Operating Instructions ST 20
Contents
1. MAICO Diagnostic GmbH MAICO Operating Instructions MAICO ST 20 MAICO Diagnostic GmbH Salzufer 13 14 D 10587 BERLIN Tel 49 30 70714650 Fax 49 30 70714699 Operating Instructions ST 20 M MAICO Table of Contents Page 1 IntroductlIon aaiaaaaaaaaaiaaaaaaaanaanaannannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnannnnannani 3 2 Description iiziiziaiaaiaiaaiaaaaanannannanannanaannannnnnnnannannnnnnnannnnnnannaannnnanaanaaii 4 3 Getting started aiiniiaaaaaaaaaaaaaaanaaanaanaanaaanaanananaanannnaannananannanaananinaanaani 6 4 1 Air Conduction AC test iaiiinaaaaaaaaaaaaanaaaasasaanasaaaasaaaasaasasaaaaaaadaaaa 8 4 1 1 Screening test iiiiiiaaiaaaaiaaaaaaaananaanaanannanaanannanaananaanaanaananaanaanaaa 8 4 1 2 Hearing Threshold Test iiiaaaaaaaaaaaaaaaaaaaaaanaanaaanaanaaanaanaandaanaan 9 4 1 3 Masking in the air conduction measurement iiiiiisaissssaani 10 4 2 Test of the Bone Conduction BC ST 20 BC and ST 20 SISI only 11 4 2 1 Hearing threshold test aaiiaiaaaaaaaaaanaannnanannannananannananaanaanaaanani 11 4 2 2 Masking in the bone conduction measurement ST 20 BC and ST 20 SJ FEET A I I TT TT 11 4 3 Tests in Free field FF with loudspeaker optional 12 4 3 1 Reflex and Direction Tests for free field measurements 12 4 4 How to run the SISI Test ST 20 SISI only uaaiiaaaaaaaaaaaaaaaaisasasassassd2. MAICO Internet www maico biz Geba_ST20_Fe_10a doc 27 851 307 1 04 10 Front panel with controls and displays D 2 G 4 6 6 7 D Power switch AC Q BC CP FF key lighting LED shows if AC BC or FF is selected Masking key LED lights when masking is on 7 R Pulse key LED lights when pulse is on B A a A SISI key LED lights when SISI test is selected SISI function only with ST 20 SISI Press more than 3 sec to toggle between Presentation or Interruption of the test tone e Taa re Right ear red LED lights when right red ear selected o o Audiogramme tonal _ Name om Non to access Setup menu press right ear key during b Adresse Address Direcci n power on only with optional LCD display or ST 20 SISI Pee Ga ek Left ear blue LED lights when left blue ear selected ohp a ee Signal interrupter presenter key mode change with SISI key a eE 0 ER Level slider E K co oo Signal presentation LED lights test signal on T oe A LED off test signal off SAR Es 7 Conduetonosseuse LED flashes test signal pulses EE eo HE Audiogram form iz Lightpoint shows actual level and frequency R i flashes when optional patient response switch is pressed 4 J O B Frequency down M o o Frequency up gt a 4 nr MMAICO ST 20 Rear panel with conne
3. Operating Instructions ST 20 M MAICO 5 Recommended literature Audiometric Interpretation A Manual of Basic Audiometry Lloyd Lyle L and Harriet Kaplan Baltimore University Park Press 1980 Auditory Disorders A Manual for Clinical Evaluation Jerger Susan and James Jerger Boston College Hill Press 1981 Handbook of Clinical Audiology Katz Jack Baltimore William amp Wilkins 1994 Roesers Audiology Desk Reference Roeser Ross J New York Stuttgart Thieme 1996 Auditory Diagnosis Silam Shlomo and Carol A Silvermann San Diego London Singular Publishing Group 1997 Geba_ST20 Fe _10a doc 15 851 307 1 04 10 Operating Instructions ST 20 M MAICO 6 Care and maintenance of the instrument Disconnect the mains plug before cleaning To clean the instrument headphones bone conduction receiver and loud speaker use a soft cloth dampened with a little warm soapy water or washing up liquid no alcohol or spirits should be used The headphone cushion and the ear cushions of the headphone Holmco 8103 can be detached for cleaning Please proceed as shown in picture 28 To remove the ear cushion first remove the rubber ring To assemble the cleaned or changed ear cushion start at the rounded location of the headphone During cleaning please ensure that no liquid runs into the switches level control headphone capsules or loudspeaker openings Picture 28 changing of the ear cushions of H
4. Vers Headphone AC left blue sleeve ground tip output Zo 80 U0 3 5 Vers Mains socket lett right mains 230 V 50 Hz MULTIFV PORT CTh Picture 30 rear of ST 20 with connection plugs Calibration values AC Receiver Holmberg 8103 B26 Force 13 16 N Reference equivalent threshold sound pressure level according to ISO 389 1 with Coupler according to IEC 303 Frequency Hz dB re 20 Pa sound damping dB Geba_ST20_Fe_10a doc 21 851 307 1 04 10 Operating Instructions ST 20 Calibration values BC Receiver Radioear B 71 Force 4 9 5 9 N Reference equivalent air radiation threshold force level HTLap HTLe according to ISO 389 3 minimum maximum Frequency HZ dB re 1 U Calibration values FF Loudspeaker Part No 801503 Reference sound pressure level Frequency HZ re 20 uP Geba_ST20 Fe 10a doc 22 851 307 1 04 10 M MAICO Standard accessories Optional accessories Consumables Geba_ST20_Fe_10a doc Operating Instructions ST 20 1 air conduction receiver Holmco 8103 B 26 1 pad of audiogram paper 50 sheets 1 mains cord 1 bone conduction receiver B 71 ST 20 BC ST 20 SISI only 1 patient response switch ST 20 SISI only 1 LCD display ST 20 SISI only Carrying case for the device and accessories Part No 705050 Loudspeaker Part No 801503 Headphone padding for children Part No 8698847632 Patient response switch Part No 80101249 LCD display tor
