ABSTRACT
Impact stress (IS) has been regarded as the main loading factor in voice production. To quantify the cost of voice production, an output-cost ratio (OCR) was proposed, which concerns acoustic output (pressure P) in relation to IS: OCR = 20 log P(sup)/P(0) - 20 log IS/IS(0) [1,2]. IS is difficult to measure directly in humans. However, it has been found to correlate with closed quotient (CQ, closed time/period length) measured by electroglottogram (CQ(EGG)) [3]. The present study proposes a noninvasive estimate of OCR, the quasi-output-cost ratio (QOCR): (sound pressure level (SPL)/CQ(EGG)) x (period length (T)/T(0)). T(0) is set at 0.005 for females and 0.01 for males, corresponding to the respective period lengths of the mean F(0) in female and male speech (i.e. 200 and 100 Hz). QOCR was tested for 62 healthy females (23 teachers, 18 university students with voice training and 21 without). The teachers had a higher QOCR than the students in loud speech, but QOCR did not correlate with symptoms of vocal fatigue after a vocal loading test. QOCR seems to be a promising tool to quantify vocal loading but naturally not vocal loadedness.
Subject(s)
Electrodiagnosis/methods , Glottis/physiology , Models, Biological , Voice/physiology , Acoustics , Adult , Faculty , Female , Humans , Male , Pressure , Sex Characteristics , Speech/physiology , Speech Acoustics , Stress, Mechanical , Time Factors , Voice Disorders , Voice Quality , Voice TrainingABSTRACT
This article summarizes the results for a total of 189 female and 63 male university students (mean age 23 and 26 years, respectively) from the following vocal capacity tests: measurement of (1) vital capacity, (2) average airflow in phonation (on [o:]), (3) maximum duration of sustained blowing, (4) maximum phonation time (on [o:, z:]), (5) maximum duration of [s:], (6) the ratio of the duration of [s:] to [z:] (s/z ratio), (7) phonation quotient (the ratio between vital capacity and maximum phonation time), (8) the lowest possible tone, (9) mean fundamental frequency (F0) in normal and loud text reading and in shouting, (10) difference between the lowest tone and mean F0 in text reading and in shouting, (11) F0 range in text reading, (12) equivalent sound level of normal and loud reading and of shouting in maximum loudness, (13) phonetogram (voice range profile) and (14) long-term average spectrum of text reading. Voice quality is also evaluated perceptually, and additionally, data on subjects' self-reported vocal fatigue symptoms in general or after a vocally loading task were collected. The value of these measurements from the point of view of assessment of vocal capacity will be discussed.
Subject(s)
Phonation/physiology , Voice Quality , Adult , Female , Finland , Humans , Male , Music , Pulmonary Ventilation , Reading , Vital Capacity , Voice Disorders/physiopathologyABSTRACT
This study investigates the amount of voice training received by teachers in Finland and compares the incidence of vocal symptoms among teachers with shorter, longer or no vocal education. Participating were 124 primary, secondary and upper secondary school teachers; 63% of the teachers had received no vocal training, 15% had received short-term and 22% longer-term training. The incidence of symptoms was lowest in teachers with long-term training and highest in teachers with short-term training. The differences were non-significant among all teachers and females, but significant among males. Speech training seems to protect male teachers from vocal problems better than female teachers. Short-term training may lead to increased awareness of vocal symptoms, which can be helpful in voice protection.
