Osicus User Guide
Contents
1. 1 666nnnnnnnnena 26 5 3 Hearing Test Procedure sivescssscsssansaivancssanndesassosdevoncousasss sanndvaneiausans 27 5 4 End User LiCenS eas tama amil 29 1 Introduction Thank you for choosing the Asra Osicus Solo audiometer The Osicus Audiometer is intended for use in industrial and corporate settings for the screening of hearing It is anticipated that at a minimum a trained competent person or an audiometrician will use the audiometer to conduct hearing testing Along with this manual you should find the following items in the box e Asound module e Aset of headphones e A response switch e A USB cable e A CD ROM e An Installation Manual In addition to these items you will need e APCor laptop The PC or laptop will need to have a spare USB port to connect to the sound module and be running a Microsoft Windows operating system Windows 2000 XP Vista or Windows 7 to run the Osicus Audiometer control software The following chapters will introduce you to setting up the device and the software and its operation starting with helpful displays that visually guide you through the different functions 10 2 Preparing the System The following displays are designed to help you use the main features of the Asra Osicus software 2 1 Starting the program You will find an icon on your desktop and by clicking on START AII Programs with the title Osicus Solo Clicking on this will start the program 2 2 Introducing2. ASRA OSICUS AUDIOMETER USER MANUAL ASRA OSICUS AUDIOMETER USER MANUAL V1 25 March 2010 GM Instruments Ltd Unit 6 Ashgrove Ashgrove Road Kilwinning KA13 6PU United Kingdom Tel 44 0 1294 554664 Fax 44 0 1294 551154 Email gminstruments aol com or enquiries gm instruments com web www gm instruments com Asra Osicus Audiometer User Manual C 2010 GM Instruments Limited Reproduction transfer distribution or storage of part or all of the contents in this document in any form without the prior written permission of GM Instruments Limited is prohibited Asra Osicus is a trademark of GM Instruments Limited Other product and company names mentioned herein may be trademarks or trade names of their respective owners GM Instruments Limited reserves the right to make changes and improvements to any products described in this document without prior written notice Under no circumstance shall GM Instruments be responsible for the loss of any data or income or any special incidental conseguential or indirect damages howsoever caused The contents of this document are provided as is Except as required by applicable law no warranties of any kind either expressed or implied including but not limited to the implied warranties of merchantability and fitness for a particular purpose are made in relation to the accuracy reliability or contents of this document GM Instruments Limited reserves the right to revise th
3. Tests Audiograms Predictive Analysis Name Gender Male ID Number Date Of Birth 01 January 1980 Fig 3 1 1 When you click on New a screen which allows the entry of Name Gender ID Number and Date of Birth is offered Name Enter details as First name Last name Gender Use the menu to select ID Number Letters or numbers are accepted for entry but as the content of this field is used as the unique identifier for the Asra Batch_Utility 15 software and Occupational Health Databases such as Opas or Cohort it is important to enter this detail carefully Date of Birth Use the menu arrow to display a calendar and set the date and month from this then highlight and type the year using 4 characters An example of a completed screen is shown below HOME NEW RUN TEST Details Tests Audiograms Predictive Analysis Name Sarah Stewart Gender Female ID Number 123 Date Of Birth 08 February 1948 Fig 3 1 2 16 3 2 Find Subject fe Find Person Search Files First Name Surname Personnel Number Date of Birth or Open File Change Directory Directory C audio results 1 Include Subdirectories Fig 3 2 1 The search can be based on the content of a particular folder directory and it s sub folders directories It can be done manually by clicking on browse or it can be done automati
4. nen Details Tests Audiograms Predictive Analysis Right Ear Left Ear HEH Hearing Level dB 30 0 25 0 5 1 2 8 4 amp 1 34 6 Freguency kHz Frequency kHz HSE Category 2 WARNING Mild Hearing Impairment Left ear Additional Notes Audiograms User Comments Clear Update M Fig 3 2 4 Below the audiogram is shown the HSE Category HSE Categories are explained further in Appendix A To print the audiograms click on the Print button 3 3 Comparison of Audiograms To compare the selected audiogram with another click the Compare Audiograms button A further window will open to allow you to select the audiogram to be compared with the previously selected one Highlight the one you want and then click on the Select button Both will then be shown superimposed 19 3 4 Predictive Analysis Predictive Analysis is one of the unique features of the Asra Osicus software Hearing test data can be analysed by intelligent algorithms and future hearing trends can be predicted The predicted audiogram shows how the intelligent analysis thinks the subject s audiogram will look in a year s time It assumes no change in hearing protection or in the current working noise environment Although analysis is made to the highest possible standards there is no guarantee that the prediction is accurate because many factors could inf