5. 1 Front panel of ST 20The bone conduction measurement with the ST 20 BC can be carried out with seven test frequencies trom 250 Hz to 6 kHz and a range of 10 dBHL up to 70 dBHL If requested the test signal can automatic be masked with the opposite headphone The optional loudspeaker delivers test levels trom 10dBHL to 90 dBHL for tree field measurement at a distance of 10 cm MAICO ST 20 M a Picture 1 Front panel of ST 20 Geba_ST20 Fe _10a doc 4 851 307 1 04 10 M Operating Instructions ST 20 MAICO In addition to the features found in the ST 20 BC the ST 20 SISI offers the SISl Test diagnostic function For this purpose the ST 20 SISI is equipped with a patient response switch and a LCD display which shows level and frequency or the SISI test information and the test score Picture 2 LCD Display The patient response switch is a standard accessory of the ST 20 SISI but is offered as an option on the other models Whenever the patient hears the test tone he presses the patient response switch The patient response is indicated by the flashing of the red light point The audiometric value can easily be marked on the audiogram paper Picture 3 Patient response switchWhen you push any key of the ST 20 a message Flashtext will be shown for a short time on the optional LCD Display i e Masking on This message gives information about the function or status of the key This feature makes it easy for in
6. 10 dBHL 100 dBHL for 250 Hz 6 kHz 8 kHz to 90 dB BC with bone conduction receiver B 71 only ST 20 BC SISI 10 dBHL 70 dBHL for 250 Hz 35 dB 6 kHz 40 dB 500 Hz 4 kHz 60 dB 3 kHz 65 dB FF with loudspeaker optional 10 dBSPL 90 dBSPL measurement 10 cm away from the ear Test Signal Pure tone or pulse tone Masking Signal broadband white noise Masking Level automatic AC 15 dB lower as the actual test level BC 15 dB higher as the actual test level Modulation pulse tone on off modulation time 0 5 s SISI test 5 dB 3 dB 2 dB conditioning 1 dB test Modulation time 4 8 0 2 s Interrupter Interruption or presentation of the test signal changeable via setup menu Power Supply 230V 50 Hz 10 Power Consumption 4VA Device Fuses 50 mA semi time lag internal Warm up time gt 10 min after power on Environment conditions 15 35 C operation 5 50 C storage Maximum humidity 90 storage and operation Dimensions WxHxD 29x22 x 6 cm Weight 1 9 kg Geba_ST20 Fe_10a doc 20 851 307 1 04 10 Operating Instructions ST 20 M MAICO Connectors Connection Specification serial PC Interface RS 232 C Patient response switchsleeve ground tip input RI 100 kQ Loudspeaker sleeve ground tip output Zo 80 Uo 3 5 VRMs Bone conductor BC sleeve ground tip output Zo 8Q0 Uo 3 5 Vans Headphone AC right red sleeve ground tio output Zo 80 U0 3 5
7. Choose with key or the poorer ear and repeat the hearing threshold test 4 1 3 Masking in the air conduction measurement In the air conduction threshold measurement the opposite ear must be masked if a larger difference between both ears appears The masking signal is a broad band noise which will be selected automatically 15 dB lower than the actual hearing level setting The masking signal is applied to the opposite ear through the air conduction headset Opposite ear describes the current not tested ear if the left ear is tested the right ear is the opposite ear This Picture 9 LCD display masking signal masks the test tone and prevents a Masking on detection of the test signal through the better ear Press key to enable the masking If your ST 20 has the optional LCD display for a short 7 time a corresponding message Is displayed see EE E RORA picture 9 Later the actual test level is displayed on the left and the masking level on the right of the LCD display Example picture Masking off 10 shows a test level of 50 dBHL and a Picture 11 LCD display masking level of 35 dBHL Masking ou To disable masking press key again If your ST 20 has the optional LCD display for a short time a corresponding message is displayed see picture 11 Attention When the channel R L is changed or the acoustic transducer AC or BC cp FF Kis changed the frequency is automatically set to the starting point of 1 kHz Thi
