respiratory system speech science

What happens to the diaphragm during quiet breathing? 

Primarily contraction and relaxation of the diaphragm.

What is the rate of rest breathing for adults and its trend? 

• Adults: 12–18 breaths/min 

• Trend: breathing rate decreases with age 

What is the breathing pattern for quiet breathing? 

• 40% inhale / 60% exhale 

• Nose breathing dominates

• Abd moves more than rc because the diaphragm is doing most of the work

What is a spirometer? 

Measures respiratory volumes — how much air you breathe in and out.

What is tidal volume? 

• the amount of air you breathe in and out during one normal breath. 

• Changes with activity; Quiet rest = small TV, Vigorous activity = larger TV

What are the tidal volume values of adult males and the trend for tidal volume?

• Adult male: 600–750 cc

• Trend: TV increases with age 

What is vital capacity (VC)?

• The amount of air you can blow out after taking the biggest breath in. 

• Vital capacity = Inspiratory reserve volume + Expiratory reserve volume + Tidal volume 

What are the vital capacity volumes for young adults and its trend?

• Young adults: 5000–5300 cc

• Trend: VC increases with age, then decreases in older adulthood.

What is inspiratory reserve volume? (IRV) 

Air you can inhale above a normal breath 

What is expiratory reserve volume? (ERV) 

Air you can exhale below a normal breath

What is residual volume? (RV) 

Air that stays in your lungs even after you exhale as much as possible. You cannot push this air out voluntarily. (Adults: 1000–1500 cc)

What is functional residual capacity? (FRC)

ERV + RV – air left in lungs after a normal exhale.

What is total lung capacity? (TLC) 

All the air your lungs can hold (TV+IRV+ERV+RV) 

What is the function of maximum phonation time? (MPT)

• How long you can say /a/ on one deep breath, hold it as long as possible. 

• It roughly estimates respiratory volume, 

• it’s affected by laryngeal function (vocal fold resistance). 

• High laryngeal resistance = artificially longer MPT.

What are the normal MPT values for young males and its trend?

• Young Males: 28 sec (range 22–35)

• Trend: MPT decreases with age.

What is the function of the maximum /s/ duration and values for young adults?

Maximum /s/ duration removes the laryngeal factor. It’s basically a pure respiratory measure. 

• Young adults: 20–30 sec

• Trend: decreases with age.

What are the norms of speech breathing?

• Normal adult speech: uses 20–25% of vital capacity 

• Loud speech: uses about 40% of VC 

• Children: use about 35% of VC (they need more air because their systems are smaller) 

What are breath groups and how do you measure them?

• A breath group = the number of words you say on one breath. 

• How to measure: Read aloud → mark where you inhale → count the words between breaths. 

What is the normal breath group length got adults? 

• Adults: 11–16 words per breath (≈ 16–22 syllables per breath) 

What are the effects of age on syllables per breath?

• 25 yrs: ~20 syllables 

• 50 yrs: ~22 syllables 

• 75 yrs: ~16 syllables 

• Trend: Breath groups get shorter in older adults

What are additional respiratory tasks considered in a respiratory assessment?

• Loudness tasks

• Strong sniffs & gasps

• Strong blows & coughs 

• Rapid panting

• Posture effects

• Slow controlled expiration

What is the framework for evaluating respiratory fuction?

1. Volume  

2. Air Pressure 

3. Airflow  

4. Chest wall shape & movement 

What is air pressure?

• the forces generated by the respiratory process  

• force per unit area  (centimeters of water: cmH2O) 

• reflects the power supply for speech

What are the different speech pressures?

• Palv - alveolar pressure = pressure inside the lungs 

• Ps – subglottal pressure = pressure below the vocal folds 

• Ptrach – tracheal pressure = pressure below the vocal folds and inside the trachea 

• Poral – oral pressure = pressure inside the mouth (intraoral pressure) 

• Pnasal - nasal pressure = pressure inside the nasal cavities

How do we measure speech pressures? 

Direct  Ps/Ptrach measurement = invasive 

Indirect measurement = non‑invasive 

Equal-pressure conditions if;  

• Nose is plugged  

• Vocal folds open  

• Mouth closed  

• oral, subglottal, tracheal, and alveolar pressures all become equal 

measurement of oral pressure during /p/ closure gives a good estimate of subglottal, tracheal, and alveolar pressures

What is a manometer and its function? 

• Manometer = U‑tube or gauge that measures slow, steady pressure 

• Good for static pressure tasks

• 5 cmH₂O for 5 seconds = minimum pressure needed for speech 

• Straw‑in‑water test = easy way to check if someone can hit 5 cmH₂O for 5 sec 

• Not good for fast, dynamic speech pressures

What is an air pressure transducer and its function? 

