MAICO MA 25 / MA 25e: Instruction for Use
This document provides instructions for the MAICO MA 25 and MA 25e screening audiometers.
1 Introduction
Thank you for selecting a MAICO product. The MA 25 is designed and manufactured to meet quality and safety requirements, certified with the CE-symbol according to the Medical Directive. Its user-friendly design makes operation simple and easy to learn. Software-controlled functions allow for future upgrades. This manual aims to facilitate learning and understanding of the MAICO MA 25 functions. For any problems or suggestions, please contact MAICO.
2 Description
2.1 Intended Use
The MA 25 / MA 25e screening audiometer is designed for screening hearing loss. Its output and specificity depend on user-defined characteristics and environmental conditions. A "normal hearing" result does not preclude other contraindications, and a full audiologic evaluation is recommended if hearing sensitivity concerns persist. The audiometer is intended for use by audiologists, hearing healthcare professionals, or trained technicians in a quiet environment.
Extended Functions (MA 25e):
The MA 25e includes two additional features:
- Hughson Westlake patient-controlled automatic threshold test (complying with ISO 8253), with results recallable from internal memory.
- Talk Forward function, useful in sound booth installations.
2.2 Important Safety Note
Operate the MA 25 in a quiet room with minimal magnetic influence to avoid disturbing external noise. Avoid operating electro-medical instruments emitting strong electromagnetic fields (e.g., microwaves, radiotherapy devices) near the MA 25. The examination room temperature should be between 15°C/59°F and 35°C/95°F. Allow the instrument to warm up to room temperature if it has cooled during transportation. The MAICO MA 25 is specified according to EN 60 601-1.
Attention: PLEASE READ THE ENTIRE MANUAL CAREFULLY BEFORE OPERATING THIS INSTRUMENT. Use only as described. Familiarize yourself with the instrument before use. Do not attempt to fix defects or damages yourself.
The audiometer and headphone share a serial number; use only the original headphone. Recalibration is required if a headphone is replaced. Uncalibrated instruments can lead to faulty measurements and hearing damage. Ensure all accessories are properly connected. To prevent cross-contamination, parts in direct contact with the patient (e.g., earphone cushions) must be disinfected after each use.
2.3 Unpacking and Checking the MA 25
Inspect the shipping box for damage or tampering. Notify the carrier immediately if damage is found. If the content box is damaged, check the instrument for electrical or mechanical defects and contact the dealer. Keep all original packaging for insurance claims and future use, such as sending the instrument for check-ups.
2.4 Accessories
- MA 25: Audiometer, Audiometric Headset, 1 Pad with 50 audiogram charts, Operating Instructions, 3 batteries.
- MA 25e: Same as MA 25, plus Patient response switch, Test Hughson-Westlake.
- Optional: Carrying bag.
2.5 Connecting the Accessories
All connection jacks are on the rear of the MA 25. Connect all cables and accessories before switching on the instrument.
Figure 1: Rear and bottom of the MA 25
The rear panel features connection ports:
- Position 1 (Battery): Compartment for three AA/LR6 batteries.
- Position 2 (Power / USB): Socket for external power supply or USB connection.
- Position 3 (Patient Resp.): Socket for patient response switch.
- Position 4 (Right): Socket for right headphone.
- Position 5 (Left): Socket for left headphone.
3 Function of buttons and display
The MA 25 features a digital display, knobs for 'Hearing Level' (dB) and 'Frequency' (Hz), and a 'Tone Switch' button. Four function buttons (F1-F4) are also present.
Power On and Power Off:
Power on requires headphones to be plugged in. Press the 'Tone Switch' button to turn on. Press the level and frequency dials simultaneously for a few seconds to turn off. The audiometer may also auto-power off after a set time (3, 4, or 5 minutes).
Pure Tone Presentation:
- Frequency: Use the 'Frequency Hz' dialer to select a frequency.
- Level: Use the 'Hearing Level dB' dialer to adjust the sound level.
- Present tone: Touch the 'Tone Switch'.
3.1 Function Buttons
- F1: MA 25 - Selects the Right ear. MA 25e - Toggles between Right and Left ears.
- F2: MA 25 - Selects the Left ear. MA 25e - Stores the threshold.
- F3 (Pulse / Pulse Off): Manual tone presentation. 'Pulse On' presents a pulsing tone.