8. Geba_ST20 Fe _10a doc 12 851 307 1 04 10 Operating Instructions ST 20 M MAICO 4 4 How to run the SISI Test ST 20 SISI only The SISI Short Increment Sensitivity Index test provides a measurement in the supraliminal intensity area It offers additional information to the hearing thresholds measured in sections 4 1 2 and or 4 2 1 Thereby it is possible to distinguish between sensory inner ear and neural auditory nerve hearing damage The SlSl test is started by pressing the SISI key To train the patient to the SlSl test louder oe increments of 5 2 and 1 dB are presented to the arya patient before the test The test tone is increased by 1 dB for a period of 0 2 seconds every 4 8 qa seconds R L o a Whenever the patient hears the increment he she Picture 17 SISI_Display presses the patient response switch The SISl test Information and the test score are shown on the LCD display The test will end automatically after 20 presented increments 4 4 1 Preparation of the Test Set the test frequency with the frequency keys or For the test you should choose the frequency level where the maximum bone conduction hearing loss was measured see 4 2 Set the test level with the level control slider The volume is set to 20 dB above the individual hearing threshold measured under section 4 2 It must reach at least 60 dBspl The patient must be Instructed You will now hear a continuous tone E
9. am form as follows gt right and lt left 4 2 2 Masking in the bone conduction measurement ST 20 BC and ST 20 SISI In the bone conduction threshold measurement the opposite ear must be masked if a difference of at least 10 dBHL between both ears appears The masking signal is a broad band noise which will be selected automatically 15 dB higher than the actual hearing level setting The masking signal is applied to the opposite ear through the air conduction headset Opposite ear describes the current not tested ear if the left ear is tested the right ear Is the opposite ear This masking signal masks the test tone and prevents a detection of the test signal through the non tested ear Press key to enable the masking If your ST 20 has the optional LCD display for a short time a corresponding message is displayed see picture 13 vo S Later the actual test level is displayed on Geba_ST20 Fe_10a doc 11 851 307 1 04 10 Operating Instructions ST 20 M MAICO the left and the masking level on the right of the LCD display Example picture 14 shows a test level of 50 dBHL and a masking level of 65 dBHL To disable masking press key again If your ST 20 has the optional LCD display for a short time a corresponding message Is displayed see 50 1000 R HL 65 picture 1 gt Picture 14 LCD Display Continue as described before under 4 2 1 Test and masking level bone conduction test Put the headph
10. assassaan 13 4 4 1 Preparation of the Test aiiiaaaaaaaaaaaaaaaaaaasnaaaanaasnaaannansnaannaanan 13 4 4 2 Training of the Patlent 2aiaaaiaaaaasasaasasasasnnananaasnaaasaaasnaaannaaan 13 5 Recommended literature iiiiaaaaiaaaaaaaaasaaaaaaaaaaaaanaanaaanaanaaanaanaanaaanaanai 15 6 Care and maintenance of the Instrument 2 iiaaiiiaaaaananansnsannnaannaani 16 7 Trouble SNOOTING iiaiaaiaaaaaaiaaaaaaaaaaaaanaaanaanannaannaanannnnannnnaananinnanaandnanaanaai 17 8 Individual Setup of the ST 20 aiiiaiiaaaaaaaaaasaaasaaasaaaanaaasanasasanasnaasnaassaasaaan 18 9 Technical Data and ACCessory ianianiiaaaaaiaaaaaaaaaaaaanaaaaaaaaanaaaaaaaaanaaaaaanaai 20 10 Warranty Maintenance and After Sales Service siiaiiaasiaassaassaassani 24 11 Safety Regulations aiaiaaaiaaaaaaanaasaaanaannanannannnannnnannnannnnnnnnannnnnnnnannnni 25 11 1 Electrical Safety 2iiiaiiaaaaaaaaaaannnnaannannnannnnnnnnnnnnnnnnnnnnnnnnnnnnnnaninsannaani 25 Geba_ST20 Fe _10a doc 1 851 307 1 04 10 Operating Instructions ST 20 M MAICO 11 2 Measuring security iiiiiiaaaaaaaaanaanannnnnnnnnnnnnnnnnnnnnnnnnanninanaanaanasdanaanani 25 11 3 Device control aiinainniaaannnnnnnnnannnnnnnnnnnnnnnnnnnnnnnnnnannannnannanaansannasnani 25 11 4 Operation iiiiaiaaaaiaaaanaanaananaanaanannannanannannanaanaanannanaananaanaananaanaaaani 25 11 5 Patient Safety a
11. asses Ensure the headphones are put on correctly Red side on the right blue side on the left Adjust the headband of the headphones so picture 6 Headphone that the receivers are at the correct height the sound output grid exactly facing the ear channel Place the audiogram paper on the two holding pins Press the key until the according LED lt lights for AC Press the red key for the right ear or the blue key Tor the lett ear Controls and displays D Power switch AC BCCP FF d Masking Pulse SISI Right ear red Lett ear blue Signal interrupter key Level slide control Signal presentation 3 Audiogram form Light point B Frequency down k 3 lt Frequency up 4 Picture 7 Front panel of ST 20 with controls and displays Geba_ST20 Fe _10a doc 8 851 307 1 04 10 M MAICO Operating Instructions ST 20 Set the slider level control at 30 dB Test through the frequencies After switching on the frequency is automatically set to 1 kHz Start at 1 kHz set the higher frequencies first then the low frequencies Use the right key to select the higher frequencies and use the left key to select the lower frequencies Use the interrupter key to interrupt the test tone The green signal presentation LED should extinguish If the patient hears the test tone the particular value is displayed by a light point i
