«National Vision and Hearing Screening Protocols Revised 2014 Citation: Ministry of Health. 2014. National Vision and Hearing Screening Protocols: ...»
Tympanometry: Middle-ear screens involve the placement of rubber tip at the opening of ear canal. (Note: Tympanometry is not performed on children with discharging ears, or where the skin is broken or inflamed).
Procedures During screening – Change to a clean and unused rubber tip between each child screened.
• Back at base – Ensure all used tips are wiped clean and any debris (eg, ear wax) removed and • placed in the dish of Milton solution. The tips should be totally submerged in the solution so that all surfaces are covered. After the required soaking period, (manufacturer’s recommendation) the tips should be left to drain onto clean absorbent tissue. When dry, they should be stored in their covered containers.
Personnel: Where VHTs have cuts or abrasions of the skin that may be susceptible to infection (ie, to the hands) it is advisable to wear disposable plastic gloves. Regular hand washing during screening is recommended. Where there is no access to a hand-basin, a topical antibacterial solution handrub or similar is suitable.
National Vision and Hearing Screening Protocols
Suggested cleaning products are:
alcohol swabs: two-ply – medium grade (saturated with 70 percent isopropyl alcohol) in • sterile individual packages handrub: Microshield Handrub (containing chlorhexidine gluconate 0.5 percent w/v in • 70 percent v/v ethanol) or similar.
8 National Vision and Hearing Screening Protocols Pathway 1: Initial screening audiometry (sweep test) or rescreen The procedure for initial screening (also known as the sweep test) is based on the American Speech-Language-Hearing Association screening guidelines (ASHA 1997). The technique relies on a conditioned response to sound. The screen is difficult for children under three years of age or children with developmental or behavioural problems – note that these children should be referred for audiological assessment. The success of the screening test depends on achieving a conditioned response.
Preparing the child for Initial screening audiometry (conditioning) Bring the child close to the audiometer (child must be no more than 30 cm from the headphones) and explain that you will be playing a simple game. Tell the child that you will be making some sounds or beeps with the machine.
Leave the headphones on the desk with headphones facing toward child.
Demonstrate with a 1000 Hz tone at 100 dB.
Explain to the child that, to play the game, each time they hear a beep they must drop a pebble into the container.
Repeat presentation of tone 1000 Hz, at 100 dB and drop another pebble into the container at the sound of the tone. Repeat this a few times, and vary the presentation time between each beep so that the child understands that they must wait for the sound.
The child should then be able to demonstrate that they are able to drop a pebble at the sound of the tone. The child must repeat this a few times to show they thoroughly understand the task.
If the child is unable to sit still and participate, then they are not ready to be screened and will need to be put on a rescreen schedule. If the VHT has concerns about their hearing, they should be referred to an audiologist for an audiometric assessment, using techniques that are more appropriate for the child’s developmental age.
When the child is fully conditioned and ready to begin the test, follow the procedure set out below.
Procedure for Initial screening audiometry The flowchart for this pathway is shown in Figure 1.
IMPORTANT! Reduce the intensity level of the tone from 100 dB to 40 dB. Failure to reduce the sound level may cause pain or discomfort to the child.
Place the headphones on the child and present a 1000Hz tone at 40 dB in the right ear. If the child responds, present a 1000 Hz tone at 40 dB in the left ear.
If the child responds, present a 2000 Hz tone at 20 dB.
• If the child responds, present a 4000 Hz tone at 20 dB.
• If the child responds, present a 500 Hz tone at 30 dB. (Note increased level.) • If the child responds to all these tones, then test the left ear in the same way, starting with the 500 Hz tone at 30 dB.
Possible outcomes for the screen Formal hearing screening as part of the WCTO Schedule is undertaken at four years of age as
part of the B4 School Check. This screen has four possible outcomes:
Not tested because unable/unwilling to participate. If the child is unable to participate, note • the result as ‘not tested’, record the result as a ‘rescreen’ and rescreen the child in three months’ time.
