Topic 3c: Respiration
1
Learning Objectives
• Posses a knowledge of respiratory anatomy sufficient to understand
basic respiratory physiology and its relation to speech sound
generation.
• Describe how physical laws help explain how air is moved in and out
of the body
• Outline the functional subdivisions of the lung volume space
• Compare and contrast characteristics of speech breathing and
metabolic/vegetative breathing
• Use the pressure-relaxation curve to explain the active and passive
forces involved in controlling the respiratory system
• Describe how various respiratory impairments can lead to
diminished speech production abilities
2
Learning Objectives
• Posses a knowledge of respiratory
anatomy sufficient to understand basic
respiratory physiology and its relation to
speech sound generation.
3
Speech Breathing
• Why do we breathe?
• How does breathing help us speak?
4
Life and Speech Breathing
ARE DISTINCT PROCESSES in terms
of
• Primary functional goal
• Surface features
• Mechanisms underlying action
5
Role of breathing in speech
• Respiratory System is a Variable Power
Source
• Aerodynamic power needed to generate
sound sources
– Phonation, frication, bursts, aspiration
• Must be able to vary power to allow for
– Intensity variation (phonation & obstruent
production)
– Fundamental frequency variation
• Must also meet metabolic needs of speaker
6
Structure and Mechanics of Respiratory
System
• Pulmonary system
– Lungs and airways
• Upper respiratory system
• Lower respiratory system
• Chest wall system
– “Houses” pulmonary system
– Structures on which muscle activity is generated
• Pulmonary system & chest wall are linked
(pleural linkage)
7
Pulmonary system: lower respiratory tract
8
Pulmonary system: lower respiratory tract
9
Chest wall system
• Rib cage
• Abdomen
• Diaphragm
10
Chest wall-Lung relation
•
•
•
•
•
Lungs not physically attached to the thoracic walls
Lungs: visceral pleura
Thoracic wall: parietal pleura
Filled with Pleural fluid
Ppleural < Patm - “pleural linkage” allows the lungs to move
with the thoracic wall
• Breaking pleural linkage Ppleural = Patm - pneumothorax
11
Thorax
12
Abdomen
13
Diaphragm
14
Learning Objectives
• Describe how physical laws help explain
how air is moved in and out of the body
15
Physics of Breathing
Key Quantities
• Pressure (P)
• Volume (V)
• Flow (U)
Boyle’s Law
• V=k/P or V P=k
• As V ↑ P↓
• As V ↓ P ↑
16
Flow (U)
A
B
17
Moving air within respiratory
system
Patm: atmospheric pressure
Palv: alveolar pressure*
Vthoracic : thoracic volume
P = k/V: Boyle’s Law
 Vthoracic =  Palv
 Vthoracic =  Palv
Palv < Patm
(- Palv)
P differential = density differential 
air molecules flowing into lungs =
inspiration
Palv > Patmos
(+ Palv)
P differential = density differential
 air molecules flow out of
lungs = expiration
*pressure in lungs typically described as alveolar pressure
18
Changing thoracic volume (Vthoracic):
two degree of freedom model
Requires
• Muscular forces
• Elastic forces
Strategies
• ∆ Length
• ∆ Circumference
19
Changing length of thoracic
cavity
Diaphragm
Abdominal wall
muscles
20
Changing circumference of thoracic
cavity
Rib cage elevation
(e.g. external intercostals m.)
Rib cage lowering
(e.g. internal intercostals m.)
21
Summary: Changing lung volume (
Vlung)
• pleural linkage:  Vthoracic =  Vlung
•  Vthoracic is
– raising/lowering the ribs (circumference)
• Raising:  Vthoracic = inspiration
• Lowering:  Vthoracic =expiration
– Raising/lowering the diaphragm (vertical dimension)
• Raising: Vthoracic =expiration
• Lowering:  Vthoracic =inspiration
22
Learning Objectives
• Outline the functional subdivisions of the
lung volume space
23
Lung Volume
Measuring Lung Volume:
Spirometry
24
Lung Volume
Measuring Lung Volume:
Spirometry
Time
25
Selected volumes, capacities and
levels
Tidal Volume (TV)
– Volume of air inspired/expired during rest breathing.