5. category 1 is assigned If the sum for either ear equals or exceeds the warning level an HSE category of 2 is assigned If the sum for either ear equals or exceeds the referral level the HSE category is upgraded to 3 The sum of the results at 3kHz 4kHz and 6kHz for each ear are compared with those for the last hearing test recorded for the employee If there is an increase in hearing threshold level of 30dB or more this indicates rapid hearing loss and an HSE category of 4 is assigned Next the sum of the results at 1kHz 2kHz 3kHz and 4 kHz for each ear are compared A difference of 40 between ears indicates unilateral 24 hearing loss This suggests a problem due to disease or infection This does not affect the HSE category The definitions and actions for each HSE category are detailed in table A2 below Category Calculation Action 1 ACCEPTABLE HEARING Sum of hearing levels at 1 None ABILITY 2 3 4 and 6 kHz Hearing within normal limits 2 MILD HEARING Sum of hearing levels at 1 Warning IMPAIRMENT 2 3 4 and 6 kHz Compare Hearing within 20 percentile value with figure given for i e hearing level normally appropriate age band and experienced by 1 personin5 gender in Table A1 May indicate developing NIHL 3 POOR HEARING Sum of hearing levels at 1 Referral Hearing within percentile 2 3 4 and 6 kHz Compare i e hearing level normally value with figure given for experienced by
6. kHz 2 from 3 6 kH2 3fom5 8 kHz A Random Interval 1 Start Ear Required to calculate Left HSE categories O Right Allow user to change settings Fig 2 5 The location of the Calibration File and location where audiograms generated will be Saved are specified here Note that if you wish to analyse audiograms generated by different groups of workers either from the same company or from different companies using the optional Asra Batch_Utility software you should create a folder for each group and set the appropriate folder using this screen prior to testing Other test settings such as the frequencies tested the tone characteristics the threshold determination criteria and order of ear testing can all be altered from within this dialogue Shortening the test time increases the possibility that the subject will be able to retain concentration for the duration of the test and O therefore produce the most favourable and accurate result We recommend testing the frequencies listed above with a tone length no greater than 1 5 seconds and a threshold search criteria based on 2 from 3 responses 14 2 6 Tester Information Tester Details Name John Brown Company GM Instruments Ltd Fig 2 6 Enter the name ofthe person who will be doing the tests and the company they represent 3 Subject Details 3 1 New Subject HOME FIND RUN TEST DAR o ZET Details
7. 1 person in 20 appropriate age band and Suggests significant NIHL gender in Table A1 4 RAPID HEARING LOSS Sum of hearing levels at 3 4 Referral Reduction in hearing level of and 6 kHz 30dB or more within 3 years or less Such a change could be caused by noise exposure or disease UNILATERAL HEARING LOSS Sum of hearing levels at 1 Referral Suggesting a problem due to 2 3 and 4kHz for both ears disease or infection If the difference between the ears is greater than 40dB the individual should be advised of the findings Table 5 1 2 The HSE Categorisation Scheme NIHL Noise Induced Hearing Loss Reference HSE Controlling Noise at Work The Control of Noise at Work Regulations 2005 pg 118 8 119 25 5 2 Appendix B Cleaning Maintenance and Storage Cleaning The sound module of the Asra Osicus Audiometer can be cleaned with a damp cloth or light solvent Water or fluids should not be allowed to enter the case or the internal electronics may be damaged The headphones and audiocups should be cleaned regularly for hygiene purposes It is recommended that they be cleaned between each test An antiseptic tissue wipe is best used for this purpose Carefully wipe the headphone surface and the rim of the audiocup and allow to dry Do not apply pressure to the headphones themselves or this may damage the springs supporting them Maintenance The sound module should be calibrated at least once a year Con
