by Brian Taylor, AuD, Editor-at-Large
Healthcare professionals worth their salt know their clinical decisions often rely on the availability of high-quality research, as well as their ability to interpret and consume it.
Below is a smattering of recently published audiology research that should garner the attention of conscientious clinicians.
How Hearing Loss and Education Level Affects Cognitive Screening
Most hearing care professionals are keenly awareness of the linkage between hearing loss and cognitive decline in older adult patients. Look no further than this 2017 Lancet report on how several modifiable factors, including hearing loss fit into the larger picture of prevention and treatment of dementia, if you need to get up to speed on the topic.
Laura Gaeta and colleagues studied the effects of reduced audibility on a group of adults between the ages of 60 and 80. In their study, published in the Nov/Dec 2019 issue of JAAA, they compared the scores on the Mini-Mental State Exam (MMSE), probably the most commonly used cognitive screener in two groups: Older adults with mild to moderately severe hearing loss (and a mean Quick SIN score of 7.95) and a group of younger adults with normal hearing who served as the control. Both groups were administered a recorded version of the MMSE at a relatively easy +25 SNR. Also, the control group was given a filtered version of the MMSE to approximate the hearing loss experienced by the older adult participants.
Their analysis of the results showed no significant differences between the older adults (actual hearing loss) and younger adults (simulated hearing loss), indicating that poor audibility is the primary reason for the decreased MMSE scores. Further, the researchers found that education level was the only significant modifier in the relationship between the two groups of study participants.
Results demonstrate that the presence of a hearing loss should be confirmed (and amplification provided) before administering the MMSE or other similar cognitive screeners. Additionally, the education level of the person being screened needs to be considered as the MMSE is biased toward those with lower levels of education.
Given these findings, individuals with lower levels of education and untreated hearing loss are more likely to be overdiagnosed with cognitive impairments. Lastly, the findings of this study underscore the critical role audiologists play within the entire healthcare system in raising the awareness of hearing loss (and use of amplification) in identifying patients with dementia, with an aim toward early diagnosis and remediation.
The Unaided SII as a Risk Factor for Language Delays
The January 2020 issue of JSHR has a thought-provoking article on the relationship between aided audibility and language development in children with hearing loss. Boystown’s Ryan McCreedy along wth several colleagues looked at the relationship between unaided hearing and language outcomes in a group of children with hearing loss who did not wear hearing aids with the aim of developing audibility-based hearing aid candidacy criteria.
The researchers examined the unaided hearing and language outcomes in 52 children with mild-to-severe hearing losses. A group of 52 children with typical hearing matched for age, nonverbal intelligence, and socioeconomic status served as a control.
The researchers used two audibility-based criteria:
- The level of unaided hearing where unaided children with hearing loss fell below the median for children with typical hearing
- The level of unaided hearing where the slope of language outcomes changed significantly based on an iterative, piecewise regression modeling approach.
They found that the level of unaided audibility for children with hearing loss that was associated with differences in language development from children with typical hearing or based on the modeling approach varied across outcomes but converged at an unaided speech intelligibility index (SII) of 80. Thus, unaided SII could be used as a clinical criterion for hearing aid fitting candidacy for children with hearing loss, as children with an unaided SII value of less than 80 may be at risk for language delays.
Recurrence Patterns in Sudden Hearing Loss
Sudden sensorineural hearing loss (SSNHL) is understandably alarming for patients, but is distressing for clinicians, too. According to the Academy of Otolaryngology, SSNHL is defined as a 30-dB or more reduction in hearing thresholds over at least three consecutive frequencies within 72 hours. SSNHL affects five to 20 per 100,000 people per year. In most cases the cause of SSNHL remains unknown. Treatment of SSNHL is generally empirical with corticosteroids representing the most common solution.
A recent retrospective study, published online January 15, 2020 by the American Journal of Audiology, evaluated the recurrence rate of SSNHL and analyzed its correlation with clinical and audiometric characteristics. The researchers, led by Giancarlo Pecorari at the University of Turin in Italy studied 73 patients with idiopathic SSNHL.
The researchers found 2- and 5-year recurrence rates were 5.60% and 10.34%, respectively.
Mean time lapse between 1st episode and recurrence ranged between 2 and 81 months and approximately 70% of patients had a partial recovery at recurrence. The same ear was affected in 42.8% of patients, the contralateral ear was affected in 42.8% of patients, and recurrence was bilateral in 14.4% of cases. Recurrence correlated only with the presence of tinnitus during follow-up.
Based on a limited number of participants (7) with recurring SSNHL, 85.7% of cases (6/7) had a flat loss, no average hearing loss was > 70 dB HL, all cases had tinnitus, and 71.4% of patients (5/7) experienced a partial recovery. Further, recurrence affected the same ear in 42.8% of patients (3/7) and the contralateral ear in 42.8% of patients (3/7), and it was bilateral in one case (14.4%). Although this study suggests recurrence rates are relatively low, given the potentially harmful long-term consequences of SSNHL, hearing care professionals must be aggressive in their referral for medical intervention.