Expiratory Reserve Volume (ERV)
– Volume of air that can be forcefully exhaled, “below” tidal volume.
Inspiratory Reserve Volume (IRV)
– Volume of air that can be inhaled, “above” tidal volume.
Vital Capacity (VC)
– Volume of air that can be inhaled/exhaled (i.e. VC=IRV +TV+ERV)
Residual Volume (RV)
– Volume of air left after maximal expiration. Measurable, but not easily so.
Total Lung Capacity (TLC)
– Volume of air enclosed in the respiratory system (i.e. TLC=RV+ERV+TV+IRV)
Resting End Expiratory Level (REL)
– Location in lung volume space where tidal breathing typically ends (35-40 % VC in
upright position)
26
NOTE
• Some authors use the term FRC
(functional residual capacity) instead of
REL (resting end-expiratory level)
• Behrman uses resting lung volume (RLV)
• Refers to equivalent “place” in the lung
volume space
27
Some typical adult values
Typical Volumes & Capacities
Typical Rest Breathing Values
Vital Capacity (VC)
4-5 liters
Respiratory rate
12-15 breaths/minute
Total Lung Capacity (TLC)
~ one liter more than VC
Alveolar Pressure Palv
+/- 2 cm H20
Resting Tidal Volume (TV)
~ 10 % VC
Airflow
~ 200 ml/sec
Resting expiratory end level
(REL)
~ 35-40% VC when upright
28
Learning Objectives
• Compare and contrast characteristics of
speech breathing and
metabolic/vegetative breathing
29
30
Speech vs. Life Breathing
Rest Breathing
Speech Breathing
Volume
10 % VC at rest
Volume
20-25 % VC @ normal loudness
(note this varies by utterance
length)
40 % loud speech
Alveolar Pressure Palv
+ 8-10 cm H20 on expiration
Alveolar Pressure Palv
+/- 2 cm H20
Average Airflow
100-200 ml/sec
Ratio of inhalation to
exhalation
~40/60 to 50/50
Average Airflow
100-200 ml/sec
Ratio of inhalation to exhalation
~ 10/90
31
Respiratory System Mechanics
• It is spring-like (elastic)
• Elastic systems have an equilibrium point
(rest position)
• What happens when you displace it from
equilibrium?
32
Learning Objectives
• Use the pressure-relaxation curve to
explain the active and passive forces
involved in controlling the respiratory
system
33
Displacement away from equilibrium
Restoring force back to equilibrium
equilibrium
Longer than
equilibrium
34
Displacement away from equilibrium
Restoring force back to equilibrium
Shorter than
equilibrium
equilibrium
35
Displacement away from equilibrium
Restoring force back to equilibrium
Shorter than
equilibrium
equilibrium
Longer than
equilibrium
36
Displacement away from REL
Restoring force back to REL
Lung Volume
Below REL
REL
Lung Volume
Above REL
37
Is the respiratory system heavily or
lightly damped?
38
Respiratory Mechanics: Bellow’s Analogy
• Bellows volume = lung volume
• Handles = respiratory muscles
• Spring = elasticity of the respiratory system
39
REL: Respiratory System
Equilibrium
• No pushing or pulling on the handles ~ no exp. or insp.
