Airflows for Speech and Voice Lab 4

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

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

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?

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

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

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

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)

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

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?

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)

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

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)

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?

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?