no "entirely compartmentalized areas in the brain that are solely responsible for a single sensory
modality.’" In other words, ASHA believes that there is no way to test modalities separately. In the community of healthcare providers, there is still no general consensus.

What do you think ... is it possible to assess modalities separately or is that unattainable?

http://search.ebscohost.com/login.aspx?direct=true&db=ehh&AN=19814809&site=ehost-live

Week 1, Fall 2007

On Tuesday, I saw one client who was an avid hunter. He was visiting the clinic in order to obtain custom ear protection in order to preserve his hearing during recreational shooting. At the time of the visit, the client did not wish to have his hearing evaluated, but he stated that he had no difficulty hearing in normal listening situations. No previous head or neck surgeries or other outstanding case history information were noted.

Otoscopy revealed minimal cerumen bilaterally in the lateral portion of the external auditory canals (EACs). Slight redness was noted in the right EAC, but, otherwise, the EACs were normal bilaterally. Tympanic membranes were visible and intact bilaterally.

Two sets of bilateral earmold impressions were taken at the time of the visit. The client ordered custom ear protection with a "sonic valve" designed specifically for hunters. The supervisor also discussed with the client the efficacy of ear protection during shooting and hunting.

The following article "Firearms and Hearing Protection" describes the efficacy of several types of hearing protection, including electronic hearing protection. The authors found the peak SPLs of several different firearms and compared the effects of various ear protectors. Measurements of the protected and unprotected noise levels at the ear were made while different hearing protectors were put on the mannequins. The effectivess of the different ear protectors were compared to each other. Then, NIOSH formulas for allowable noise exposure were calculated. The authors found that electronic hearing protectors alone could not respond quickly enough to attenuate enough sound to prevent inner ear damage. However, when electronic ear protectors and standard foam ear plugs were used together, gunfire was attenuated to safe levels.

But ... Would you wear double ear protection in the woods in WV???
http://www.hearingreview.com/issues/articles/2007-03_06.asp

Here is the link for the attenuation information for the type of custom electronic ear protection that my client ordered.
http://www2a.cdc.gov/hp-devices/selectprd.asp?PgName=EarPlug&Company=Westone+Laboratories&prodname=Westone&model=39

For a comparison, here is the link for the attenuation information for a swimmers' earplug.
http://www2a.cdc.gov/hp-devices/selectprd.asp?PgName=EarPlug&Company=Westone+Laboratories&prodname=Westone&model=AquaNot

Check out the NRR (Noise Reduction Rating) on each!