Evaluation of pure tone audiometry and impedance screening in infant school

children

Abdulwaris Khan (11110031) Omar haj Okod (10110073)

Hamad Emad Thuhayr (10110067) Mohammed Sulaiman (10110060)

Sameer Mamoon Haj Omar (9110024) Jihad Al-Shabaan (11110014)

2013/2014

Multi CAT (diagnosis)

Abstract of the study Objective:

1. To evaluate impedance measurements VS. pure tone audiometry as a screening program for the detection of middle ear changes associated with hearing loss in infant school children.

2. To estimate the costs to the health authority of each method.

Design:Two stages were involved:

o Pure tone audiometry carried out by nurses.o Impedance screening by physicians.

Setting: 18 infant or primary schools in Langbaurgh, Cleveland, UK.

Participants: 610 previously unscreened infant school children took part in the study.

Measurements and main results:1. The sensitivity and the predictive value of a positive test in two

stage impedance screening was markedly superior to that of pure tone audiometry.

2. The specificity was similar using the two methods. 3. the impedance method was more rapid and estimated to consume

less resource as a screening procedure than pure tone audiometry.

Conclusion: The superiority of the use of impedance screening established in this study should be confirmed in a subsequent audit carried out purely by school nurses.

Abstract of the study

STEP 1: Are the results of the study

valid?

• Six year old schoolchildren in 18 infant schools in Langbaurgh, Cleveland, UK were the potential entrants to the study.

• Children already known by the school nursing service to have middle ear disorders were excluded from further study.

• The answer is YES!!!

Q1: Was the diagnostic test

evaluated in a representative

spectrum of patients?

Q2: Was the reference

standard applied regardless of

the index test result?

• The reference standard for diagnosing hearing loss is pure tone audiometry which was applied for all infant school children.

• Impedance measurements is an alternative method in which it does not lead the diagnosing of hearing loss directly but it measures the resistance to sound by the middle ear and its contents. However, disorders of the middle ear may lead to established hearing loss. It was also performed in all samples.

Q3: Was there an independent, blind

comparison between the index test and an

appropriate reference “gold standard” of

diagnosis?

• The results of the alternative method were not known to the respective operators.

• Impedance were conducted by physicians in relevant schools.• Pure tone audiometry were conducted by 9 school nurses in

all 18 schools chosen.

STEP 2: What were the results?

• This table illustrates the number of identified cases in either the two methods or one method and the number of unidentified cases. This table contains the numbers of the first stage.

Q1: Are test characteristics

presented?

This table illustrate the number of

infants who were screened by

Pure Tone Audiometry (PTA)

measurements.

This table illustrate the number of

infants who were screened by

Impedance measurements.

This table illustrate the sensitivity, specificity and positive predictive value of PTA and Impedance tests.

This table illustrate the costs of the two tests PTA and Impedance.

STEP 3: Applicability of the results.

Q: Were the methods for

performing the test described

in sufficient detail to permit

replication?• Yes. It was described in the first 5 slides.• The screening test that was recommended by the authors is the Impedance

measurements. The reasons they stated are:o Only three Impedance tympanometers would be required for the annual testing of hearing loss in

infant school children in the catchment area. PTA measurements require 14 audiometers.o It will cost less than PTA measurements.o It is more comfortable test than OTA because of:

• The ease of performing it.• It requires less time compared with PTA measurement.• The cooperation of the child will not be a problem during the test.