Release: September 9, 2001
Contact: Kenneth Satterfield(703) 519-1563[email protected]303-228-8460 (9/7-9/12)
SURGERIES FOR SLEEP APNEA, SINUSITIS, CAN HAVE A POSITIVE IMPACTON VOICE RESONANCE
Researchers maintain that changes move towards an acoustic "norm."
Denver, CO -- Surgeries that alter the structures of the upper airway are commonly performed otolaryngologic procedures. Surgical correction of septal deviation and turbinate hypertrophy recommended for nasal obstruction and chronic sinusitis. Uvulopalatopharyngoplasty (UPPP), often in conjunction with septoplasty and tonsillectomy, is performed in the management of obstructive sleep apnea. These procedures, however, have the potential to affect vocal quality by altering the resonant characteristics of the vocal tract. These resonances, measured specifically as formant frequencies, are defined by the size and shape of the acoustic spaces of the vocal tract, generally divided into the oral, nasal and pharyngeal cavities. Formant frequencies are manipulated by creating varying degrees of constriction of the airflow using the lips, mandible, tongue, velopharyngeal port and pharyngeal walls. The formant frequencies specify the vowels that are produced and significantly contribute to the overall vocal quality.
Previous studies have been undertaken to assess the impact of upper airway surgery on the voice. However, these studies have generally been limited in scope or sample size. Now, a team of New York researchers has assessed acoustic characteristics, including relative formant amplitude, in a larger group of patients before and after upper airway surgery.
The authors of the study, "The Effect of Upper Airway Surgery on Voice," are Alison Behrman, PhD, and Mark J. Shikowitz, MD, both from the Schein Voice and Laryngeal Center, Department of Otolaryngology and Communicative Disorders, Long Island Jewish Medical Center, New Hyde Park, NY, and Seth Dailey, MD, from the Albert Einstein College of Medicine, Bronx, NY. Their findings were presented on September 11 at the American Academy of Otolaryngology--Head and Neck Surgery Foundation Annual Meeting/OTO EXPO, being held September 9-12, 2001, at the Colorado Convention Center, Denver, CO.
Methodology: From October, 1999 through April, 2000, all patients 16 and older, scheduled for upper airway surgery, were offered enrollment into the study if they did not have other localized or systemic disease that could have an effect upon speech/voice production (including but not limited to respiratory and neurological disease). Consequently, 44 patients were included, their ages ranging from 19 to 65 years (mean 41). All subjects were tested within one week prior to surgery, and one to three months postoperatively (mean 6.3 weeks). Surgeries performed included UPPP (uvulopalatopharyngoplasty), UPPP with tonsillectomy, UPPP with septoplasty and/or turbinectomy, and sinus surgery. Data from ten healthy subjects was also obtained (mean age 34) on a time schedule similar to the surgical subjects.
Measures included 1st and 2nd formant frequencies (F1, F2) for the non-nasalized and nasalized vowels /a/, /i/, /ae/, /u/, relationship of first formant amplitude to nasal peak amplitude (A1-P1n) and first formant amplitude to low frequency peak amplitude (A1-P0) of nasalized vowels and consonants /m/ and /n/, and Voice Handicap Index score.
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Results: Patients were divided into three surgical groups for analytic purposes: septoplasty + turbinectomy (15 patients), septoplasty + turbinectomy + ancillary procedures (13 patients), septoplasty + turbinectomy + tonsillectomy with or without ancillary procedures (16 patients). No statistically significant differences were found between groups for any measure. For the normal control subjects, there were no significant differences found between the two measurement testing sessions on any of the acoustic measures. Additional findings included:
The mean values for the F1 and F2 frequencies for the vowels /i/, /a/, /ae/, /u/ in non-nasal and nasalized speech contexts were not significantly different before and after surgery. Although there was variability in mean vowel formant within subjects across surgery, in each case the individual variability was not significant.
* The relationship of first formant amplitude to nasal peak amplitude (A1-P1n) for both nasal consonants /m/ and /n/ was significantly increased after surgery (p<.05). The postoperative increase ranged from 9 dB to 17 dB. The mean A1- P1n value for each of the non-nasal vowels was unchanged as a result of surgery. For the nasal vowels, however, the mean postoperative A1- P1n value were significantly increased. The postoperative increase ranged from 8 to 16 dB. Qualitative assessment of the spectra for the nasal consonants and nasalized vowels revealed that, on average, the postoperative increase in A1-P1n values were due to both an increase in A1 and a decrease in P1n. These changes resulted in postoperative A1-P1n values moving closer to the values obtained from the normal controls.
* The mean A1-P0 values (relationship of the first formant amplitude to low frequency peak amplitude) were unchanged for all non-nasalized vowels. However, there was a significant decrease in postoperative mean A1-P0 values for the low nasalized vowels /a/ and /ae/. The decrease for the high vowels (/i/ and /u/) approached significance. The absolute values of the A1-P0 decrease for all vowels ranged from 5 to 10 dB.
* No significant differences between pre- and postoperative mean VHI scores were obtained for all patients. This finding is consistent with the general lack of change in vocal quality as perceived by most patients. When asked whether there was a change in the voice postoperatively, the majority of the patients commented that they did not notice a change, although many subjects reported that friends and relatives noted improved voice. No overall increase or decrease in nasality was consistently noted.
* A total of five patients reported a voice disorder pre- and postoperatively, one in the non-UPPP group and four in the UPPP group. All VHI scores for these five patients decreased postoperatively, but only one of these patients reported no voice disorder postoperatively (from the UPPP group).
Conclusions: The research suggests that upper airway surgery can influence acoustic resonant characteristics. These surgeries may be considered to have a positive influence upon vocal quality, because the postoperative acoustic characteristics are more representative of normative data than the preoperative values.
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