Since I started taking vitamin B-1 a year and a half ago, my fluency has been very good. Even in stressful speaking situations I’m very fluent. But there’s one situation in which I stutter severely: when there’s loud background noise, such as at parties.
The “conventional wisdom” is that stutterers talk fluently when we can’t hear our voices, so loud background noise makes us fluent.
Garber and Martin (1977)[ref]Garber, S., & Martin, R. 1977. Effects of noise and increased vocal intensity on stuttering. J Speech Hear Res. 1977 Jun;20(2):233-40.[/ref] compared two parameters, for four conditions:
- 100 dB “broadband noise.” I presume they meant white noise.
- Speaking at a normal vocal volume, or speaking 12 dB louder.
The results were:
- Speaking loudly without noise increased stuttering 8%.
- Speaking at a normal vcoal volume with noise reduced stuttering 34%.
- Speaking loudly with noise reduced stuttering 35%.
Kalinowski (1992) found that 85 dB white noise reduced stuttering about 35%.[ref]Kalinowski, J., Armson, J., Stuart, A., Graco, V., & Roland-Mieskowski, M. (1993). Effects of alterations in auditory feedback and speech rate on stuttering frequency. Language and Speech, 36, 1-16.[/ref] In the same study they found that DAF and FAF each reduced stuttering about 70%.
Block (1996) found that the Edinburgh Masker, which synthesizes a sine wave to match the user’s fundamental frequency of phonation, reduced stuttering 50%.[ref]Block, S., Ingham, R.J., & Bench, R.J. (1996). The effects of the Edinburgh Masker on stuttering. Australian Journal of Human Communication Disorders, 24, 11-18.[/ref] Dewar (1979) found that the effectiveness of the Edinburgh Masker didn’t wear off over six months, and that users set the volume on average at 77.6 dBA.[ref]Dewar, A., Dewar, A.D., Austin, W.T.S., Brash, H.M. (1979) The Long Term Use of an Automatically Triggered Auditory Feedback Masking Device in the Treatment of Stammering. British Journal of Disorders of Communication, 14(3), 19-26.[/ref]
Why does white noise and sine waves increase fluency, when parties make me stutter more?
One possibility is that talking louder makes me disfluent. But Garber and Martin (1977) found only an 8% increase in stuttering when stutterers speak 12 dB louder. That seems about right to me.
Another possibility is that different kinds of background noise are different. It appears that white noise reduces stuttering about 35%, a sine wave mimicking phonation reduces stuttering about 50%, and DAF and FAF each reduce stuttering about 70%. It appears that the ideal is to hear your own voice altered in a way that doesn’t change your recognition that it’s your voice.
Going the other way, loud music and people talking loudly around me increases my stuttering. The worst for me is a television blaring in a room. Televisions grab my attention and distract me from the conversation. A loud conversation close behind me also makes me unable to pay attention to a conversation partner in front of me. I find music easier to ignore.
To reduce this problem I carry hearing protection with me at all times. I prefer Howard Leight Laser Lites. These drop background noise 33 dB. When I put these in at a party, I immediately talk fluently again. I can also hear what a person is saying, as the hearing protection blocks noise frequencies but lets vocal frequencies pass.
Telex makes wireless headsets with active noise-reduction headphones and noise-cancelling microphones. I’d like to take these headsets to a party, hand a headset to a person I wanted to talk to, and we’d both hear the loud party drop away while we talked to each other clearly at a normal conversational level. The Telex headsets cost about $5,000 for a pair. I tried to rig the same thing using $100 active noise-reduction headphones with microphones from a Bluetooth motorcycle communication system. It almost worked! :-)