"what if", I wondered, "he could not hear himself talking." "Would he speak better?" I retrieved a Walkman from my gym bag in my office and put the headset on the patient and set the radio channel between stations on static. Much to my amazement, his voice was louder and speech clearer. I immediately audio-taped him to provide him feedback with a plan to video-tape him on his next visit.
My experience with that patient set me on a little odyssey of learning about auditory masking and **Lombard effect on speech and voice. My investigating led me to the stuttering literature of the 60's and 70's, which included reference to masked auditory feedback, which generally used noise of some sort of sufficient intensity to block the auditory feedback of the speaker's own voice to his or her ears. In 1979, the Edinburgh Masker was developed by a stuttering therapist and her physician husband. The device was available to persons who stutter up until the 1990's when it was no longer manufactured.
Various devices have continued to be available to persons who stutter, some using auditory masking and others delayed auditory feedback ( imagine a bit of an echo in your ear). The use of these techniques for persons with Parkinson's is a bit of a more recent phenomena.
I continue to use auditory masking during my initial evaluation of patients with Parkinson's, and because I also video-tape all of my patients, the difference in speech with and without the effect of masking can serve as a great tool for feedback and goal setting. The average increase in loudness I notice for most patients is 10db above their normal speaking voice. This improvement in loudness which requires no particular instruction from me, can also help re-enforce to the person that the "instrument" ( i.e. their voice" is working, but that they no longer are mastering its use.
If you or someone close to you has been struggling with voice and speech changes related to Parkinson's Disease, the future is bright. Device interventions are springing up all over. Some as small as a hearing aid and others interfacing with an iPod. It is unlikely that these devices will take the place of formal speech therapy programs or vocal function exercises, which can often benefit speech and swallowing, but, what they may do is provide a quick improvement in day to day communication along with an improved sense of well being. When talking is no longer a struggle, it is likely that many persons will be even more willing, ready, and able to continue with voice strengthening programs on their own.
**Lombard effect or Lombard reflex is the involuntary tendency of speakers to increase their vocal effort when speaking in loud noise to enhance the audibility of their voice. In addition to loudness, this effect may also influence rate.
Below is a former patient demonstrating some of the changes that auditory masking can yield.