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Six year effectiveness of a population based two tier infant hearing screening programme
S A Russ1, F Rickards, Z Poulakis
1Centre for Community Child Health, Royal Children's Hospital, Melbourne, Australia.
Insights
The Victorian Infant Hearing Screening Program (VIHSP) lowered the median age of diagnosis for severe congenital hearing impairment (CHI) in infants. However, the overall impact on early diagnosis rates for all levels of CHI was disappointing.
Area of Science:
- Audiology
- Public Health
- Pediatrics
Background:
- Congenital hearing impairment (CHI) affects infant development.
- Early diagnosis and intervention are crucial for managing CHI.
- Universal infant hearing screening programs aim to improve early detection rates.
Purpose of the Study:
- To evaluate the effectiveness of the Victorian Infant Hearing Screening Program (VIHSP) in reducing the median age of diagnosis for bilateral congenital hearing impairment (CHI) greater than 40 dB HL.
- To compare diagnosis ages and rates between pre- and post-implementation cohorts of the VIHSP in Victoria, Australia.
Main Methods:
- A comparative study of infant birth cohorts from 1989 (pre-VIHSP) and 1993 (post-VIHSP) in Victoria.
- The VIHSP employed a two-tier approach: risk factor ascertainment and universal distraction testing.
- Auditory brainstem evoked response (ABR) was used for high-risk infants, while others received distraction testing.
Main Results:
- The median age of diagnosis for CHI >40 dB HL decreased from 20.3 months (1989 cohort) to 14.2 months (1993 cohort).
- A significant increase in the diagnosis of severe CHI by 6 months of age was observed (21.7% in 1993 vs. 6.3% in 1989).
- Despite improvements in severe cases, overall results for moderate and profound CHI were disappointing, with no significant reduction in median diagnosis age.
Conclusions:
- The VIHSP successfully lowered the median age of diagnosis for severe congenital hearing impairment.
- The program facilitated earlier diagnosis for a greater number of infants with severe CHI.
- Overall program outcomes were considered disappointing, indicating a need for further improvements in early CHI detection.
Aims:
To determine whether a two tier universal infant hearing screening programme (population based risk factor ascertainment and universal distraction testing) lowered median age of diagnosis of bilateral congenital hearing impairment (CHI) >40 dB HL in Victoria, Australia.
Methods:
Comparison of whole population birth cohorts pre and post introduction of the Victorian Infant Hearing Screening Program (VIHSP). All babies surviving the neonatal period born in Victoria in 1989 (pre-VIHSP) and 1993 (post-VIHSP) were studied. (1) Pre-1992: distraction test at 7-9 months. (2) Post-1992: infants with risk factors for CHI referred for auditory brain stem evoked response (ABR) assessment; all others screened by modified distraction test at 7-9 months.
Results:
Of the 1989 cohort (n = 63 454), 1.65/1000 were fitted with hearing aids for CHI by end 1995, compared with 2.09/1000 of the 1993 cohort (n = 64 116) by end 1999. Of these, 79 cases from the 1989 cohort (1.24/1000) and 72 cases from the 1993 cohort (1.12/1000) had CHI >40 dB HL. Median age at diagnosis of CHI >40 dB HL for the 1989 birth cohort was 20.3 months, and for the 1993 cohort was 14.2 months. Median age at diagnosis fell significantly for severe CHI but not for moderate or profound CHI. Significantly more babies with CHI >40 dB HL were diagnosed by 6 months of age in 1993 than in 1989 (21.7% v 6.3%). Compared to the six years pre-VIHSP, numbers aided by six months were consistently higher in the six years post-VIHSP (1.05 per 100 000 births versus 13.4 per 100 000 births per year).
Conclusions:
VIHSP resulted in very early diagnosis for more infants and lowered median age of diagnosis of severe CHI. However, overall results were disappointing.