12. aste According to this all MAICO products sold after August 13 2005 are marked with a crossed out wheeled bin Within the limits of Article 9 of DIRECTIVE 2002 96 EC on waste electrical and electronic equipment WEEE MAICO has changed their sales policy To avoid additional distribution costs we assign the responsibility for the proper collection and treatment according legal regulations to our customers Geba_ST20_Fe_10a doc 24 851 307 1 04 10 M Operating Instructions ST 20 MAICO 11 Safety Regulations 11 1 Electrical Safety The ST 20 audiometer is constructed to comply with protection class Il of the international standard IEC 601 1 EN 60601 1 Protection from an electric shock Is ensured even without the system earth connection The instruments are not intended for operation In areas with an explosion hazard 11 2 Measuring security To guarantee that the audiometer works properly the instrument has to be checked and calibrated at least once a year The service and calibration must be performed by an authorized service center In accordance with the regulations of the EU medical directive we will drop our liability if these checks are not done The use of non calibrated audiometers is not allowed 11 3 Device control The user of the instrument should pertorm a subjective instrument check once a week This check can be done following the list for subjective instrument check see next page For your
13. babies children and adults It is a handy semi automatic audiometer that is easy to operate facilitates quick uncomplicated detection of hearing defects It has been designed for use in the office of the paediatrician and in general practice in the public health services and in occupational medicine As a result of modern microprocessor technology the ST 20 is very comfortable to use and has a high operating reliability A PC interface for data transfer to a connected computer is available special interface cord required The tests can be performed with a continuous or pulsed tone via headphones Masking with the opposite headphone is possible if needed In addition bone conduction measurement can be done with the ST 20 BC and ST 20 SISI Free field transmission is possible via the optional loudspeaker Moreover the ST 20 SISI offers the opportunity to conduct the SISl test The frequency and intensity level are set without any electronic static noises The test tone is adjusted by means of a slider control for the level in 5 dB steps and the frequency adjustments are made by electronic push buttons The particular value of frequency level is indicated by a red light point in the audiogram field In addition the optional LCD display picture 2 shows level and frequency standard accessory of ST 20 SISI The ST 20 offers eight test frequencies from 250 Hz up to 8 kHz and a range of 10 dBHL up to 100 dBHL for air conduction Picture
14. ctors Serial PC Interface or optional LCD Display Patient response switch Loudspeaker Bone conductor BC 9 1 12 3 Headphone AC right red Headphone AC left blue Mains socket 230 V 50 Hz PORT
15. d this part of the test also press the SISI key The modulation level will be reduced to 2 dB If the patient has understood the test up to here press the SISI key again to begin the SISI test The LCD display indicates SISI see picture 24 and the modulation level is adjusted to 1 dB Now 20 increments will be presented to the patient and the examiner can follow the test on the LCD display see example picture 25 The test will end automatically after 20 presented increments The number of detected increments is counted and indicated as a percentage see picture 26 The percent result and the test frequency are entered in the middle of the audiogram form If you are sure that the result of the test is stable you can interrupt the test at any time by pressing the pulse key The result is then indicated accordingly picture 27 Retrocochlear neural hearing damage is represented by results lt 25 a cochlear inner ear detect by values gt 70 Press the SISI key to leave the SISI test Geba_ST20 Fe _10a doc 14 5dB IO of 0 Picture 20 patient answer 5dB 1 of 1 Picture 21 valid answer 3dB 0 of O 2dB 0 of 0 V V N A at j C D D N N UJ N A N O O gt D gt a Q N w Q Q WO JJ SISI 0 of 0 Picture 24 start SISI Test SISI O 8M of 12 Picture 25 Example SISI Test 10 of 20 2000Hz Picture 26 result SISI test 100 of 9 2000Hz 851 307 1 04 10
