Frans Debruyne

Acoustic analysis of the speaking voice after thyroidectomy

Voices of 47 female patients were analyzed before and after thyroidectomy, with preservation of the recurrent and superior laryngeal nerves and normal vocal fold motility during the observation period. A mean decrease of the speaking fundamental frequency (SFF) of 12 Hz was found on day 4; in 8 patients the postoperative vocal pitch was more than 2 semitones lower. The distance between the highest and lowest F0 during speaking was diminished (speech was more monotone) and the vocal jitter was elevated. In the frequency spectrum, there was a diminished prominence of the harmonics. The other spectral parameters (as the slope of the spectrum and the H1/H2 ratio) were unchanged. All changes had disappeared the fifteenth day, except for a lower SFF (> 2 semitones) in 2 cases. It is concluded that after normal dissection of the laryngeal nerves, and in the absence of vocal fold paresis, other reasons for voice changes immediately after thyroidectomy remain: alterations in the neck muscles, in the laryngeal mucosa, and in the patients general condition. Although the effects seem limited and of short duration, knowledge of them is helpful when informing the patient before thyroid surgery.

Acoustic analysis of tracheo-oesophageal versus oesophageal speech

In order to evaluate the vocal quality of tracheo-oesophageal and oesophageal speech, several objective acoustic parameters were measured in the acoustic waveform (fundamental frequency, waveform perturbation) and in the frequency spectrum (harmonic prominence, spectral slope). Twelve patients using tracheo-oesophageal speech (with the Provox valve) and 12 patients using oesophageal speech for at least two months, participated. The main results were that tracheo-oesophageal voices more often showed a detectable fundamental frequency, and that this fundamental frequency was fairly stable; there was also a tendency to more clearly defined harmonics in tracheo-oesophageal speech. This suggests a more regular vibratory pattern in the pharyngo-oesophageal segment, due to the more efficient respiratory drive in tracheo-oesophageal speech. So, a better quality of the voice can be expected, in addition to the longer phonation time and higher maximal intensity.

Arteria lusoria identified on preoperative CT and nonrecurrent inferior laryngeal nerve during thyroidectomy: A retrospective study

To evaluate surgical identification of nonrecurrence of the inferior laryngeal nerve (NRILN) during thyroidectomy in patients with an aberrant subclavian artery (a. lusoria) as seen on CT.

Binaural Interaction in Early, Middle and Late Auditory Evoked Responses

Binaural interaction of early, middle and late auditory potentials (1-250 ms) was investigated by comparing peak-to-peak amplitudes after diotic stimulation with the computer sum of the right and left monaural reactions. While absent in waves I and III of the brainstem response, binaural interaction or fusion appears in wave V and in the middle latency response, and seems to be greatest in the cortical response N1P2N2.

Hearing in congenital hypothyroidism

The hearing profile of children with congenital hypothyroidism was studied in 45 patients with thyroid gland agenesis, hypogenesis or dyshormogenesis, during adequate substitution therapy. Preliminary, secretory otitis media was found in 6 patients under the age of 6 years; in these children, hearing assessment was performed after cure of the middle ear effusion. Hearing threshold was measured either by conventional pure-tone audiometry or conditioned orientation reflex audiometry according to the patients age (above and below 4 years). In 36 patients (80%) the auditory thresholds were normal; in the remaining 9 patients (20%) a sensorineural hearing loss of different degree was detected; in 5 cases (11%) the deafness was important and required auditory rehabilitation, with the use of a hearing aid in 4 of them. No relation could be found between hearing acuity and bone age at diagnosis of hypothyroidism or aetiology of thyroid dysfunction. It is concluded that in about one tenth of the children with congenital hypothyroidism a substantial deafness persists. The sensorineural nature of the hearing loss is in agreement with reported histological findings in congenital hypothyroid animals, where an immature development of the organ of Corti including hair cells and tectorial membrane has been observed.

Longitudinal voice changes: facts and interpretation.