Pass. If the child hears audiometry screening levels of 20 dB at 1000, 2000 and 4000 Hz • and 30 dB at 500 Hz bilaterally, record the child’s hearing test as a ‘pass’.
Rescreen. If the child hears 40 dB bilaterally at 1000 Hz, but does not respond to the next • or any other tone, record the result as a ‘rescreen’.
Refer. If the child does not respond to 40 dB in either the right or the left ear at 1000 Hz, the • result is a ‘refer’. (Document this as ‘40dB not achieved’ in referral or record as 40 dB.) Procedure for each outcome The child is unable to participate. If the child is unable to participate the result is not 1.
tested. Arrange a repeat of initial test in three months’ time. If the child is unable to participate on the second attempt, they should be referred to an audiologist for an audiometric assessment, using techniques that are more appropriate for the child’s developmental age.
The child passes all tones bilaterally. If the child responds to all tones presented to 2.
both ears, the result is a pass and no further action is required. Record the result of the screening test in the B4 School Check database. If the child is over five years, one week of age then the result should be recorded in the ENROL database only.
The child responds at 40 dB bilaterally but fails lower-intensity tones. If the 3.
child responds at 40 dB bilaterally, and then does not respond to the next or any of the following tones, the screen result is a rescreen.
Stop the test and record the result as a rescreen and undertake tympanometry. The child should be rescreened within three months using Pathway 1 Initial screening audiometry (sweep test) or rescreen, or Pathway 2 Screening audiometry (hearing concerns) at the discretion of the VHT Note: If there are concerns about speech/language, development or behaviour or any risk factors (see Table 1), the child should be referred (see below). The preschool and parents/caregivers of children who require a rescreen should be notified when a rescreen is scheduled.
10 National Vision and Hearing Screening Protocols The child does not respond to 40 dB in either ear. If the child does not initially 4.
respond at 40 dB in either the right or the left ear, the screen result is refer.
Record the result as refer and undertake tympanometry.
The child’s hearing must be tested following treatment by GP or ear nurse to rule out an • underlying sensorineural hearing loss. It is the responsibility of the GP or ear nurse to arrange this test with an audiologist.
Table 1: Risk factors for hearing related developmental and learning difficulties
• Permanent hearing loss independent of otitis media with effusion. Provided these children have already been identified and are being cared for, they should not be part of the screening programme but should be entered in the statistics.
• Suspected or diagnosed speech and language delay.
• Autism spectrum disorder or other pervasive developmental disorders.
• Syndromes (eg, Down Syndrome) or craniofacial disorders that include cognitive, speech and language delays.
• Blindness or uncorrectable visual impairment.
• Cleft palate with or without an associated syndrome.
• Developmental delay.
• Significant socioeconomic disadvantage.
Recording of results The results and outcomes (ie, not tested, pass, rescreen or refer) for B4 School Check audiometry must be recorded in the B4 School Check database and/or ENROL database, depending on the age of the child. The Ministry of Education ENROL database is now getting regular updates from the B4 School Check database. However, where children are unmatched or start school without having had a B4 School Check, their results will need to be manually entered on ENROL.
National Vision and Hearing Screening Protocols Pathway 2: Screening audiometry (hearing concerns) A child’s parent/caregiver or teacher may occasionally have concerns about the child’s health, development, behaviour or learning and wonder whether a hearing problem is causing these symptoms or difficulties. Sometimes an older child will complain of hearing difficulties or hearing-related symptoms such as tinnitus or balance problems.
Those requesting a hearing test should be informed that screening is not a full diagnostic hearing assessment, and a child should be referred to an audiologist if there are ongoing concerns. The results and outcomes must be recorded in the ENROL database.
This is the appropriate screening test to be undertaken if a child is referred with concerns about a possible hearing loss. However if the child has poor concentration skills, it may be necessary to offer Pathway 1 Initial screening audiometry (sweep test) (Figure 1).
