Decrease In F0 Research Articles

Shifts in fundamental frequency and articulation resulting from intoxication

Two groups of subjects were administered controlled doses of alcohol while breath alcohol concentration (BrAC) measurements were made at regular intervals. They were recorded reading a 30-s passage when they reached preset BrAC windows. Fundamental frequency measurements were calculated and compared for sober (0.00 BrAC) and intoxicated (0.12 BrAC) productions. The number of misarticulations occurring during the readings also were assessed. In the first study, subjects were grouped on the basis of whether they were rated as sounding intoxicated at 0.12 BrAC (ratings were performed by 50 auditors using a 5-pt. scale). Subjects who sounded intoxicated were placed in one group, while those that did not were placed in a second. The first group showed a consistent, but statistically nonsignificant decrease in F0 as a result of intoxication; group 2’s F0 changes were not consistent. In addition, the first group showed a higher mean increase in misarticulations than did group 2. The second population was grouped by drinking level (heavy, medium, or light); none showed a statistically significant change in F0. Moreover, misarticulations increased (nonsignificantly) as drinking level increased. The results will be correlated with data from other studies. [Research supported by NIH.]

A six-month post-electrical stimulation effect in speech production

This study documents an unusual effect in cochlear implant patients’ speech 6 months following electrical stimulation. Spectrographic measures were made of 45 phonemically balanced words, recorded before and after electrical stimulation (1 day, 1–6 months, and 1 year). Five Nucleus multichannel cochlear implant patients with different deafness histories participated. A prelingually deafened patient showed a steady decrease in F0 and an increase in duration of several (supra) segmental parameters after electrical stimulation. At 6 months, F0 reached its lowest value and syllable and vowel durations reached their highest values. A postlingually deafened reimplantation patient also showed cusps 6 months post Nucleus: F0 increased for the one and only time, aspiration/frication durations in medial and final syllable positions became abnormally long and then corrected at 1 year, and a long closure was introduced , which diminished at 1 year. The possibility of a critical change in modification of F0 and duration aspects of speech at 6 months is being investigated in other patients. Implications of such a change will be discussed. [Work supported by NIDCD.]

The influence of consonant environment on F0 from voicing onset to vowel target in the speech of children

Although research on adult speech has manifested systematic effects of consonant environment on the fundamental frequency (F0) of vowels, little is known about the nature of these influences in children. In order to determine the effects of consonant environment on F0 in children, three girls and three boys between 8 and 9 years recorded five repetitions each of voiceless aspirated /ph,th,kh/ voiceless unaspirated /sp,st,sk/, and voiced /b,d,g/ stops in combination with the vowels /i,e,u,o,a/. Fundamental frequency was measured for the first five glottal periods and vowel target, and voice onset time (VOT) was determined for each utterance. The findings for VOT revealed nearly identical results for voiceless unaspirated stops and voiced stops, whereas differences between voiceless unaspirated and voiceless aspirated stops for labial, alveolar, and velar features were 61, 65, and 59 ms, respectively. Despite the similarity in VOT between voiceless unaspirated and voiced stops, F0 contours of voiceless unaspirated stops were more similar to voiceless aspirated than voiced stops. In general, there was a decrease in F0 from the first glottal period to the second glottal period for all voicing conditions. Moreover, F0 was usually higher in the environment of voiceless stops than voiced stops, although this was not unanimous across subjects. The findings will be discussed relative to developmental and coarticulatory processes, and sex differences. [Work supported in part by NINCDS.]

The effects of linguistic context on temporal and F0 properties of speech

Research examining acoustic properties of speech frequently use isolated syllables or syllables embedded in carrier phrases for analysis. Although it has been argued that these contexts represent rather limited speech situations [N. Umeda, J. Acoust. Soc. Am. 70, 350–355 (1981)], it is not clear that the influences of these contexts on speech are comparable. In order to determine the effect of these contexts on several acoustic properties of speech, three male subjects recorded repetitions of voiceless aspirated /ph,th,kh/ and voiced /b,d,g/ stops in combination with the vowels /i,e,u,o,a/ in both isolated CVC syllables and CVC syllables embedded in carrier phrases. Fundamental frequency (F0) was measured for the first five glottal periods and voice onset time (VOT) was determined for each utterance. The three acoustic properties selected for purposes of comparison were VOT, the percent decrease in F0 from the first to second glottal period, and the absolute value of F0 for the first five glottal periods. The results revealed that the greatest differences in VOT between isolated syllables and syllables produced in carrier phrases were for voiceless stops, i.e., 37 ms or greater across place of articulation, whereas for the F0 properties variation between these contexts was greatest for voiced stops. In general, however, the findings for F0 were similar in direction to results obtained in fluent reading. [Work supported in part by NINCDS.]

Does short-term endotracheal intubation affects the acoustic characteristics?

Endotracheal intubation can produce various degrees of temporary and sometimes permanent damage to the laryngotracheal mechanism. Recent development of computer based voice analysis technology can now detect a minute changes in acoustic waveforms which a normal human ear cannot. In the study we compared and analyzed the acoustic waveforms of 35 patients undergoing surgery under intubation anaesthesia. The aim of the present series is to analyze the effects of short term intubation with computerized voice laboratory. Values of acoustic waveforms obtained from 35 patients were compared 48 hours after the short term endotracheal intubation anaesthesia. The comparisons were made in terms of perturbation (jitter and shimmer), harmonic- to noise ratio (HNR) and fundamental frequency (F0). The pre-intubated voice characteristics when compared with the post-intubation group did not reveal any statistical difference (P>0.05). However, there was only a minimal decrease in F0. The study revealed that, short term intubation anaesthesia does not alter the acoustic characteristics. The analysis of acoustic waveforms is a non invasive technique that helps to evaluate the effects of tracheal intubation on laryngeal function, a technique that warrants further evaluation.