CONWY
& DENBIGHSHIRE NHS TRUST
Directorate
of Clinical Support Services
AUDIOLOGY
UNIT
Audiology
Procedure for Speech Audiometry.
Author: Wilkinson, A.S.; Doran, M. Department:
Audiology
Number of sections:
Date validated: 11.03.2003 Validating body: Senior Staff
Reviewer: Head of Department
Updated None
Review Date: 11.03.2004
DESCRIPTION: A functional test of ear-specific speech discrimination performance, in terms of optimal levels, to be compared to both normative data and the patient’s pure tone audiogram.
LOCATION: Audiology Department test room.
PATIENT CATEGORY: Patients aged 16 years and above, presenting with speech comprehension difficulties, with or without a suspected non-organic component to a hearing loss, referred by E.N.T. Medical Staff.
PROTOCOLS: HUMAN RESOURCES: Qualified Audiological Scientist or Senior Audiologist (or above).
APPOINTMENT TIME: 80% of patients to be offered an appointment with four weeks of receipt of referral.
WAITING TIME: 80% of patients to be seen within twenty minutes of their appointment time with an explanation given for any delay.
TEST DURATION: Up to one hour.
SET-UP EQUIPMENT:
Clinical audiometer
CD player
CD comprising AB(S) word lists (under licence)
Local normative data
PATIENT MANAGEMENT:
(1) BRIEFING: Patients will be fully informed of the nature of the procedure.
(2) PATIENT INSTRUCTION: Patients will be informed that this is a form of hearing test, and that they will be required to repeat spoken material.
(3) PATIENT DEBRIEFING: Patients will be informed that results will be analysed, and a report sent to the referring Consultant.
PRODUCT METHOD:
1. Conduct full pure tone audiogram (PTA) and establish uncomfortable loudness levels (ULLs) bilaterally.
2. Set up audiometer for speech audiometry:
select menu-5-menu-speech-air-left-CD-air mask-SN as prompted. Use L/R shift
if required. (For Test 3, simply select menu-3).
3. Insert AB word lists CD into CD player on top of audiometer.
4. Calculate initial dial and masking settings for each ear:
Speech setting = eHPL+19 dB
Masking setting = Mw+Ds-9-BBCnt
where: eHPL = average of best two AC thresholds for test ear in range
250 Hz to 4 kHz
Mw = threshold for speech noise in non-test ear
Ds = speech dial setting
BBCnt = best BC threshold in non-test ear
5. Instructions: ‘You are going to hear someone speaking
single words through the earphones, one at a time. The words are spoken slowly
like this, ‘BUS…FUN…SHOP’. At the beginning the words will be at a comfortable
level, but they will gradually become quieter and finally louder. Please listen
carefully and repeat after each word what you think you have heard, even if it
is only part of the word. Ignore any sounds that may be present in your other
ear’.
6. Set ‘hearing level’ and masking noise to levels set out in (4). Switch masking noise ‘on’, and play CD (starting at Track 1).
7. Score correct number of phonemes for each word.
8. When word list finishes (10 words), reduce both speech/masking settings by 10 dB.
9. Repeat until total score for word list is less than 10%.
10. Present at 20 dB above initial settings, and repeat until ULLs have been reached.
11. Continue for other ear (use L/R shift on audiometer).
12. Calculate optimal discrimination score (ODS), and draw best fit sigmoid through graph of dial setting vs. score. From 50% ODS, determine half-peak level (HPL) dB for each ear.
13. Calculate half-peak level elevation (HPLE) for each ear = HPL - HPLn
where: HPLn = normal HPL for that equipment (subjective calibration curve)
14.Compare ODS and HPLE with PTA for each ear, and investigate possibility of ‘roll-over’ effect.
15.Remove CD and reset audiometer.
STANDARDS:
LOCAL:
All staff and procedures must conform to the Trust’s General Policies and Procedures:
http://www.cd-tr.wales.nhs.uk/polproc/2000_launch/welcome.htm
NATIONAL: Audiometers are calibrated to BS 2497 Part 5:1988 for AC and BS 6950:1988 for BC, traceable to the National Physical Laboratory Measurement Standards.
Tests are conducted in sound treated rooms complying with Department of Health and Society Security Engineering Division Standards (1976).
Sound-proof rooms comply with Department of Health and Society Security Directorate of Works Operations Audiology Test Room Qualification Report NAS11/.
Routine surveillance of equipment complies with DHSS B700.
Results are correctly documented in accordance to BSA Guidelines (British Journal of Audiology 23, 265-266).
Health and Safety at Work, etc. Act, 1974, is implemented.
WHC (80)10 Confidentiality of Medical Records is implemented.
AUDIT OF QUALITY
INTERNAL: Every six months, the length of time patients wait to be seen will be monitored and the results made available for external audit.
AUDIT OF QUALITY
EXTERNAL:
APPENDIX 1: Biological calibration (as of January 2002)
Half-peak level (Audiology Test room 1/2/3): 22 dB HL
Half-peak level (Audiology Test room 4): 24 dB HL