16. e G for Noise V for signal distortion S for switching masking noise Right Ear evel kHz 0 250 5 1 2 B A 6 B 025 51 2 B A 6 8 kHz odde S A Bosih TS f ee S S poB f o f BOdBHL f ee pt posh When noise B G V or S is blocked inform the service center When the test tone Is heard at the masking ear contact the service center Air Conduction Audiogram pota r bevel pef Ear kHz 025051 2 B 4 b e SE e E EEE e _ Left Left Earpiec an Earpiec Right Right Earpiec ony Earpiec ox x axx Should is the last measurement of the patient For inverted measurement please reattach the headphone If the frequency difference between Should and Is for one ear averages more than 10 dB contact the SERVICE CENTER Bone Conduction Audiogram RightEar level leftEar LeftEar S S kHz 0 2505 2 B 14 6 sp p p e E E E et ty tt dee t O dBHV Pt tt dtd Bow fob Eb EEE dBHV If the frequency difference between Should and Is for one ear averages more than 10 dB contact the SERVICE CENTER Geba_ST20 Fe _10a doc 26 851 307 1 04 10 Operating Instructions ST 20 M MAICO Specifications are subject to change MAICO Diagnostic GmbH Salzufer 13 14 1058 Berlin Telefon 49 30 70 71 46 50 Telefax 49 30 70 71 46 99 e mail export maico biz
17. experienced users to get familiar with the ST 20 The audiometer is designed to be extremely service friendly Automatic test programs make D MAICO R L o gt O R aR Picture 2 LCD Display Picture 3 Patient response switch trouble shooting and the yearly check as easy as possible Geba_ST20 Fe _10a doc 5 851 307 1 04 10 Operating Instructions ST 20 M MAICO 3 Getting started The ST 20 should be operated in a quiet room so that the audiometric examinations are not influenced by outside noises However the sound insulation muffs of the headphones perform so well at excluding sound the instrument can be used in noisier environments Electro medical instruments which emit strong electromagnetic fields e g microwaves radiotherapy devices can influence the function of the audiometer Therefore the use of these instruments is not allowed in close proximity to the audiometer The test room must be at normal temperature usually 15 C to 35 C and the instrument should be switched on about 10 minutes before the first measurement to guarantee precise measuring results If the device has been cooled down e g during transport please wait until it has warmed up to room temperature Insert the instrument plug of the mains cord into the mains socket on the rear of the instrument Insert the other end of the mains cord into a 230 V shock proof socket Connect the right red headphone to
18. ianaiaaaaaaaaaaaaaaaaaaaaannaaannanannannnannnnnnnnnannnnnnnannnannnnannnnai 25 Geba_ST20_Fe_10a doc 2 851 307 1 04 10 M Operating Instructions ST 20 MAICO 1 Introduction Thank you very much for purchasing a quality product from the MAICO family This ST 20 audiometer is manufactured to meet all quality and safety requirements and has been certified with the CE symbol according to Medical Directive 93 42 EEC In designing the ST 20 we placed particular importance in making it a user friendly device meaning its operation Is simple and easy to understand And because ST 20 functions are software controlled upgrading later to new extended measurement functions will be simple and inexpensive That means that you have invested in a device that will adjust to your future needs This user manual should make It as easy as possible for you to become familiar with the functions of the ST 20 Please open out the flap of illustrations on the last page The description of the position e g of controls displays and connections found again in the text will make It easier for you to learn how to operate the ST 20 If you have problems or have ideas for further improvements please get in touch with us Simply call Your MAICO team Geba_ST20 Fe _10a doc 3 851 307 1 04 10 M Operating Instructions ST 20 MAICO 2 Description The audiometer ST 20 is a quick testing screening audiometer for audiometric tone examination of
19. level and frequency Part No 80 20 90 5 pads of audiogram paper 50 sheets Part No 861001 23 851 307 1 04 10 Operating Instructions ST 20 M MAICO 10 Warranty Maintenance and After Sales Service The MAICO ST 20 is guaranteed for 1 year This warranty is extended to the original purchaser of the instrument by MAICO through the distributor from whom it was purchased and covers defects in material and workmanship for a period of one year from date of delivery of the instrument to the original purchaser The ST 20 may be repaired and serviced only by your dealer or by a service center recommended by your dealer We urgently advise you against attempting to rectify any faults yourself or commissioning non experts to do SO In the event of repair during the guarantee period please enclose evidence of purchase with the instrument In order to ensure that your instrument works properly the ST 20 should be checked and calibrated at least once a year This check has to be carried out by your dealer When returning the instrument for repairs it is essential to send the headphones as well Send the device to your dealer or to a service center authorized by your dealer Please include a detailed description of faults In order to prevent damage in transit please use the original packing if possible when returning the instrument Within the European Union it is illegal to dispose electric and electronic waste as unsorted municipal w
