Welch Allyn GSI TM262 User manual

2.6 INITIAL SETUP

Place the TM 262TM Auto TympTM on a stable counter or table where it will subsequently be used, and near a properly grounded wall outlet. Attach accessories to their appropriately-labled connectors on the rear panel of the TM 262 (see Figure 2-9).

Locate the POWER switch on the rear panel of the TM 262 and move the switch to the ON ( ) position. Note that the lamp (F1) on the front panel is illuminated, indicating the TM 262 is receiving power. The TM 262 symbol will then appear on the display along with a listing of the revision number for the Tymp/Reflex and Audiometry (if purchased) software. Next, the display will default to the Tymp/Reflex mode and the probe’s green lamp will begin to blink, indicating that the TM 262 is ready to begin a test. If both the green and yellow lamps are illuminated at the same time, either the probe is occluded or the tymp/ reflex software did not properly initialize. Simply move the power switch to the OFF () position, inspect the probe tip for any signs of an occlusion, and reposition the power switch to ON ( ). If both green and yellow lamps are still illuminated and you are certain that the probe is not occluded, contact the Welch Allyn Technical Service Department (see page 55). In the meantime, it is still possible to select the Audiometry mode (if purchased).

Allow the instrument to warm-up for about five minutes before conducting a test. This allows the electronic circuits to stabilize prior to use.

If the storage temperature is lower than the room temperature, allow some additional time for the instrument to reach room temperature.

Warning

The TM 262 is designed to be used with a hospital grade outlet. Injury to personnel or damage to equipment can result when a three-prong to two-prong adapter is connected between the TM 262 power plug and an AC outlet or extension cord. Additionally, those TM 262 Auto Tymps that are equipped with power transformers use a specific transformer (8000-0260, 8000-0261 or 80000262) which should not be interchanged with any other transformer or supply. The TM 262 is a specifically-calibrated device and the periodic service and adjustments which the instrument may require should be done only by an authorized Welch Allyn service technician.

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2.6.1 Loading The Paper

Remove the printer cover (see Fig. 2-3 for location) by placing your fingers along the back edge of the printer and pulling upward on the cover. Cut the printer paper so that the leading edge of paper is straight across. Place the roll of paper inside the paper well so that the paper will unroll from the lower surface. See paper loading label for additional help (Figure 2-11).

Paper loading label

								YINTO
								SQUAREL	THE
					EDGE
								PRESSINGANEL
		LOADINGLEADING				WHILEFRONT
PAPER							THE
		THE		ENTRANCE
					ON
INSERT
THE	PAPER
			ADVANCE
PAPER

Paper exit

Paper entrance

FIGURE 2-11: Paper Loading

Position the leading edge of the paper roll into the paper entrance while pressing the PAPER ADVANCE button. The paper will begin to appear out of the printer mechanism. Continue to advance the paper so that a section of paper is long enough to pass through the printer cover once it is repositioned over the printer.

2.6.2 Paper Storage

The TM 262TM Auto TympTM utilizes a thermal printer, which requires a heat-sensitive paper to create an image. For maximum paper life, any spare rolls of paper should be stored as follows:

1)Store in the dark, i.e., in a drawer or cabinet

2)Do not store above 77°F (25°C)

3)Store at less than 65% relative humidity

The above recommendations are for the maximum paper life (greater than five years). Storing your TM 262 thermal paper at high temperatures or high humidity levels will only shorten the total paper life.

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2.7 PRETEST TYMPANOMETRY CHECKS

For your convenience, a test cavity is provided with your TM 262TM Auto TympTM. This test cavity enables you to quickly verify the proper calibration of your unit. Welch Allyn, Inc. strongly recommends that you make this quick check a part of your daily routine.

2.7.1 Calibration

To initiate the quick check, select the Tymp only TYMP mode and insert the probe (without a tip on it) into the 0.5 cm3 opening on the test cavity. See Figure 2-12.

NOTE

Since the TM 262 is designed to start automatically, it is important that the probe is inserted as quickly and as smoothly as possible. During the calibration check, the probe must be held carefully and without movement. Do not place the probe on the same counter as the instrument or any moving object during this check, as mechanical noise will be picked up by the probe and interfere with the calibration check.