8. 6143 Date of Calibration 03 02 2010 Calibration File C 4audio Calibration409 009 10 tst Fig 2 4 Viewing this screen allows you to check that you are using the correct audiometer earphone combination and that the calibration file is up to date An audiometer is calibrated with one set of headphones The audiometer number and matching headphone numbers are stored during audiometer setup The audiometer should only be used with the headphones used during calibration If the audiometer number is incorrect click on the Change button then select the correct audiometer from the list If the audiometer is not listed then its details must be added by loading in a new calibration file Now click on OK to move to the next screen To guarantee accuracy each audiometer must be calibrated at least once each year and receive an exhaustive calibration every two years The date of last calibration is displayed with the audiometer details After calibration you will be supplied with a file containing calibration information To update the calibration information press the Change button browse to this file and click on Ok 13 File Settings Calibration File C 4audio Calibration409 009 10 tst Save Directory C 4audio wesults Test Settings Frequency Selection Automatic Hearing Test Settings C 250 Hz Tone Length 15 500 Hz 1 kHz 2 kHz Start Level ro E dB HL 3 kHz Number of Matching Responses 4
9. B HL until response occurs Note this value Step 4 Repeat steps 2 and 3 until three responses out of a maximum of five trials occur at a single level 2 out of 3 also acceptable If less than three responses out of five trials are obtained at a single level present a tone at 30 dB HL then repeat the test procedure Step 5 Proceed to the next test frequency repeating steps 1 to 4 Finish all test frequencies at one ear Step 6 Repeat steps 1 to 5 for the second ear Step 7 Retest the first ear at 1 kHz If the results of the repeat measurement for that ear agree to within 10dB with those of the first measurement finish the test Record the lower of the two responses If 10dB or a larger deviation in hearing threshold level is discernible continue to 2 kHz 3 kHz etc until responses are within 10 dB Table 5 3 Hearing Test Steps 28 5 4 Appendix D End User License Agreement EULA END USER LICENSE AGREEMENT FOR ASRA OSICUS SOFTWARE GM Instruments Limited GM grants to you as an individual or as a legal entity Licensee a non exclusive indefinite license to install and use the number of copies of each version of Asra Osicus The Software as provided with the Asra Osicus Audiometer The Software includes computer software and any associated electronic or online documentation associated media and printed materials Licensee may not to attempt to modify reverse engineer decompile or disass
10. cally by entering the Surname or an ID Personnel Number An example of a search based on partial ID is shown below fe Find Person Search Files First Name Surmame Personnel Number Date of Birth Find Select or Open File E FileName PersonName IDNumber DateOfTest C 4audiotresults Eric Greig 31 03 2010 C 4audiotresults Eric Greig 3170372010 C taudio results Eric Greig 31703 2010 C 4audiotresults4 Eric Greig 14 02 2009 C 4audio results Sarah Stewart 23 30 06 2008 Change Directory Directory C audio results Include Subdirectories Fig 3 2 2 17 Having found the person you want highlight the entry and click on Select The screen shown below will then become available and you have the option of using the Details Tests Audiograms tabs to view the previously generated data NEW FIND RUN TEST EXI OverallHSEComment REFERRAL Poor Hearing Left and Right ears Fig 3 2 3 The details tab will show the Subject information entered The Tests tab will show all of the stored audiograms for the selected person If you want to view a particular audiogram select it and click on Display Test or click on the Audiograms tab An example of a completed audiogram brought back from saved records is shown on the following page 18 Set NEW HOME FIND RUN TEST
11. damage the springs supporting them Index T 15 10 2 Preparing the 11 2 1 Starting the Program 11 2 2 Introducing the Home Screen 11 2 3 Perform Machine Checks es 12 2 4 Select 13 Settings 14 2 6 Tester Ihfohim all Ohh 15 5 New and Find buttons 15 15 3 2 Find SUbjEE ummi 17 3 3 Comparison of 5 19 3 4 Predictive ANANVSI Siesta itovadakanv n ainena kuu 19 4 Running aaa 21 21 4 2 Manual 22 4 3 Audiograms H amp SE 22 LA m 23 5 PIO 24 51 SE Cale 24 5 2 Cleaning Maintenance and Storage
12. ectly Pre test Examination The tester should perform an otoscopic examination of the ear immediately before the test to detect any major abnormality or the presence of fluid or wax which may affect the results The tester should also be familiar with any hearing protection which may be used by workers so they can discuss proper fitting cleaning and maintenance Testing Procedure Test tones shall be presented with length of 1 to 2 seconds When a response occurs the interval between the tone presentations shall be varied randomly but shall not be shorter than the test tone duration If the test duration becomes too long or the test subject becomes distressed or uncomfortable the test subject should be given a rest period and the complete test started again 27 Familiarisation Present a test tone of 30 dB HL at 1 kHz to one ear If a response is not evoked increase the level in steps of 10dB until a response occurs Repeat for 2 kHz and 3 kHz This assures the tester that the test subject understands and can perform the response task Tones shall be presented in the seguence 1000 2000 3000 4000 6000 8000 500 to one ear followed by the same sequence to the other ear Step 1 Present a tone at 30 dB HL If no response increase the level by 10 dB HL until a response occurs Step 2 After the response decrease the level by 10dBHL until no response occurs Step 3 Increase the level by 5 d
