The Accepted Percentage Hearing Loss for different types of deafness can be calculated by using air conduction, bone conduction, various combinations of the two or a special formula. The relevant rules are summarised in Table 7.1.2 and in the text which follows it. (The “types” mentioned in Table 7.1.2 refer to the combination of hearing losses as described in the preceding text and not necessarily to named accepted conditions.)
Table 7.1.2 sets out which HTLs (air or bone) from the audiogram are to used in calculating APHL.
Procedural Table 7.1.2 Combined male and female symbol
TYPES OF AUDIOGRAM TO BE USED
For RightHTL use: For LeftHTL use:
Type 1 Bilateral mixed deafness Air Air
Type 2 Right mixed deafness Air 0 (zeros)
Type 3 Left mixed deafness 0 (zeros) Air
Type 4 Bilateral sensorineural deafness Bone Bone
Type 5 Bilateral sensorineural deafness with right conductive deafness Air Bone
Type 6 Bilateral sensorineural deafness with left conductive deafness Bone Air
Type 7 Bilateral conductive deafness See Substep 3A
Type 8 Bilateral conductive deafness with right sensorineural deafness Air Air
Type 9 Bilateral conductive deafness with left sensorineural deafness Air Air
Type 10 Left conductive deafness with right sensorineural deafness Bone Air
Type 11 Right conductive deafness with left sensorineural deafness Air Bone
Type 12 Right conductive deafness See Substep 3A
Type 13 Right sensorineural deafness Bone 0 (zeros)
Type 14 Left sensorineural deafness 0 (zeros) Bone
Type 15 Left conductive deafness See Substep 3A
Information and instructions concerning the use of bone HTLs are to be found on the next page, and apply in all cases where “Bone” appears in this table or in which reference is made to Substep 3A.
No age adjustment permitted for this table
Information and instructions concerning the use of bone HTLs
1. Whenever the use of bone conduction HTL values is specified but if it is not practicable or appropriate to obtain bone conduction HTL values as a result of any of the reasons described on page 108, air conduction HTL values may be used instead.
2. Threshold of Reliability.
Bone conduction HTLs in excess of 60 deciBels are generally unreliable. At the 500 Hz frequency, bone conduction HTLs in excess of 45 deciBels are unreliable.
Thus a set of thresholds of reliability for bone HTLs is defined as follows:
for 500 Hz 45 deciBels
for 1000 Hz 60 deciBels
for 1500 Hz 60 deciBels
for 2000 Hz 60 deciBels
for 3000 Hz 60 deciBels
for 4000 Hz 60 deciBels
Figures in excess of the threshold of reliability for bone conduction are not used in calculating the impairment due to hearing loss.
For sensorineural hearing loss, whenever the bone conduction HTL exceeds the threshold of reliability, the air conduction HTL for that frequency and side is to be used instead of the bone conduction HTL.
For conductive hearing loss, whenever the bone conduction HTL exceeds the threshold of reliability, the threshold figure for that frequency and side is to be used instead of the bone conduction HTL.
The above arrangement gives to the veteran the benefit of any doubt relating to the intrinsic unreliability of bone HTLs.
Substep 3A: Calculation of accepted hearing loss for types 7, 12, and 15.
Substep 3A applies to these types of accepted hearing loss:
Type 7 Bilateral Conductive deafness
Type 12 Right Conductive deafness
Type 15 Left Conductive deafness.
For each type, one of two methods is to be used:
Method 1 is to be applied if both air and bone conduction HTLs are available. In this case both the air and bone conduction HTLs are calculated and a formula is applied. In calculating the bone conduction HTL, if the bone conduction HTL exceeds the threshold of reliability, the threshold figure for that frequency and side is to be used instead of the bone conduction HTL.
The terms “air conduction PLH (Percentage Loss of Hearing)” and “bone conduction PLH” are used in the formulas. These are calculated in a way similar to that in which APHL is calculated for other types of deafness.
Method 2 is to be applied if only air conduction HTLs are available and if it is not practicable or appropriate to obtain bone conduction HTL values as a result of any of the reasons described on page 108.
Type 7. Bilateral conductive deafness
Method 1 (to be applied if both air and bone conduction HTLs are available):
First:
Air Conduction PLH is to be calculated using right and left air conduction HTL values, and
Bone Conduction PLH is to be calculated using right and left bone conduction HTL values.
