Male Cheerleaders and their Voices

Background Information:What Vocal Folds Look Like

Males vs. Females

Males:

• More Mass• Longer

• More tension

Females:

• Less mass• Shorter

• Less tension• Research reveals

cheering can lead to vocal disorders

MethodsParticipants: INCLUSION MATERIALS: 1. The subject must be a male.2. The male must be a Penn State University Varsity Cheerleader.3. Because acoustic variables are measured pre and post event, additional inclusion criteria, such as number of years of cheerleading or

other demographic characteristics, are not critical for this study. EXCLUSION MATERIALS: 1. The subject cannot be a female2. The participant must be a Penn State Varsity Cheerleader3. The participant must be free of respiratory diseases4. The participant must be free of histamine medication. Equipment: Laptop with sound cardMicrophonePraatExcel

ProcedureThe participants will be involved in two sessions of ten minutes each maximum. Because the

recording session consists only of a recording of the prolonged vowel /a/, the time needed is more than adequate.

1. The male cheerleaders from the Pennsylvania State University will be recorded before

and after a cheerleading event of at least an hours duration. 2. The recordings will take place in a locker room in the BJC 3. The participant will be seated upright in a chair, in the room. 4. A head-mounted microphone will be positioned on the subjects before the recording is

made such that the microphone is at the corner of the participant's mouth at a distance of half an inch. This positioning has been found in previous studies to be more than adequate for the recordings that will be made.

5. The participant will be instructed to take a deep breath and to produce the vowel /a/ (as in father) at a comfortable pitch and loudness for as long as he can.

6. The output of the microphone will be connected to a laptop computer, which will record the signal for later analysis.

7. The identical procedures will be followed both before and after the event.

What Praat Looks Like:

Results• 6 statistical tests performed

1. Fundamental Frequency2. Intensity3. Mean Autocorrelation4. Noise to Harmonics5. Period Perturbation (Jitter)6. Amplitude Perturbation (Shimmer

• The significance level I want to test at is .05. Because there are 6 tests, the new level of significance is .008 (.05/6).– After performing the “t-test” via Microsoft Excel, the tests that reveal statistical

significance are those whose result is less than .008.– If greater than .008, there is no statistical significance found

Fundamental Frequency: Mass of the Vocal Folds:

• The mass of the vocal folds– Mass is higher after compared to before:

• Swelling, edema, caused by trauma (cheering)

** Statistically Significant: Mass increased for the males

Implications:• The vocal folds are trying to compensate the trauma by

increasing tension of the vocal folds and increasing the mass• Swelling also causes the mass to increase• Over-adjusting to sound normal

Intensity: air pressure under the vocal folds

• Is the pressure built up beneath the vocal folds

• The ability to empower the vocal folds by pressure of air to open and close

• Should not change before and after an event

** No statistical significance = no change before and after a cheering event

Mean Autocorrelation

• Measures the strength of voicing– Ex: whether the voice is normal, breathy, or hoarse

• Breathy: too much air, not enough noise• Hoarse: too much extra noise

• Measured by looking at the period of time in a waveform– The more periodic the voice, the better the correlation

• The higher the mean, the more normal the voice• The lower the mean, the less normal the voice

** Not statistically significant = high autocorrelation = normal voicing

Noise to Harmonics Ratio

• Think noise to energy

• Higher harmonics= closer to normal, lots of harmonic energy • Less harmonics = more breathy or hoarse the voice• Because vocal folds are making complete glottal closure,

should be no wasted air– (possible edema, but only affecting fundamental frequency –

greater mass)

**Not statistically significant, higher harmonics = closer to normal voices

Period Perturbation (Jitter)

• Small changes in periodicity from cycle to cycle

• Vocal folds are human tissue, so each cycle will not be exactly the same ( we are not machines) but everyone typically has <1% difference

• ** Not statistically significant = did not change pre vs. post

This is an example of the periodicity being off. In a normal voice recording, the top and bottom pictures would be

the same.

Amplitude Perturbation (Shimmer)• Again, vocal folds are human

tissue, not machines, so there will be some differences in amplitude of the energy, but <5% is normal

• Some may put extra effort after the game to sound natural

** Not statistically significant = magnitude/loudness of sound did not change from cycle to cycle pre vs. post testing

This is an example of different energies in amplitude. In normal speech, the lines would be the same, there would not be a difference.

What all that means:

• From the evidence, I can infer that shouting can cause the vocal folds to swell (causing an edema).– The greater force of yelling causing the vocal folds to collide

more forcefully.• No acoustical evidence that there is hoarseness or

breathiness in males.• Jensen (1964) found that 12% females displayed

hoarseness, I have found 0%.• Can infer that this is because the male vocal mechanism

is larger overall and can withstand more force than females.