13. emble the Software GMI will provide support for the Software for a period of 12 months from the date of invoice After that period you may continue to use the Software but will not be eligible for support from GM for the Software Continued support and software updates may be purchased from GM The Software is for use exclusively with the Asra Osicus Audiometer In the event that the Licensee ceases to own or loan the audiometer or this license is terminated for any reason you agree to remove the Software from all computers and destroy all associated copies and documentation GM and its suppliers own all title and intellectual property rights in the Software GM is not liable for any consequential damages arising from the use of the Software such use being outside its control 29
14. en press the Produce Tone button As each tone is produced points will be plotted on the audiograms showing the progress of the test The audiogram will show the last response at each freguency If no response is recorded at 90 dBHL this will be recorded as no response on the audiogram 4 3 Audiograms and HSE Categories Audiograms are the recognised method of displaying hearing test data They are graphs showing the level at which the subject responded for each tone Each ear is graphed separately Right Ear Left Ear 10 0 10 20 30 40 60 70 80 a w N gt ND 2 8 90 gt 0 25 0 5 1 244 6 B 0 25 06 1 23 4 6 8 Frequency KHz Frequency kHz Fig 4 4 As the test proceeds points are plotted on the audiogram representing the test subject s results The above shows an example of audiograms for the left and right ears The left ear audiogram is blue and points are plotted using crosses The right ear audiogram is red with points plotted 22 using circles No response to a frequency is plotted at 90 dBHL maximum amplitude and the symbol includes an arrow pointing down This is shown above at 3 and 4 kHz onthe left ear Atthe end ofthe test press the button to calculate the HSE categories Depending on the circumstances caution is recommended in discussing audiogram results and HSE Categories with subjects User comments can be added by typing in the User Comments bo
15. icator fe 10 10 Gi 0 0 fel a 10 10 E a Tone Indicator 8 30 30 D E 40 40 5 50 60 60 70 70 90 90 0 25 0 5 1 23 4 6 6 0 25 0 5 1 2 WE 155 8 Frequency kHz Frequency kHz Details Test HSE Classification Name Sarah Stewart Automatic Manual Pulsed Tones Category F Gender Female b Additional ID Number 123 Notes Date Of Birth 08 February 1948 v Run lest Recall Date 01 April 2011 User Comments Classify Fig 4 1 To start a hearing test click on the Run Test button During the hearing test the subject will hear tones in one ear at each of up to eight different frequencies and then again in the other ear Each tone will increase in volume until the subject confirms that they have heard the tone by pressing the response switch The system will run through this several times for each tone to ensure a consistent response If there is no consistent response you will be notified by a message appearing on screen As the test proceeds the results will be plotted on the audiogram 21 If at any point the test must be paused or stopped use the buttons provided on the interface Pressing Pause will temporarily stop the test allowing it to be restarted atthe current freguency Pressing Stop will stop the test but retain all results up to that point 4 2 Manual Operation To switch to manual operation select the Manual Test tab as shown above To produce a tone select the freguency amplitude ear and th
16. is document or withdraw it at any time without prior notice Warranty This warranty is extended to the original purchaser of the audiometer by GM Instruments Ltd through approved Distributors or through GM Instruments Ltd and covers defects in materials of workmanship for a period of 1 year from the date of delivery to the original purchaser Defects will be corrected at no cost to the purchaser within the first year except for shipping charges to and from the point of service This warranty does not apply to those parts that are subject to normal wear and tear such as cords ear cushions and headbands Replaceable parts which may deteriorate with use will be supplied at a reasonable cost The manufacturers warranty is void if the audiometer is repaired by persons other than GM Instruments Ltd or an approved Distributor The terms of this warranty do not affect your statutory rights Asra Osicus Audiometer The Asra Osicus pure tone air conduction audiometer is manufactured by GM Instruments It is a screening device that is primarily designed for use in determining hearing threshold levels in comparison with standard reference threshold levels If properly operated maintained and calibrated the audiometer will allow the operator to screen subjects for changes in hearing acuity The audiometer is used to record the subject s current threshold levels Threshold levels may be affected from day to day by anumber of factors including noi