To study intraindividual vocal changes over time, a longitudinal research design is preferred. However, this procedure reveals many restrictions concerning methodology and interpretation, especially in cases of (semi)retrospective studies. This is illustrated by an investigation of the voices of 20 male Dutch-speaking reporters of the Belgian Radio Broadcasting service. These men read the same text they did 30 years previously for a digital registration. After having copied the high-quality archival recordings digitally, the results of the acoustical analysis of both recordings (recent and archival) were compared. This was done to search for the contribution of aging. In this article we report on the results of the speaking fundamental frequency (SFF) and the standard deviation of the SFF (SFFsd) as a measure of intraindividual variability, and the voice onset time (VOT). Results indicate that, in connected speech, SFF decreased, SFFsd became more restricted, and the VOT increased strongly. The interpretation of the results compels us to conclude that it is extremely difficult to define the specific effect of aging alone, since it is only one element among many others, including methodological concerns.

Speaking fundamental frequency in monozygotic and dizygotic twins

The speaking fundamental frequency (SFF) and the intraindividual variation of the SFF during the reading of a Dutch standard text were measured in 30 female monozygotic twins (MT) and 30 dizygotic twins (DT), aged 15-29 years. A control group was created that consisted of 30 nonrelated paired individuals of equal age. Studying the intrapair correlation coefficients it seemed that the SFF was similar to a greater degree in MT and to a lesser degree in DT, while there was no correlation at all in nonrelated peers. These results are compatible with a genetic basis for the SFF. On the other hand, the intraindividual variation of the SFF was highly similar in MT and in DT (but not in nonrelated peers), so that for this parameter it was not possible to discern the influences of genetic disposition and shared environment.

Changes in spectral measures and voice-onset time with age: a cross-sectional and a longitudinal study

In this study, we searched for changes in spectral features (during the sustained vowels [a] and [i]) and the voice onset time (VOT, of [pa] and [ka]) of the ageing voice. A longitudinal study (on 20 participants) and a cross-sectional study (on 265 participants) were conducted. The spectral parameters under consideration were: the difference in amplitude between the first and the second harmonic, the energy difference between the frequency band below 1 kHz and 2-4 kHz, and the energy difference between < 1 kHz and 4-5 kHz. The VOT was also measured. Comparing five age bands of men and women, the cross-sectional study revealed a stronger H2 relative to H1 for women above 60 years pronouncing both vowels [a] and [i]. A relatively stronger spectral level was found between 4 and 5 kHz in elderly men and women (60+) for [i] compared to young men and women (20-29 years). Significant differences in the longitudinal study were not identical to those of the cross-sectional study. After a time interval of 30 years, 20 men produced a relatively weaker 2- to 4-kHz part of the spectrum and the VOT became much longer. It was impossible to attribute the changes purely to the process of ageing. Situations and emotions also play an important role and contribute to the different findings of the two groups of participants under consideration.

One-Year Follow-Up after Tympanostomy Tube Insertion for Recurrent Acute Otitis media

In a prospective study, 126 children were followed for 1 year after the placement of tympanostomy tubes especially for recurrent acute otitis media. About 7 in 10 children remained free of middle ear infection and 1 in 10 showed frequent (i.e. 3 or more) episodes of otorrhea during the follow-up period. However, the most conclusive observation was that the otorrhea episodes were not equally distributed over the different ages: they were markedly more frequent in the group younger then 2 years old, although the prestudy infection rate was similar in all age groups. Furthermore, the incidence of middle ear infection was positively correlated with upper respiratory infection but not with other variables such as prestudy spontaneous perforations, contents of the middle ear, presence of the tube at the end of the study, and swimming habits. It seems that middle ear infection with ventilation tubes in place is influenced by age and upper respiratory infection as it is for acute otitis media in the population as a whole.

Lateral sinus thrombosis in the eighties

In spite of the increasing use of more efficient medical therapy, different types of otogenic intracranial complications continue to occur. A detailed description of two cases of lateral sinus thrombosis illustrates that its present-day clinical course can differ from the traditional clinical picture of the disease.