- F4 (Warble / Warble off): 'Warble off' presents pure tones. 'Warble on' presents warble tones.
3.2 Special functions of MA 25e
- Talk Forward: Activated by holding the 'Hearing Level dB' dialer. The talk forward level can be adjusted while holding the 'Tone Switch'.
- Hughson-Westlake (HW): Accessed by pressing the frequency dialer. Functionalities include:
- F1: Delete all stored thresholds.
- F2: Store a 'Not Heard' threshold point.
- F3: Display stored L/R thresholds.
- F4: Start the HW automatic test procedure. Refer to Setup Menu for details.
3.3 Display
The display indicates:
- Tone: A tone presentation indicator in the top left corner (showing frequency, level, and pulse/warble status).
- Response: Patient response indicated in the middle of the display header.
- Power On or Battery status: Indicated in the top right corner. Icons change based on power source (external or battery). A 'Low Battery' warning will flash when battery power is low.
Power Off settings can be adjusted in the Setup section.
4 Performing Tone Audiometric Tests
Hearing threshold levels are determined by presenting test signals via earphones (air conduction - AC). AC audiometry establishes hearing sensitivity at various frequencies and can specify AC loss but not distinguish between conductive and sensor neural mechanisms.
Patient Setup:
- The patient should sit at least 1 meter from the device.
- Ensure no obstructions interfere with earphone placement (e.g., hair, eyeglasses).
- Position headphones correctly: Red side on the right, blue side on the left. Adjust the headband so earphones are at the correct height, aligning the sound output grid with the ear canal.
Instructions to Patient:
"You will now hear a variety of pitches with various loudness levels. Please push the response switch when you hear a tone and release the button when you no longer hear it." If not using the response switch, instruct the patient to "raise their left or right hand when you hear the tone in the left or right ear".
Threshold Determination:
The test typically starts at 1000 Hz on the patient's better ear. Background noise can affect results, especially at lower frequencies. Clean headphone ear cushions after testing for hygiene.
4.1 Performing Automatic Tone Audiometric Test (MA 25e)
The Hughson Westlake (HW) automatic test procedure (10 down, 5 up method) can be used. Prepare and instruct the patient as described above. Press the 'Frequency Hz' dialer and 'F4' to start the HW test. If Familiarization is active, the test begins at 1000 Hz with 40 dB and proceeds in 10 dB steps. Confirmed hearing levels are stored, and the next frequency is automatically selected, decreasing by 10 dB.
5 Setup Menu
To access the setup menu, press F1 and F4 simultaneously for 2-3 seconds.
- F1: Change setting.
- F2: Browse up in the menu.
- F3: Browse down in the menu.
- F4: Save settings and return to the previous screen.
Setup Options:
- Power Up Tone: Toggle between 'Manual' (tone presented as long as Tone Switch is active) and 'Reverse' (tone interrupted if Tone Switch is active).
- Power Up Ear: Select Right or Left ear as the default for power up.
- Default Intensity: Sets the default intensity when changing ear side (default 20 dB). Options range from Off to 50 dB in 5 dB steps.
- Intensity Steps: Choose between 1 dB and 5 dB steps.
- Power Off Settings: Configure 'Power Off' time for battery mode (Never, 1-5 minutes). With USB power, the device does not turn off.
- Pulse Length: Toggle between 250 msec and 500 msec.
- Language: Select between English, German, Spanish, and French.
- LCD Contrast: Adjust contrast from 0 (brightest) to 6 (darkest).
- HW Test (MA 25e): Configure Hughson Westlake test parameters:
- HW Familiarization: On/Off.
- HW Condition: "2 correct out of 3 answers" or "3 correct out of 5 answers".
- HW Frequencies: Select frequencies (125 Hz to 8 kHz) to include in the HW test by toggling On/Off.
- License: Access and modify the license key.
- About: View information about the device.
6 Warranty and Disclaimer
The MA 25 audiometer is guaranteed for 2 years from the date of delivery to the original purchaser, covering defects in material and workmanship. Repairs must be performed by a MAICO dealer or an authorized service center. Do not attempt self-repair. For warranty repairs, include proof of purchase. Annual inspection and calibration by a dealer are recommended for proper instrument function. When returning for repair, send the instrument, headphone, and accessories with a detailed description of faults. Use original packaging for transit to prevent damage.