Next:
Using the air conduction and bone conduction PLHs, the PLH for bilateral conductive deafness is calculated by applying the following formula:
Start formula, conductive PLH equals, start fraction, open parentheses, A minus B, close parentheses, times 100, over 100 minus B, end fraction, end formula
(where “A” is air conduction PLH, and “B” is bone conduction PLH).
No adjustment for age is to be applied to the results of applying the formula. That result is the age adjusted PLH for bilateral conductive deafness.
Go to Step 5 (on page 122).
Method 2 (to be applied if only air conduction HTLs are available and if it is not practicable or appropriate to obtain bone conduction HTL values as a result of any of the reasons described on page 108.
PLH is to be calculated using measured right and left air conduction HTL values. The formula is not applied and so age adjustment is required.
Go to Step 4 (on page 120).
Type 12. Right conductive deafness
Method 1 (to be applied if both air and bone conduction HTLs are available):
First:
Air Conduction PLH is to be calculated using right air conduction HTL values and taking the left air conduction HTL values all to be zero; and
Bone Conduction PLH is to be calculated using right bone conduction HTL values and taking the left bone conduction HTL values all to be zero.
Next:
Using the air conduction and bone conduction PLHs, the PLH for right conductive deafness is calculated by applying the following formula:
Start formula, conductive PLH equals, start fraction, open parentheses, A minus B, close parentheses, times 100, over 100 minus B, end fraction, end formula
(where “A” is air conduction PLH, and “B” is bone conduction PLH).
No adjustment for age is to be applied to the results of applying the formula. That result is the age adjusted PLH for right conductive deafness.
Go to Step 5 (on page 122).
Method 2 (to be applied if only air conduction HTLs are available and if it is not practicable or appropriate to obtain bone conduction HTL values as a result of any of the reasons described on page 108).
PLH is to be calculated using right air conduction HTL values and taking the left air conduction HTL values all to be zero. The formula is not applied and so age adjustment is required.
Go to Step 4 (on page 120).
Type 15. Left conductive deafness
Method 1 (to be applied if both air and bone conduction HTLs are available):
First:
Air Conduction PLH is to be calculated using left air conduction HTL values and taking the right air conduction HTL values all to be zero; and
Bone Conduction PLH is to be calculated using left bone conduction HTL values and taking the right bone conduction HTL values all to be zero.
Next:
Using the air conduction and bone conduction PLHs, the PLH for right conductive deafness is calculated applying the following formula:
Start formula, conductive PLH equals, start fraction, open parentheses, A minus B, close parentheses, times 100, over 100 minus B, end fraction, end formula
(where “A” is air conduction PLH, and “B” is bone conduction PLH)
No adjustment for age is to be applied to the results of applying the formula. That result is the age adjusted PLH for left conductive deafness.
Go to Step 5 (on page 122).
Method 2 (to be applied if only air conduction HTLs are available and if it is not practicable or appropriate to obtain bone conduction HTL values as a result of any of the reasons described on page 108).
PLH is to be calculated using left air conduction HTL values and taking the right air conduction HTL values all to be zero. The formula is not applied and so age adjustment is required.
Go to Step 4 (on page 120).
Table 7.1.3 500 Hz Combined male and female symbol
Values of percentage of loss of hearing corresponding to given hearing threshold levels in the better and worse ear at 500 Hz
Note: the worse ear is the one with the higher value HTL!
APHL may be age adjusted
Step 4: Make any necessary age adjustment.
Calculate the veteran’s age (in completed years) at the date of the audiogram being used. For example, a veteran whose 67th birthday fell on the day after the audiogram was performed, was 66 on the date of the audiogram.
Determine the appropriate adjustment for presbyacusis from Table 7.1.9.
Table 7.1.9 includes different values for both males and females and has separate columns for bilateral accepted hearing losses and for unilateral accepted hearing losses.
The value obtained from Table 7.1.9 is subtracted from the PLH.
The tabular format below shows how the work can be set out. The “adjustment for presbyacusis” (obtained from Table 7.1.9) is to be subtracted from the APLH (obtained in Step 3). The result of this subtraction is the “age adjusted hearing loss”.
Accepted Hearing Loss
FREQ Hearing Levels (dB) Loss
(Hz) Right Left (%)
500
1000
1500
2000
3000
4000
APHL
=
adjustment for presbyacusis
=
from Table 7.1.9
age adjusted hearing loss
=
PLHB = Percentage bilateral loss of hearing due to age and is dependent upon both age and gender.
PLHU = Percentage unilateral loss of hearing due to age and is dependent upon both age and gender.