20. n the audiogram field and should be marked on the audiogram paper The correct markings are O red right and X blue left If all tones are heard it can be assumed that the hearing loss if any is only minimal For hygienic reasons it is important to clean the ear cushions of the headphone see chapter 6 4 1 2 Hearing Threshold Test In the hearing threshold test the hearing threshold of the patient is measured in comparison with the normal hearing threshold for air conduction The test is Started on the ear with better hearing Set the slider level control to 10 dB Using the key or choose the ear that hears better Use the key to set the test frequency at 1 kHz For further preparation see 4 1 1 screening test Instruction to the person being tested Whenever the test tone is just audible the patient should raise their hand or press the patient response switch Increase the test level with Picture 8 Controls of ST 20 the slider level control gradually until the Geba_ST20 Fe _10a doc 9 851 307 1 04 10 Operating Instructions ST 20 M MAICO patient indicates that he she can just hear the test tone Press the interrupter key and mark the light point on the audiogram form Set the slider level control back to 10 dB select the next frequency increase the level again Test through the other frequencies in the same way
21. olmco 8103 Geba_ST20 Fe _10a doc 16 851 307 1 04 10 Operating Instructions ST 20 M MAICO 7 Trouble shooting If you should find that your instrument is no longer working properly during a test run please check the following points The acoustic transducers cannot be selected Level control must be set at 10 dB and the required key pressed Diodes do not light up and there is no light point on the audiogram field 0 Is the mains lead plugged in correctly Is the power switch at the On position Light point available but test tone is absent Green signal presentation LED does not light Level control must be set at 10 dB position Press signal interrupter key When the LED lights up and the tone is available the device works in presenter mode For switching over to interrupter operation press the SISI key longer than 3 seconds Are the acoustic transducers connected to the correct socket Is key In the right position Is the lead connecting the headphones or the loudspeaker loose or detective If your instrument still does not work properly after this short check please consult your dealer or send the instrument to your dealer or our service centre see also chapter 10 Geba_ST20 Fe _10a doc 17 851 307 1 04 10 Operating Instructions ST 20 8 Individual Setup of the ST 20 Only with optional LCD Display or ST 20 SISI possible The ST 20 is config
22. one with the according side on the opposite ear with the other side on the Masking off cheek bone in front of the test ear Adjust the Picture 15 LCD Display headband so that the headphone sits at the Masking off right height to the opposite ear the sound grid exactly facing the auditory passage see chapter 4 11 The marking for bone conduction with masking should be done with the symbols on the right and on the left in the audiogram form For hygienic reasons it is important to clean the bone conduction receiver see chapter 6 4 3 Tests in Free field FF with loudspeaker optional 4 3 1 Reflex and Direction Tests for free field measurements The test with babies and infants is performed with pulsed tones Set the level control at 10 dB Select FF by pressing key until the lamp under the symbol lights Press the pulse key The sound Is switched on and off periodically The green signal presentation LED flashes When it lights up the test tone can be heard Position the loudspeaker about 10 cm away from the ear to be tested Present the test tone by pressing the switch at the rear of the loudspeaker Increase the level control slowly When the child shows a reaction e g turns the head enter the measurement on the audiogram form with the remark loudspeaker testing Use the frequency keys A to select higher or lower frequencies Picture 16 Loudspeaker
