1. Airflows for Speech and Voice
Lab 4

2. Airflow Vocal tract= aerodynamic sound generator & resonator
Airflow changes due to vowel & consonant articulation
Evaluation of airflow can provide insight into speech system dysfunction & efficiency
Precision of diagnosis
Documenting change due to therapy
Biofeedback to patients with voice or articulation disorders

3. Airflow
Flow= movement of a gas through a given area in a unit of time.
Units of measurement-
liters or milliliters/sec or per minute
Rate of flow is proportional to pressure
Rate of flow is inversely proportional to the resistance of the structure in which the gas is moving through

4. Air Volume All air for speech comes from the lungs
Air volumes used in speech = Change in lung volume
Important: How much volume does it take to complete a speech task? Compared to total vital capacity?

5. Airflow Instrumentation
Face masks-
All air must be measured
Only air pertaining to speech
Articulation must not be impeded
No leaks around circumference of mask

6. Airflow Instrumentation
Airflow Transducers
Transduce an airflow into an appropriate electrical signal
Pneumotachograph
Pressure drop is measured across a resistance to airflow (wire mesh screen)
Warm wire anemometer

7. Calibration
Flow is calibrated by observing the systems output when known airflows are passed through the transducer
Rotometer (flow meter)
Syringe (1 liter)
Aerophone calibration

8. Laboratory 4
Part I:
Calibrate aerophone F300 flow head if necessary
Measure mean flow (flattest portion of flow waveform)
Normal airflow rates:
= .100 ml/sec; = .120 ml/sec (estimates..remember there is a standard deviation of about .56 ml/sec)

9. Laboratory 4 Part I (Cont.):
Onset of flow = time before initiation of vowel production
Offset= time after vowel production has stopped
Stability of trace-
Hint- look at how much volume has been expended vs. the time for each trace
Oscillating flow trace- measure in the middle of trace for flow value

10. Laboratory 4 Polypoid Airflow Record:
Measure mean airflow at about the middle of the waveform (measure highest and lowest point and estimate middle)
Compare to norms
Remember the relationship: Greater irregularity in the signal, greater noise- Is this signal regular?

11. Laboratory 4 Polypoid Airflow Record (cont.)
Airflow trace should be periodic to mirror glottal opening and closing
More aperiodicity in the flow trace = increased laryngeal inefficiency
MPT (maximum phonation time)=
vital capacity/ flow (L/sec)

12. Laboratory 4 Part II: Sustained phonation airflow
Use Aerophone II- Choose Mamimal Sustainbed phonation task and sustain /a/ for as long as you can.
Cursor in on the beginning of the airflow waveform, mark and then mark at end of the waveform
Measure (calculate data)
Report mean airflow for sample
Now collect the same /a/ , but use a louder voice.
Compare comfortable and louder phonation airflows

13. Laboratory 4 Part II: Use /pa/ task (labeled C)
Label peak pressure & vowels
Frequency response- Should see sharp rise of flow after release of /p/ and oscillation of flow to represent glottal pulsing
Mean peak airflow for the /p/ (not the vowel)

14. Laboratory 4 Part II: Normal subject-(labeled D) “Today is a sale”
Measure peak airflow /t/, /d/, /s/, /z/
Ripples in the flow signal indicate voicing
Articulation of /l/- decrease in flow. Why?
Plosives vs. fricatives- Voicing? Peak strength?
Mean airflow in connected speech? Variable?

15. Laboratory 4 Part II: Dysarthric speaker (labeled E)
What are the differences in this production of “Today is a Sale” Compared to the normal sample
Duration
Flow release of fricatives
Slower or faster?