The flowchart for Pathway 2 Screening audiometry (hearing concerns) is shown in Figure 2.
This test protocol may also be used by the VHT who is undertaking a rescreen following a ‘Refer’ at an initial screen.
Note: All children on initial screen should be tested with initial screening (sweep) audiometry (Figure 1) unless the test is a hearing concern.
Screening audiometry may assist GPs, ear nurses and audiology clinics to triage waiting lists for those children awaiting further assessment.
Procedure for Pathway 2: Screening audiometry (hearing concerns) The screen has two steps. The first step is to familiarise the child with the screening tones. Once that is achieved, the VHT should begin the test and record the child’s responses.
Familiarisation is undertaken to make sure that the child is able to reliably perform the response task. The child must be presented with a signal loud enough to evoke a clear response. Prepare the child for screening in the same way as in the initial screening (sweep test) audiometry, then proceed as follows.
Screening determination The level of hearing is defined as the lowest decibel hearing level at which a response reliably occurs. The tones to be used are 1–2 second duration pure-tone stimuli at 500, 1000, 2000 and 4000 Hz.
Note that the minimum levels to be tested to are: 25 dB at all test frequencies except 500 Hz at 30 dB.
12 National Vision and Hearing Screening Protocols Screening procedure
1. Place the headphones on child.
2. Start at 1000 Hz at 40 dB and reduce intensity in 5 dB steps until the child passes at 25 dB, or record last response.
3. Present next tone at 2000 Hz at 40 dB, and continue test sequence. That is, reduce intensity in 5 dB steps until the child passes at 25 dB, or record last response.
4. Repeat steps at 4000 Hz and 500 Hz (minimum 30 dB).
5. Switch to left ear and repeat test, beginning at 500, 1000, 2000 and 4000 Hz at 40 dB.
6. If the child does not respond at 40 dB, record this result (40dB) and present tone at next frequency (Hz).The practitioner is required to complete the test. This result is refer: (see Referral pathways).
7. Proceed to tympanometry screening and enter the results onto the Ministry of Health’s B4 School Check database or the Ministry of Education’s ENROL database. Refer these children as per the clinical pathway and referral criteria in Screening audiometry shown in Figure 2.
Screening audiometry (hearing concerns) – pass result If the child responds at passing level, as shown in Table 2, enter the results onto the Ministry of Health’s B4 School Check database or the Ministry of Education’s ENROL database. No further action is required.
Table 2: Sequence of screening frequencies and pass levels
Referral pathways The VHT will need to provide a copy of the results of the audiometry test as shown in Table 2, tympanometry (if required), and any relevant observations of the child back to the person who requested the audiometric assessment.
Referral pathways can vary according to local requirements, but in general referral for suspected sensorineural losses should be made to audiology, and for suspected conductive loss to a GP or ear nurse where they are available. However, it is important to recognise that a sensorineural hearing loss may be masked by a conductive loss, and the conductive loss must be treated and the child retested once this has resolved.
Key to flowchart symbols Figure 1: Pathway 1 – Initial screening (sweep) or rescreen audiometry clinical pathway 14 National Vision and Hearing Screening Protocols Figure 2: Pathway 2 — Screening audiometry (hearing concerns) clinical pathway National Vision and Hearing Screening Protocols Screening technique: tympanometry Children who are having tympanometry must have first had audiometry screening. Normal audiometry (ie, bilateral pass responses) means no further screening needs to be done. The tympanometry procedures below all follow an abnormal screening test, with the following exception: in some district health boards, targeted tympanometry screening of groups at high risk of harm from glue ear is undertaken.
Tympanometry screens for middle-ear function, and involves the placement of rubber tip at the opening of ear canal.
Note: Tympanometry should not be performed on children with discharging ears, or where the skin is broken or inflamed. These children should be referred for treatment and rescreened when their condition is treated.