23. own security you should copy the enclosed list fill it in once a week and store it in your Tiles 11 4 Operation Only skilled personnel Audiologists ENT professionals or other with equivalent knowledge should operate the instrument 11 5 Patient Safety Please note that if connection is made to standard equipment like printers and network special precautions must be taken In order to maintain medical safety Connecting this device to other devices in order to make a system may cause the safety specifications to be invalid It is therefore recommended to insert a galvanic separation between the device and the host computer unless the computer is battery operated or supplied by a medical approved power supply Galvanic separation must fulfil the EN 60 601 1 Geba_ST20 Fe _10a doc 25 851 307 1 04 10 Operating Instructions ST 20 M MAICO Checklist for Subjective Audiometer Testing Clean the ear and head cushion Untangle all lines when necessary Instrument Are the headphone cushion in good condition Man uta cturer If not gt replace Are plugs and leads in good condition undamaged Serial No Are all controls working properly Is the Patient Response Key working properly if available Exam INET Check batteries and renew if necessary Test Signal Quality All the test frequencies in the below table indicate typical hearing level and can be changed when necessary Masking B for Buzz ton
24. s function can be turned off in the setup menu see chapter 8 If the acoustic transducers or the channel R L cannot be selected set the level control to 10 dB If the maximum permitted level for the headphones bone conduction receiver or loudspeaker is exceeded the test signal will not increase The corresponding light point in the audiogram form flashes to indicate that the level limit has been reached Geba_ST20 Fe _10a doc 10 851 307 1 04 10 Operating Instructions ST 20 M MAICO 4 2 Test of the Bone Conduction BC ST 20 BC and ST 20 SISI only 4 2 1 Hearing threshold test In the hearing threshold test the hearing threshold of the patient is measured in comparison with the normal hearing threshold for bone conduction Differences in the measured hearing threshold for air conduction see 4 1 2 give indications of problems in the middle ear Picture 12 Bone conductor Set the slider level control to 10 dB Place the bone conduction receiver so that the flat circular side of the transducer Y is placed on the mastoid at the noticeable ledge of the cranial bone behind the auricle The other side of the headband is placed in front of the opposite ear Select BC by pressing key until the lamp under the CP symbol lights Perform the test the same way as for air conduction see 4 1 2 Enter the measurements for all frequencies on the form connect all points with dotted lines marked on the audiogr
25. shtext Time L Flashtext Time S Frequence Roll 0 Frequence Roll 1 TransducerchangeO Transducerchanget Language select Geba_ST20 Fe _10a doc Operating Instructions ST 20 The Flashtext time Function description of a pressed key on the LCD Display is long app 3 seconds Setting for inexperienced users The Flashtext time Function description of a pressed key on the LCD Display is short app 1 seconds Setting for experienced users Pressing the frequency key or at the lowest 250 Hz or highest 8 kHz resets the frequency to 1 kHz Pressing the frequency key or at the lowest 250 Hz or highest 8 kHz frequency rolls the frequency over to the highest 8 kHz or lowest 250 Hz frequency Changing between AC BC or FF with key keeps the actual test frequency unchanged Changing between AC BC or FF with key resets the test frequency to 1 kHz Choose your language for the text on the LCD Display Possible selections are English French Spanish and German 19 851 307 1 04 10 Operating Instructions ST 20 M MAICO 9 Technical Data and Accessory The ST 20 audiometer is an active diagnostic medical product according to the class lla of the EU medical directive 93 42 EEC Audiometer Class A 4 according to EN 60 645 1 Test Frequency 250 Hz 500 Hz 1 kHz 2 kHz 3 kHz 4 kHz 6 kHz 8 kHz Sound Pressure Level 5 dB level steps AC with earphone Holmco type 8103 B 26
26. sure The protective device is triggered by sound levels more than 50 dBHL and fades out the test sound This is indicated by the flashing of the light points in the audiogram form and green signal presentation LED gt In this case set the level control to the upper position and when the light point stops flashing the green signal presentation LED lights up and the test sound is faded in If during the initialization of the device the 250 Hz and 500 Hz light points start to flash the device has detected an error In this case contact customer service see chapter 10 Calibration of the device The instrument headphones bone conduction receiver ST 20 BC and ST 20 SISI only as well as the optional loudspeaker match one another and have the same serial number e g 6631520 It is not allowed to use the device with other transducers If one of the acoustic transducers is replaced the instrument must be recalibrated The use of non calibrated audiometers leads to incorrect measurements Geba_ST20 Fe _10a doc 7 851 307 1 04 10 Operating Instructions ST 20 M MAICO 4 Test procedure 4 1 Air Conduction AC test 4 1 1 Screening test The patient should sit at a distance of at least 1 m from the device Before putting on the headphones set the slider level control at 10 dB Eliminate any obstructions which will interfere with the placement of the earphone cushions on the ear i e hair eyegl