0.5 cm3

5.0 cm3

2.0 cm3

FIGURE 2-12: Test Cavity

The calibration check will start automatically if the probe has been inserted into the cavity properly. This is confirmed by the green lamp changing from blinking to a steady condition. If the orange lamp is illuminated, the probe is not properly positioned within the cavity so that a large pressure leak exists. If the yellow lamp is illuminated, the probe tip has been occluded. In either case, remove the probe and wait for the blinking green lamp. Insert the probe once again. Clean the probe tip if necessary (see Section 3.2).

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When the test sequence is completed, the green lamp on the probe is no longer illuminated. Remove the probe from the test cavity and note that the green lamp is blinking once again. The display will indicate a flat line on the tympanogram along with the value of the test cavity next to the letters ECV (ear canal volume), i.e., 0.5. The letters NP will appear next to the labels cm3 and daPa and three dashed lines will appear next to the letters GR (gradient). Since the test cavity is a hardwalled cavity, the tympanogram should be a flat line, indicating that there is no mobility in the system. The TM 262TM Auto TympTM places the letters NP next to the cm3 and daPa headers to indicate that there is no peak compliance and, therefore, no peak pressure can be determined during the quick check. Also, since there is no compliance peak detected, it is not possible to calculate a gradient. Therefore, the TM 262 displays the dashed lines when a gradient calculation isn’t possible.

Using the same sequence, place the probe in the test-cavity opening labelled 2.0 cm3. Note that the display looks the same as with the 0.5 cm3 measurement, except for the value placed next to the letters ECV (2.0). If you wish, the same sequence can be followed with the 5.0 cm3 opening on the test cavity. To keep a record of this test-cavity-calibration check, simply press the PRINT ALL button on the front panel of the TM 262.

2.7.2 Altitude Adjustment

Since sound pressure will vary with altitude and barometric pressure, some variation from the 0.5, 2.0 and 5.0 cm3 readings may be observed. Your TM 262 is carefully calibrated at our factory, which is at approximately 250 feet above sea level. If you are located at an elevation of 1000 feet or higher, your instrument may need to be recalibrated to account for your elevation. It is not necessary to recalibrate for barometric pressure changes on a daily basis. Just keep in mind that a change in barometric pressure (i.e., from low to high or high to low) will slightly affect the test-cavity readings.

The altitude calibration adjustment allows for “corrections” to the Ear Canal Volume (ECV) measurement and test cavity volume measurement for variations due to altitude. Because the TM 262 is a pressuresensitive device which makes measurements relative to ambient air pressure, changes in air pressure due to weather or altitude will affect the Ear Canal Volume (ECV) read-out of the instrument. The slight pressure change resulting from changing weather conditions will usually yield volume read-outs within ±0.1 cm3 of the expected cavity value; however, pressure changes due to altitude can shift these cavity values by as much as 30%. These changes in pressure do not affect the accuracy of the compliance measurement system in any way.

But, many instrument operators prefer that their equipment give ECV values as they would appear at sea level. The altitude calibration mode allows the operator to adjust his/her Auto Tymp without the services of a qualified Welch Allyn Service Technician.

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TABLE 2-2: Altitude Correction

Altitude Correction

Altitude (ft.)	Altitude Table (cm3)
0 to 1,500	2.0
2,000 to 3,500	2.1 ± 0.1
4,000 to 6,000	2.2 ± 0.1
6,500 to 7,500	2.3 ± 0.1
8,000 to 9,000	2.4 ± 0.1
9,500 to 10,000	2.5 ± 0.1

The altitude calibration mode can only be entered when the TM 262 is powered up from its “off” state while the PROGRAM PROG mode button, is depressed. Hold the PROGRAM PROG button for approximately

five seconds.

STEP 1

When entering the altitude mode the display will read as follows: Altitude Mode

ECV 2.0 cm3 9.99 Standard

(E71) is displayed in the bottom right corner of the display until the probe is in the 2.0 cm3 cavity.

STEP 2

Place the probe into the 2.0 cm3 cavity provided with the instrument and check cm3 value against the altitude correction table for accuracy.

STEP 3

If the measured volume is not within the published table value ±0.1cc, then the operator should exit the altitude mode by pressing the PROGRAM PROG button and contact field service.

Providing the measured volume agrees with the published table ±0.1cc, the operator may proceed with the altitude adjustment.

STEP 4

With the probe still in the 2.0 cm3 cavity, select the PAGE PAGE button to enter the custom calibration mode. Custom will appear on the fourth line of the display.