7 Care and Maintenance
Disconnect the power plug before cleaning. Clean the instrument surface with a soft cloth moistened with a mild water and dishwashing detergent solution. Avoid organic solvents and aromatic oils. Ensure no contamination on parts contacting the patient after each examination. If ear cushions are contaminated, remove them before cleaning. Use water for frequent cleaning; use disinfectant for severe contamination. Always disconnect the mains conductor during cleaning and prevent fluid entry. Do not use alcohol or spirits.
8 Disinfection
Parts in direct contact with the patient (earphone cushions, response switch) should undergo standard disinfection procedures between patients. This includes physical cleaning and use of a recognized disinfectant, following the manufacturer's instructions. If ear cushions are contaminated, remove them before cleaning.
9 Safety Regulations
8.1 Electrical Safety
The MA 25 / MA 25e complies with Class B of EN 60601-1. Do not use in environments with explosive materials or equipment.
8.2 Measurement Safety
For safety and quality, an annual inspection and calibration by an authorized MAICO service center are required. MAICO is not liable for failures due to non-compliance with inspection dates. Use of uncalibrated and uninspected audiometers is prohibited.
8.3 Instrument Handling
The instrument should be checked once a week.
8.4 Operation
The instrument should only be handled and operated by trained personnel (audiologists, ENT doctors, or similarly qualified individuals).
10 Technical Data
| Standards | |
|---|---|
| Audiometer | EN 60645-1/ANSI S3.6, Type 4 |
| Safety | EN 60601-1 |
| EMC | EN 60601-1-2 |
Frequencies and Maximum Intensities:
| Frequency | 125 Hz | 250 Hz | 500 Hz | 750 Hz | 1 KHz | 1.5 KHz | 2 KHz | 3 KHz | 4 KHz | 6 KHz | 8 KHz |
|---|---|---|---|---|---|---|---|---|---|---|---|
| DD45 | 70 | 90 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 90 |
| DD65 | 65 | 75 | 90 | 95 | 95 | 95 | 95 | 95 | 95 | 90 | 85 |
Inputs: Patient response switch, USB-Power-Supply
Outputs: Left AC, Right AC
Attenuator: -10 to 100 dB HL in 5 dB steps.
Tone Presentation: Manual or reverse (chosen in Setup Menu); Multiple pulses 250 or 500 msec (chosen in Setup Menu); On/Off; pure tone or warble tone.
Talk Forward (MA 25e): Built-in talk forward microphone, 0-100 dBSPL adjustable.
Auto Threshold (MA 25e): Patient controlled Hughson Westlake procedure according to ISO 8253-1.
Store Function (MA 25e): Soft key (F2-key) store button and internal memory for AC L/R. Stored measurements can be viewed on the built-in display.
Modulation: Warble +/- 5% 5 Hz.
Calibration
Air Conduction: ISO 389-1/ANSI S3.6 (DD45).
Calibration values: AC-Headphone DD45 (Force 4-5 N)
| Frequency [Hz] | Reference equivalent threshold according to ISO 389-1 with coupler IEC 60 318-3 [dB] (re 20 μ Pa) |
|---|---|
| 125 | 47.5 |
| 250 | 27.0 |
| 500 | 13.0 |
| 750 | 6.5 |
| 1000 | 6.0 |
| 1500 | 8.0 |
| 2000 | 8.0 |
| 3000 | 8.0 |
| 4000 | 9.0 |
| 6000 | 20.5 |
| 8000 | 12.0 |
Calibration Values: AC Headphone Radioear DD65 (Force 10.1... 11.1 N)
| Frequency [Hz] | Reference equivalent threshold sound pressure level according to WDH-Standard with coupler IEC 60318-3 [dB] (re 20 μ Pa), |
|---|---|
| 125 | 52.5 |
| 250 | 39.5 |
| 500 | 19.5 |
| 750 | 11.0 |
| 1000 | 8.5 |
| 1500 | 13.0 |
| 2000 | 9.0 |
| 3000 | 11.5 |
| 4000 | 10.5 |
| 5000 | 14.5 |
| 6000 | 29.0 |
| 8000 | 14.0 |
Calibration values: AC Headphone Holmco 8103 B 26 (Force 13...16 N)
| Frequency [Hz] | Equivalent Reference Level according to ISO 389 - 2 Measured with Coupler IEC 60 318-3 [dB] (re 20 μPa) | Threshold Sound Masking [dB] |