muscle activity
• Volume in bellows at rest ~ REL
• Patmos = Palv, therefore no airflow
40
Shifting Lung Volume away from
REL
muscle force
elastic force




pull handles outward from rest
V increases ~ Palv decreases
Inward air flow
INSPIRATION
muscle force
41
Shifting Lung Volume away from
REL
muscle force
elastic force




push handles inward from rest
V decreases ~ Palv increases
outward air flow
EXPIRATION
muscle force
42
Respiratory Mechanics: Bellow’s Analogy
Forces acting on the bellows/lungs are due to
•
Elastic properties of the system
–
Passive
–
Always present
•
Muscle activity
–
Active
–
Under nervous system control (automatic or voluntary)
•
Moving to a volume other than REL requires an external force
–
Muscle activity (inspiratory or expiratory)
–
Mechanical assistance (mechanical ventilator)
43
Characteristics of System Elasticity
•
•
•
•
Since elastic recoil forces will have the effect of
exerting a pressure within the respiratory system,
the effect is termed the relaxation pressure
Magnitude of relaxation pressure is roughly
proportionate to the amount of displacement from
REL
REL is expressed as a lung volume
This gives rise to a relaxation pressure curve
–
Plots relaxation pressure (units Palv) as a function of
lung volume
44
Relaxation Pressure Curve
(as in Behrman)
45
Relaxation Pressure Curve
(Our version)
46
Alveolar Pressure (cm H20)
60
40
20
REL
0
-20
-40
-60
100
80
60
40
20
0
% Vital Capacity
47
Breathing for Life: Inspiration

pulling handles outward with net
inspiratory muscle activity
48
Breathing for Life: Expiration


No muscle activity
Recoil forces alone returns
volume to REL
49
Breathing for Life
Alveolar Pressure (cm H20)
60
40
20
0
~ 2 cm
-20
-40
-60
100
10 %
80
60
40
% Vital Capacity
20
0
50
Respiratory demands of speech
• Conversational speech requires
– Constant average alveolar pressure
• Generate subglottal and supraglottal pressures for sound
production
– Ability to generate quick variations in pressure
• Vary intensity
• Vary fundamental frequency
• For emphatic and syllabic stress, phonetic requirements etc
– Requires a respiration system OPTIMIZED for action
51
Respiratory demands of speech
• Conversational
speech
– Volume solution
• Constant alveolar
pressure 8-10 cm H20
– Pulsatile solution
• Brief increases
above/below constant
alveolar pressure
• Driving analogy
– Volume solution
• Maintain a relatively
constant speed
– Pulsatile solution
• Brief
increases/decreases in
speed due to moment
to moment traffic
conditions
52
Pressure wrt atmosphere
Example
10
5
0
-5
Time
53
Breathing for Speech: Inspiration


pulling handles outward with net
inspiratory muscle activity
Rate of volume change is greater than
rest breathing
54
Breathing for Speech
Alveolar Pressure (cm H20)
60
40
20
0
Target Palv ~ 8-10 cm
-20
-40
-60
100
20 %
80
60
40
% Vital Capacity
20
0
55
Breathing for Speech: Expiration
Expiratory muscle activity & recoil
forces returns volume to REL
 Pressure is net effect of expiratory
muscles (assisting) and recoil forces
(assisting)

56
60
Optimal region
Prelax > 0
assists Palv
Alveolar Pressure (cm H20)
40
Add Pexp to
Meet Palv
20
0
Target Palv ~ 8-10 cm
-20
-40
-60
100
20 % VC
change
80
60
40
% Vital Capacity
Prelax: relaxation pressure
Psg: target alveolar pressure
Pexp: net expiratory muscle pressure
Pinsp: net inspiratory muscle pressure
20
0
57
60
Prelax > Palv
Alveolar Pressure (cm H20)
40
Requires
“braking”
Add Pinsp to
Meet Palv
Optimal region
Prelax > 0
assists Palv
Below REL
Prelax < 0
opposes Palv
Add Pexp to
Meet Psg
Add Pexp to
meet Palv
& overcome
20
0
Prelax
Target Palv ~ 8-10 cm
-20
-40
-60
100
20 % VC
change
80
60
40
% Vital Capacity
Prelax: relaxation pressure
Palv: target alveolar pressure
Pexp: net expiratory muscle pressure
Pinsp: net inspiratory muscle pressure
20
0
58
Speech Breathing is VERY ACTIVE
• Modern view of speech breathing (Hixon