STEP 5

The value now displayed in the cm3 display area is the volume measured and adjusted to the current altitude. If the value displayed is 2.0 cc, then the volume is adjusted to the current site. If the value is not 2.0 cc ±0.1, then press the SAVE M+ button to customize the volume measurement to the current altitude. The measured volume should now read 2.0 cc.

STEP 6

To exit the altitude mode, press the PROGRAM PROG button to return to normal mode.

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2.8 PRETEST AUDIOMETRIC CHECKS (Models with Audiometer Only)

2.8.1 Noise Recovery Period

Exposure to high levels of sound (e.g., unmuffled lawn mowers, loud music, gunfire) tends to create a Temporary Threshold Shift (TTS) which diminishes with time after exposure. Any subject tested soon after such exposure may exhibit a hearing loss that does not reflect his/her normal hearing threshold. This test procedure, therefore, generally prescribes a 16 hour interval between the last exposure to high-level sounds and the administration of any hearing test.

2.8.2 Elimination of Ambient Noise

Excessive noise in the test environment during audiometric testing, such as that produced by conversation, computers and public address systems reduces test validity because it tends to mask the test signals, particularly at the lower frequencies where earphone cushions provide less effective attenuation. An acoustically-treated room may be required if ambient noise reaches objectionable levels, i.e., sufficient to cause apparent hearing loss at the low frequencies. Also, earphone sound enclosures are available from Welch Allyn as an optional accessory. If the person being tested is in the same room as the audiometer, it is recommended that he/she be seated about three feet (one meter) away from the TM 262TM Auto TympTM.

Maximum permissible noise levels are specified by the American National Standards Institute—Criteria for Permissible Background Noise during Audiometric Testing, ears covered with earphones (S3.1-1991 revised). Table 2-3 shows the maximum background levels that can be present inside the room while a valid hearing test is being conducted. For more comprehensive information about hearing testing and hearing conservation, refer to the Bibliography.

TABLE 2-3: Permissible Noise Levels

Test Tone
Frequency (Hz)	125	250	500	750	1000 1500 2000 3000 4000 6000 8000
Test Room	34.0	22.5	19.5	21.5	26.5	26.5	28.0	33.5	34.5	38.0	43.5
Ears covered
maximum
permissible octave
band levels
Ears covered	29.0	17.5	14.5	16.5	21.5	21.5	23.0	28.5	29.5	33.0	38.5
maximum
permissible one-third
octave band levels

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2.9 BIOLOGICAL CHECK

To determine that your TM 262 is functioning properly, perform a daily check on a normal ear—your own if possible. This allows you to listen for the probe tone and the stimulus tone (during reflex) and determine if the air-pressure system is working properly. Keep a copy of your chart for a day-to-day reference in checking your TM 262.

If you purchased the TM 262TM Auto TympTM with audiometry, select the AUDIOMETRY AUD button located in the center section of the front panel. Note that the display changes to an audiogram format. The Hz

and Hz buttons allow you to select each frequency and the dB HL knob allows you to alter the intensity of each frequency. Position the test headset on your head so that each earphone is covering the appropriate ear (i.e., red is right and blue is left). Select the right earphone by pressing the front panel button labelled R and check for the following while depressing the present bar:

•Depressing the Hz button causes the frequency to change to a lower frequency, depressing the Hz button causes the frequency to change to a higher frequency.

•Each frequency or tone is pure, i.e., there is no distortion or crackling sound present.

•Rotating the dB HL knob in a clockwise direction increases in intensity of the tone.

•Rotating the dB HL knob in a counter-clockwise direction decreases the intensity of the tone.

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Specifications

STANDARDS:

IEC 601-1 Medical Electrical Equipment Requirements for Safety

CSA C22.2 No. 601-1-M90 Electromedical Equipment, Warnock Hersey Listed

ANSI S3.39-1987 Aural Acoustic Impedance Admittance (Type 3) IEC 1027-1991 Aural Acoustic Impedance/Admittance (Type 3) ANSI S3.6-1989 Audiometers (Type 4)

IEC 645-1 Pure Tone Audiometers (Type 4)

TYMPANOMETRY/REFLEX MODES:

Probe Tone: 226 Hz, ± 3%

Sound Pressure Level: 85.5 dB SPL, ± 2.0 dB, measured in a 2.0 cm3 coupler

Harmonic Distortion: <5%

Admittance (Compliance) Range: 0 to 1.5 cm3

0 to 3.0 cm3

NOTE:

1.The range is automatically selected based upon the amplitude of the compensated (tymp only) tympanogram.