|---|---|---|
| 125 | 39.5 | 12.5 |
| 250 | 25 | 14.5 |
| 500 | 18.5 | 18.5 |
| 750 | 13.5 | - |
| 1000 | 12.0 | 25 |
| 1500 | 10.0 | - |
| 2000 | 9.5 | 36.5 |
| 3000 | 9.0 | - |
| 4000 | 9.0 | 44 |
| 6000 | 19.5 | - |
| 8000 | 20.0 | 35 |
Calibration values: AC-Headphone TDH39 (Force 4-5 N)
| Frequency [Hz] | Reference equivalent threshold according to ISO 389-1 with coupler IEC 60 318-3 [dB] (re 20 μ Pa) |
|---|---|
| 125 | 45 |
| 250 | 25.5 |
| 500 | 11.5 |
| 750 | 7.5 |
| 1000 | 7 |
| 1500 | 6.5 |
| 2000 | 9 |
| 3000 | 10 |
| 4000 | 9.5 |
| 6000 | 15.5 |
| 8000 | 13 |
Dimensions and Specifications
Dimensions: W x D x H: 22.5 x 18 x 5.5 cm / 8.9 x 7.1 x 2.2 inches
Weight: 1.0 kg / 2.2 lbs (including batteries and headset); 1.6 kg / 3.5 lbs (including carrying bag, headset, audiogram charts etc.)
Power: 3 type AA batteries / External Power supply. Automatic battery on/off switching and status indication.
External Power Supply: 5V DC 100 - 240 V AC, 50 – 60 Hz. USB-Connector: 5VDC minimum 150 mA. Power supply must meet EN 60601-1.
Battery life: Standby: 6 months; Tone presentations: 70,000.
Construction: Plastic cabinet.
Additional parts: Response switch (Part No. 8011091), Carrying case (Part No. 8100796), Medical Power supply (Part No. 8006061).
Audiometer Testing Checklist
Checklist for Subjective Audiometer Testing:
- Clean the ear and head cushion.
- Untangle all lines when necessary.
- Check headphone cushions for good condition; replace if necessary.
- Check plugs and leads for good condition/undamaged.
- Verify all controls are working properly.
- Check if the Patient Response Key is working properly (if available).
- Check batteries and renew if necessary.
Instrument Details:
Instrument: ________________________ Manufacturer: ________________________ Serial No.: _________________________ Examiner: _________________________
Quality of test signals:
The table below lists typical hearing levels for test frequencies. Abbreviations can be used: "B" for Buzz tone, "G" for Noise, "V" for signal distortion, "S" for switching masking noise.
| Right Ear | Left Ear | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.25 | 0.5 | 1 | 2 | 3 | 4 | 6 | 8 kHz | 0.25 | 0.5 | 1 | 2 | 3 | 4 | 6 | 8 kHz | |
| AC 30dB HL | ||||||||||||||||
| AC 50dB HL | ||||||||||||||||
| AC 70dB HL | ||||||||||||||||
* When noise "B", "G", "V" or "S" has been checked, please inform your service center!
* If conduction test signals are also audible in the non-test ear, please inform your service center!
Air Conduction Audiogram with test person:
| Right Ear | Left Ear | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| kHz | 0.25 | 0.5 | 1 | 2 | 3 | 4 | 6 | 8 | 0.25 | 0.5 | 1 | 2 | 3 | 4 | 6 | 8 |
| Target dBHL* | ||||||||||||||||
| Left Earpiece | ||||||||||||||||
| Right Earpiece | ||||||||||||||||
| Actual dBHL** | ||||||||||||||||
| Left Earpiece | ||||||||||||||||
| Right Earpiece | ||||||||||||||||
* Target value is the value measured in the last audiogram of the test person.
** Repeat the measurement with headphones the wrong way around.
If the difference between target and actual value at a particular frequency or between right and left headphones is more than 10 dB, please inform your service center!
Tested: _________________________ Date: _________________________
Contact Information
Specifications are subject to change.
MAICO Diagnostics GmbH
Sickingenstr. 70-71
10553 Berlin
Germany
Tel.: +49 30 / 70 71 46-50
Fax: +49 30 / 70 71 46-99
E-mail: sales@maico.biz
Internet: www.maico.biz