17. luence the final outcome However it is often found to be useful in reinforcing the message that hearing conservation matters The current audiogram can be superimposed on the predicted by clicking on the Compare with Current Test button To print a report of the predicted results press the Print button Details Tests Audiograms Predictive Analysis Right Ear Left Ear Legend 15 1 03 T 1 2 2 3 a 4 oa I 1 23 4 6 8 1 2 3 4 6 B Frequency KHz Frequency kHz o HSE Category i Hearing within normal limits Date of Last Test 15 01 22003 Compare ith C t Date of Predicted Test 15 01 2004 2 Ted Calculate Clear Predicted i Results Comparison Additional Notes Fig 3 4 20 4 Running Hearing Tests Having previously either entered details for a new person or selected someone who has been tested before click on Run Test from the home screen Before testing you should ensure that the subject s ears are not blocked the audiometer is connected and has been tested and the headphones are correctly in place 4 1 Automatic Operation To use automatic operation check that the Automatic Test tab is set as shown above and decide whether or not you want to have standard tone presentations or pulsed tone presentations If pulsed click on the Pulsed Tones tick box Hearing Test Right Ear Left Ear Response Ind
18. ment WEEE The Directive determines the framework for the return and recycling of used appliances as applicable throughout the European Union This label is applied to various products to indicate that the product is not to be thrown away but rather reclaimed atthe end ofits life as per this Directive Please contact GM Instruments at the address in this manual to arrange return of the device Your Asra Osicus audiometer is a medical device the design and production of which is covered by the European Medical Device Directive and monitored by Intertek Amtac our Notified Body under registration number 0473 0473 Audiometer Features Electrical characteristics Voltage 5V Freguency DC Current 100mA Performance and Accuracy Audiometer specifications are within the limits as stated in BS EN ISO 60645 Freguencies 250 500Hz 1 2 3 4 6 8KHz Accuracy 0 1 Harmonic Distortion 0 1 Hearing Level Range 10dB HL to 90dB HL Accuracy 0 5dB Linearity 0 2dB Standards Audiometry BS EN 60645 Electrical BS EN 60601 CE Marked as a Medical Device Size 122 x82 x 39 mm Weight 0 3 Kg Power 5V 100mA 0 5W Software The Asra Osicus software runs on Windows operating systems 2000 XP Vista or Windows 7 Ensure that the latest service packs have been installed and that NET and the Microsoft Installer are also up to date before installation The software is supplied on a CD along with the d
19. rivers required to run the USB interface WARNINGS To ensure patient safety only PC s and printers which comply with EN 60950 and which when used in combination with Asra Osicus do not exceed allowable patient leakage current should be used Live parts are made accessible when cover is removed Never remove covers unless gualified to do so In the event of damage to the circuit board there is the remote possibility that the audiometer may produce a tone at 130dBHL for more than 2 seconds This may damage the hearing of a person wearing the headphones if this occurred Disconnect audiometer and remove headphones as guickly as possible If hearing damage is suspected consult a doctor Please notify GM Instruments Each time you use the audiometer ensure all the parts are correctly connected to the sound module and the module is correctly connected to the computer which hasthe Asra Osicus software loaded onto it An audiometer is calibrated with one set of headphones The audiometer number and matching headphone numbers are stored during audiometer setup The audiometer should only be used with the headphones used during calibration Not performing the daily and weekly checks may invalidate any testing that you do as the audiometer may not have been working correctly Water or fluids should not be allowed to enter the case or the internal electronics may be damaged Do not apply pressure to the headphones themselves or this may