27. the correspondingly labelled socket and the left Blue headphone socket at the rear of the device If your device is equipped with a patient response switch plug it to socket The LCD display is connected to socket and screwed into the ST 20 The bone conduction receiver Cbot ST 20 BC and ST 20 SISI is connected to socket The optional loudspeaker is connected to socket 1 th O MULTI PORT Picture 4 rear panel of ST 20 with connectors Geba_ST20 Fe _10a doc 6 851 307 1 04 10 Operating Instructions ST 20 M MAICO Slide the level control completely to the top and turn on the device with switch The device starts its initial test automatically During this test all the light points LEDs in the audiogram form light up After the test the 1 kHz light point in the audiogram form and the green signal presentation LED J light up only in interrupter mode It in dicates that the test tone can be heard If the green signal presentation LED J does not light up and the 1 kHz light point flashes the level control needs to be set at 10 GB Due to the built in protective device the test signal has been faded out automatically psa es Te Patient safety The built in protective device makes sure that during the initialization or when changing the channel as well as from air conduction to bone conduction or free field the patient s ear is protected from high sound expo
28. ured to meet most requirements But it is also possible to setup some functions of the ST 20 to your individual needs These changes will be stored in the ST 20 even after you switch it off until you change it again in the setup To get into the setup menu of the ST 20 press the red key and switch on the instrument with the power switch Keep the red key pressed until you see on the LCD Display the text ST 20 After releasing the red key the message User menu and then the text shown in picture 29 Continuous Pulse appears on the LCD Display Picture 29 Setup You can toggle between the different items of Continuous pulse the setup menu using the frequency keys and S Select a particular item by pressing the signal interrupter key You see the actual setting flashing on the left of the LCD Display Change the actual setting with the frequency keys and Save the new setting with the signal interrupter key Toggle through further items of the setup menu with the frequency keys and Leave the setup menu by pressing the pulse key The setup menu of the ST 20 offers the following choices Continuous Pulcet The test signal is a steady tone ContinuousPulse1 The test signal is a pulse tone Pressing the signal key interrupts the test Inter Present signal Inter Present P Pressing the signal key presents the test signal Geba_ST20 Fe _10a doc 18 851 307 1 04 10 Fla
29. very time it becomes louder immediately push the key 4 4 2 Training of the Patient Only with careful training during the following conditioning phase can a valid test result can be SISI Conditioning achieved Picture 18 start display The SISI test is started by pressing the SISI key The LCD display indicates for approx two 5dB LIS O of O seconds the text shown in picture 18 ar Then the following text Is shown on the LCD display see picture 19 The left figure Indicates the current modulation level Geba_ST20 Fe _10a doc 13 851 307 1 04 10 M MAICO Operating Instructions ST 20 Initially the value is 5 dB That means the patient is presented with a continuous tone which is briefly increased every 4 8 seconds e g 60 dBHL to 65 dBHL This effect is shown on the LCD display by a note The white small box appears for approx 1 5 seconds During this period the patient may resoond If he she answers too early or too late the answer will not be accepted by the ST 20 When the patient presses the response switch the examiner will see a black box on the display see picture 20 The number of detected increments is counted and shown on the display Furthermore the number of presented increments is shown s picture 21 When you are sure that the patient has understood the object of the test press the SISI key again The modulation level will be reduced to 3 dB If the patient has understoo
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