• Air pressure transducer converts pressure → electrical signal for computer display 

• Tube goes into the mouth 

• Oral pressure during /p/ in running speech ≈ subglottal pressure estimate 

• Conversational speech: 5–10 cmH₂O 

• If loudness stays constant → pressure stays consistent 

• Pressure increases with loudness 

• Doubling pressure → +8–9 dB louder 

What are the maximum effort air pressures for young males, young females, older males, older females and children?

• Young males: 166 cmH₂O 

• Trend: air pressure is smallest in children, increases in young adulthood (men highest) and decreases in older adults.

What are the intraoral air pressure for speech sounds?

• Voiceless plosives (p, t, k): 5–7 cmH₂O 

• Voiced plosives (b, d, g): 3–4 cmH₂O 

• Voiceless fricatives (s, f, ʃ): 4–6 cmH₂O 

• Voiced fricatives (z, v, ʒ): 2–3 cmH₂O 

• Glides/liquids (w, j, l, r): 0.5–1 cmH₂O 

• Nasals (m, n, ŋ): 0.2–0.4 cmH₂O 

What is airflow? 

• change in volume of air over a certain period of time  

• also referred to as volume velocity 

• preferred unit of  measure  ml/sec    (also  ml/min and l/sec) 

What is a rotameter?

• A rotameter has a small ball in a tapered tube. 

• More airflow = ball rises higher. 

• Good for slow, steady (static) airflow. 

• Not good for fast, dynamic speech airflow. 

• Used for simple tasks like checking if someone can maintain airflow.

What is a pneumotachograph? 

• A pneumotachograph measures continuous airflow electronically. 

• Works by measuring pressure difference across a fixed resistance: Flow = (Pressure₁ – Pressure₂) / Resistance 

• Uses a face mask with a small wire mesh of known resistance. 

• Great for dynamic speech airflow (real‑time display on computer). 

What is the average airflow during prolonged vowel /a/ ? (men) 

Most airflow in conversation comes from vowels (they take up most of speaking time). 

• Adults (conversation) = 170 ml/sec

• Men = 112 ml/sec

What is the duration for consonant air flow? 

• Voiceless stops /p t k/: 900 ml/sec 

• Voiced stops /b d g/: 400 ml/sec 

• Voiceless fricatives: 400 ml/sec 

• Voiced fricatives: 100–150 ml/sec 

• Glides/liquids: 100–150 ml/sec 

• Vowels: 100–150 ml/sec 

What is laryngeal resistance? 

• Laryngeal resistance = pressure ÷ airflow (Just like Ohm’s law: Pressure = Flow × Resistance) 

• We estimate it using oral pressure and oral airflow during /pipipipi/. 

How to measure laryngeal resistance?

• Measure peak oral pressure during /p/ (Example: 5 cmH₂O)

• Measure airflow during /i/ (Example: 140 ml/sec = 0.14 L/sec)

• Calculate resistance (Resistance=50.14≈35.7) 

• Normal adult laryngeal resistance ≈ 35 cmH₂O/L/sec

What are the voice quality effects of laryngeal resistance?

Breathy voice: 

• Low resistance (~20) 

• Because airflow is high (~250 ml/sec) 

Strained voice: 

• High resistance (~60) 

• Because airflow is low (~83 ml/s/sec) 

Explain the relation between lung volume and chest wall shape 

Lung volume changes come from two parts of the chest wall: 

• Rib cage movement 

• Abdomen movement 

If you measure how much the rib cage (RC) and abdomen (ABD) expand or shrink, you can accurately tell how much the lungs are filling or emptying.

How do we measure rib cage (RC) and abdomen (ABD) movements? 

Inductive Plethysmography 

• Two coiled wires wrap around RC and ABD 

• The chest/abdomen expand, the coils change electromagnetic inductance 

• Produces a continuous electrical signal showing RC + ABD movement 

Magnetometer 

• Magnetic transmitter + receiver coils placed front + back of RC and ABD 

• Changes in RC/ABD diameter → changes in magnetic force 

• Also gives a continuous (dynamic) electrical signal of movement

What does the chest wall display when we measure rib cage (RC) and abdomen (ABD) movements? 

Shows RC movement (y‑axis) vs ABD movement (x‑axis) Used to see: 

• Start, end, total volumes 

• Movement patterns 

• smooth vs variable 

• parallel vs paradoxical (opposite directions)