2.The maximum uncompensated (ECV + tympanogram peak) admittance (compliance) range is 0 to 5.0 cm3.

3.ECV/cavity limits for initiating pressurization is 0.2 to 6.0 cm3. Compliance Accuracy: ± 0.1 cm3 or ± 5%, whichever is greater

PNEUMATIC SYSTEM

Pressure Range: +200 to –400 daPa

NOTE:

1.1 daPa = 1.02 mm H20

2.Pressure sweeps to at least –100 daPa. To save test time, pressure sweep stops once tympanogram returns to baseline after –100 daPa.

3.Full pressure sweep for 6 cm3 from sea level to 7000 ft. altitude with no leak.

Pressure Accuracy: ±10 daPa or ±15%, whichever is greater

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Rate of Sweep: 600 daPa/sec except near tympanogram peak where sweep rate slows to 200 daPa/sec to provide better definition of peak compliance.

Direction of Sweep: Positive to negative

Tympanometric Test Time: approximately one second

NOTE:

High compliance tympanograms will take somewhat longer

Gradient: Tympanogram pressure width at 50% of peak compliance.

ACOUSTIC REFLEX STIMULI:

Frequencies: 500, 1000, 2000, and 4000 Hz

Accuracy: ±3%

Total Harmonic Distortion: <5% Rise/Fall Time: 5 to 10 msec Output Levels:

IPSI: 500 and 4000 Hz:80, 90, 100 dB HL 1000 and 2000 Hz: 85, 95, 105 dB HL

NOTE:

1.Ipsi stimuli are time multiplexed with probe tone (106 msec ON, 53 msec OFF).

2.Stimuli are presented at lowest level first. If there is no response, the intensity is increased by 10 dB until a response is detected or the maximum dB HL is reached.

Pressure: Automatically set to pressure at peak compliance with an offset of –20 daPa.

Reflex Determination: Compliance change of 0.05 cm3 or greater.

Reflex Test Time: 1 to 12 seconds depending upon the number of ipsi test frequencies selected (four maximum) and intensity required.

Probe LED Indicators:

Steady yellow: occlusion

Blinking green: ready to start testing Steady green: test in progress Steady orange: leak

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AUDIOMETRY MODE (Model No. 26230, No. 26230-RS, No. 26235 and No. 26235-RS only— marked “Version 4”)

Frequencies: 125, 250, 500, 750, 1000, 1500, 2000, 3000, 4000, 6000, 8000 Hz

Accuracy: ± 3%

Total Harmonic Distortion: < 3% (125 to 3000 Hz measured acoustically at maximum dB HL; 4000 & 6000 Hz measured electrically)

Intensity Levels: 125 Hz: –10 to 50 dB HL 500 to 6000 Hz: –10 to 90 dB HL 250 and 8000 Hz: –10 to 70 dB HL

NOTE:

An additional +10 dB is available per frequency via the +10 dB button.

Accuracy: 125 to 4000 Hz ±3 dB 6000 and 8000 Hz ±5 dB

Step Size: 5 dB

Signal-to-Noise Ratio: > 70 dB in 1/3 octave;

less than –10 dB HL for levels less than 60 dB HL

Rise/Fall Time: 20 to 50 msec

Tone Format (tone is normally off until present bar is depressed):

Continuous: steady when present bar is depressed Pulsed: 2.5/sec (i.e., 200 msec ON, 200 msec OFF) FM (frequency modulated): 5 Hz, ±5%

TRANSDUCERS

IPSI: Welch Allyn design

Audiometric Headset: Pair TDH-39 earphones with MX41AR cushions (60 ohms impedance)—Models No. 26230, No. 26230-RS, No. 26235 and No. 26235-RS only (marked “Version 4”)

PRINTER

Paper Roll Length: approximately 80 feet (960") Tests/Roll: Tymp and Reflex = 420 tests or 210 people

Tymp and Reflex plus one audiogram = 230 tests or 115 people

Speed: approximately 1.5 minutes to print three screens (including audiogram).

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