20. se exposure colds sinus infections or other problems Throughout this manual testing refers to the screening procedure used to establish thresholds hearing levels and is in no way attempting to diagnose monitor or treat any medical problem disease or injury Where a problem is suspected the subject should be referred to an audiologist or medical doctor for evaluation The audiograms obtained from this screening procedure provide a way for records to be maintained for the subject and for the company where the subject works in order that an audiologist or medical doctor may more fully evaluate and prevent major hearing problems To guarantee accuracy each audiometer must be calibrated at least once each year and receive an exhaustive calibration every two years Daily biological tests through the operator listening to each freguency and verifying the attenuator operation ensures accuracy and purity of the audiometer tones The software will run under Windows 2000 XP Vista or Windows 7 ona laptop or desktop PC Provided the specification of the PC is approved by Microsoft to run the version of Windows in use your Asra Osicus will run properly Note the warning message relating to PC safety on page 8 ofthis manual WEEE Notice This mark applies only to countries within the European Union EU and Norway This device is labelled in accordance with European Directive 2002 96 EC concerning waste electrical and electronic eguip
21. tact GM Instruments to have your audiometer calibrated Daily and weekly checks should also be carried out to ensure correct operation These can be performed using the Asra Osicus software Ensure the sockets on the sound module are free from dust This can be done by gently blowing air into the socket No other maintenance needs to be done on the sound module Storage The audiometer comes with a box and packaging that is designed for the safe storage of the sound module cables and headphones It is recommended that all cables the module and the headphones are returned to the packaging when not in use Keep the packaged audiometer in a dry dust free location 26 5 3 Appendix C Hearing Test Procedure The recommended hearing testing procedures are based on the British Standards BS 6655 1986 ISO 6189 1983 and BS EN ISO 8253 1 1998 Automatic operation of the software will perform tests following these standards When performing manual tests the following steps should be used as a guide Eguipment Check e Otoscope ensure that batteries have been inserted and bulb is working e Clean and examine the audiometer and all accessories Check earphone cushions plugs leads and accessory leads for signs of wear or damage e Switch on eguipment and leave for 5 minutes e Checkthat audiometer number and earphone numbers tally e Perform a daily check to ensure that the audiometer earphones and response switch are performing corr
22. the Home Screen The Home screen is the central point where the functions of the audiometer can be accessed Clicking on the Home icon at any time will return you to the Home screen From the Home screen you can create New records Find records Run Tests and Exit the program all by clicking on the associated icon Additionally you can prepare the audiometer for use by using the 4 setup buttons Perform machine Checks Select Audiometer Settings Tester Settings The following chapter takes you through these functions Osicus AELE HOME NEW FIND RUN TEST EXIT Perform Machine Perform daily and weekly checks on the audiometer equipment Checks Sel Taas Select audiometer for use and load calibration file View and update test settings Tester Settings Enter tester details Fig 2 2 11 2 3 Perform Machine Checks When you click on the start button the system presents a series of tones at whatever level you select in one ear followed by the other and logs your response to the tones This allows you to hear each freguency listening for distortion or a change in level If you click on Save the responses to the test tones will be saved to a file for record keeping purposes 9 Audiometer Check Response Indicator Hearing level dB HL 60 Fig 2 3 12 2 4 Select Audiometer Audiometer Audiometer Serial Number 09 008 Left Earphone Number LC466142 Right Earphone Number RC46
23. x These can relate to any observations during the test and will be printed on the audiograms The results must be saved to the database before exiting the test window Results can be saved by pressing the Save button The audiograms and related information can be printed as a report by pressing the Print button 4 4 Printing Audiograms When you choose to print audiograms a new window will open with a print preview of the report including any related personnel and test data From this window you can choose to print the document to a selected printer save the document to file or zoom in and out of the document 23 5 5 1 Appendix A HSE Categories The following tables A1 and A2 are used to perform HSE Categorisation on the audiogram produced from the hearing tests Sum of hearing levels 1 2 3 4 and 6 kHz Age Males Females Warning Referral Warning Referral Level Level Level Level 18 24 51 95 46 78 25 29 67 113 55 91 30 34 82 132 63 105 35 39 100 154 71 119 40 44 121 183 80 134 45 49 142 211 93 153 50 54 165 240 111 176 55 59 190 269 131 204 60 64 217 296 157 235 65 235 311 175 255 Table 5 1 1 Classification of hearing levels into warning and referral levels The warning and referral levels from table A1 above are compared with the sum of the results at 1kHz 2kHz 3kHz 4 kHz and 6kHz for each ear If the sum for both ears is below the warning level an HSE
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