Biomedical subjects

P Howell

Publications and source records attributed to P Howell.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Changes in voice level caused by several forms of altered feedback in fluent speakers and stutterers.

Speakers change the level of their voice when they listen to noise or hear their own speech amplified: When noise level is increased the voice becomes louder, whilst the response to speech amplification is a reduction of voice level. The question posed here is whether, when the level of various sounds concurrent with vocalisation is raised, the direction of the vocal level response is like that to the speaker's speech or like that to noise. Voice level was measured in response to speech, white noise, delayed auditory feedback, frequency-shifted speech, and noise created by an "Edinburgh masker". Selection of these sounds was governed by the role they have played in the explanation and treatment of stuttering. Fluent speakers and stutterers increased voice level when played delayed auditory feedback, the Edinburgh masker, or white noise; they reduced the level slightly in the remaining conditions. These results are used to assess auditory feedback monitoring accounts of the speech behavior of fluent speakers and stutterers, and some implications for the treatment of stuttering are pointed out.

Adult↗

PubMedDate not supplied

Are two muscles needed for the normal functioning of the mammalian middle ear?

Why do two muscles occur in the middle ear of most mammals? In this article selected explanations as to why two muscles occur are critically evaluated. It is argued that these explanations are not compelling. Data are then reviewed that indicate that the tensor tympani has no function to fulfil in the normal operation of the middle ear.

Animals↗

PubMedDate not supplied

Middle ear muscle activity during vocalization in normal speakers and stutterers.

Although it has been established that the middle ear muscles contract prior to vocalization, it is not known which muscle is mainly responsible for this activity. Also, there have been contradictory reports about whether this activity in stutterers differs from that of normal speakers. To tackle these questions, extratympanic pressure measurements prior to vocalization are reported for normal speakers and stutterers. This measure allows activity deriving from the two middle ear muscles to be differentiated and for the temporal course to be followed more accurately than by impedance measurement. To establish which muscle is primarily responsible for the pre-vocalization activity, the measured pressure changes prior to vocalization are compared with activity measured in tasks known to involve the stapedius or tensor tympani alone. These data show that in normal speakers and stutterers, the activity that is measured prior to vocalization resembles that of the tensor tympani. Contrary to other reports, there is no difference between normal speakers and stutterers in the time course of this activity.

Humans↗