Military Noise-Induced
Noise-induced loss from military service: gunfire, explosions, aircraft, and heavy vehicles. Both ears have a deep dip from 3 to 6 kHz, worse in the left, the ear nearest the muzzle for a right-handed shooter. Tinnitus is on, since it’s the most common disability the VA compensates. From 2003 to 2015 many service members wore 3M Combat Arms earplugs that lawsuits said could loosen without the wearer noticing; 3M settled them for $6 billion in 2023 without admitting fault.
Summary
- Severity
- Mild40 dB HL
- Most loss at
- 4 kHz · 70 dB
Degree of the worse ear, averaged over all eight frequencies, on the scale used by U.S. audiologists (ASHA)
Pure-tone average (PTA)
- Left ear
- 18dB
- Slight
- Right ear
- 13dB
- Normal
What’s a pure-tone average?
Pure-tone average is the quietest tone each ear can just hear, averaged across three pitches central to speech (500 Hz, 1 kHz, and 2 kHz). It’s the single number U.S. audiologists use to sum up an audiogram. 15 dB or lower is normal hearing, and every 10 dB higher means sounds need to be about twice as loud to be heard. Internationally, the World Health Organization averages four pitches, adding 4 kHz, so where high pitches have more loss its number comes out higher.
Thresholds by frequency
| Hz | L | R |
|---|---|---|
| 250 | 10 | 5 |
| 500 | 10 | 10 |
| 1k | 15 | 10 |
| 2k | 30 | 20 |
| 3k | 60 | 40 |
| 4k | 70 | 50 |
| 6k | 70 | 55 |
| 8k | 55 | 40 |