et al. (1973, 1976)
59
Summary: Muscle activity
Inspiration
Life
•
Active inspiratory muscles
–
Principally diaphragm
Speech
•
COACTIVATION OF
–
inspiratory muscles
•
•
–
•
•
Diaphragm
Rib cage elevators
expiratory muscles
(specifically abdominal)
INS > EXP = net inspiration
System ‘tuned’ for quick
inhalation
Expiration
Life
• Relaxation pressure
• No muscle activity
Speech
• Active use of
– rib cage depressors
– abdominal muscles
• System “Tuned” for quick brief
changes in pressure to meet
linguistic demands of speech
60
Summary: Muscle activity
No Airflow
Life
• Minimal muscle
activity
Speech
• COACTIVATION of
–
–
–
Inspiratory: rib cage
Expiratory: abdomen
System ‘balanced’
61
Interpretation of information
• Constant muscle activity may serve to “optimize”
the system in various ways
For example,
• Abdominal activity during inspiration
• pushes on, and stretches the diaphragm
• Optimal length-tension region of diaphragm
• Increase ability for rapid contraction which is
needed for speech breathing
62
Interpretation of information
• Constant muscle activity may serve to “optimize”
the system in various ways
For example,
• Abdominal activity during expiration
• Provides a platform for rapid changes in ribcage
volume (pulsatile)
• Without constant activity, abdomen would
‘absorb’ the forces produced by the ribcage
63
Learning Objectives
• Describe how various respiratory
impairments can lead to diminished
speech production abilities
64
Chest Wall Paralysis
• Remember those spinal nerves…
• Paralysis of many muscles of respiration
Speech breathing features
• variable depending on specific damage
•  abdominal size during speech
•  control during expiration resulting in difficulty
generating consistent Palv and modulating Palv
• Treatment: Support the abdomen
65
Mechanical Ventilation
• Breaths are provided by a machine
Speech breathing features
•  control over all aspects of breath support
• Length of inspiratory/expiratory phase
• Large, but inconsistent Palv
• Inspiration at linguistically inappropriate places
• Speech breathing often occurs on inspiration
• Treatment: “speaking valves”, ventilator
adjustment, behavioral training
66
Parkinson’s Disease (PD)
• Rigidity, hypo (small) & brady (slow) kinesia
Speech breathing features
•  muscular rigidity   stiffness of rib cage
•  abdominal involvement relative to rib cage
•  ability to generate Palv
• modulation Palv
• Speech is soft and monotonous
67
Cerebellar Disease
• dyscoordination, inappropriate scaling and
timing of movements
Speech breathing features
• Chest wall movements w/o changes in LV
(paradoxical movements)
•  fine control of Palv
• Abnormal start and end LV (below REL)
• speech has a robotic quality
68
Other disorders that may affect
speech breathing
•
•
•
•
Voice disorders
Hearing impairment
Fluency disorders
Motoneuron disease (ALS)
69
Lifespan considerations (Kent, 1997)
• Respiratory volumes and capacities
–  until young adulthood
–  young adulthood to middle age
–  during old age
•  stature
•  elastic properties
•  muscle mass
70
Lifespan considerations (Kent, 1997)
• Maximum Phonation Time (MPT)
– Longest time you can sustain a vowel
– Function of
• Air volume
• Efficiency of laryngeal valving
– Follows a similar pattern to respiratory volume
and capacities
71
Lifespan considerations (Kent, 1997)
• Birth
– Respiration rate 30-80 breaths/minute
– Evidence of ‘paradoxing’
– Limited number of alveoli for oxygen
exchange
72
Lifespan considerations (Kent, 1997)
• 3 years
– Respiration rate 20-30 breaths/minute
– Speech breathing characteristics developing
73
Lifespan considerations (Kent, 1997)
• 7 years
– Adult-like patterns
– > subglottal pressure than adults
– Number of alveoli reaching adult value of 300,000
• 10 years
– Functional maturation achieved
• 12-18 years
– Increases in lung capacities and volume
74