CPA poster 2014 Depth of breathing and walking speed

Cynthia Otfinowski1, Joyce Fung1,2, Jadranka Spahija1,2,3
1. School of Physical and Occupational Therapy, McGill University; 2. Feil/Oberfeld/CRIR Research Centre, Jewish Rehabilitation Hospital;
3. Research Center, Hôpital du Sacré-Coeur de Montréal.
Montreal (Quebec) Canada
RESULTS
 Reduced depth of breathing and walking speed may occur post-stroke
secondary to hemiparesis1,2.
 Understanding the relationship between walking speed and tidal volume may
provide insight into limitations of exercise capacity and community ambulation in
people post-stroke.
PURPOSE
 To evaluate how increased walking speed impacts the depth of breathing (tidal
volume) in healthy and individuals with stroke and the effect of deep breathing
on walking speed.
METHODS
2 groups: People with stroke and age- and gender-matched healthy adults.
2.0
Variables
Stroke
Control
Median (range)
(n=)
Median (range)
(n=)
Age (years)
Gender
Body mass index (kg/m2)
Forced expiratory volume in 1 sec
(FEV1) (%)
56 (44-71)
7 males : 5 females
28 (21-30)
97 (57-121)
12
12
12
7
54 (41-67)
7 males : 4 females
24 (19-30)
104 (87-107)
11
11
11
4*
Forced vital capacity (FVC) (%)
FEV1/FVC (%)
Smoking history (pk*yrs)
Current smoker?
International Physical Activity
Questionnaire
97 (55-129)
81.3 (75.3-93.9)
10 (0-57)
1 yes: 6 no
1418 (281 - 14536)
7
7
7
7
7
102 (87-114)
81.8 (72.9-83.7)
0 (0-45)
1 yes: 5 no
2172 (660-13311)
4*
4*
6
6
6
0.61 (0.32-1.30)
0.81 (0.40-1.73)
330 (106-525)
4 none; 8 cane
6 none: 4 ankle foot: 2
ankle supporting
12
12
7
12
12
1.41 (1.12-1.87)
2.06 (1.75-2.63)
632(483-775)
11 none
11 none
10*
10*
6
11
11
9 right: 3 left
27 (8-200)
(3-6) leg; (2-5) foot
12
12
7
10 m gait speed (comfortable) m/s
10 m gait speed (fast) m/s
6 minute walk test (m)
Gait aid
Orthosis
Paretic side
Time since stroke (months)
Chedoke-McMaster Stroke Assessment
(leg/ foot)
n/a
n/a
n/a
-
Stroke
Control
Gait speed
1.5
Outlier
1.0
0.5
0.100 L
0.0
-0.5
-0.4
-0.2
-0.100 L
0.05 m/s
 Depth of breathing increases with fast walking in healthy people but it is
unknown if this adaptation occurs post-stroke4.
While walking a comfortable pace and breathing deeper,
75% of participants with stroke walked faster.
-0.05 m/s
 Higher oxygen cost with hemiparetic gait may result in similar ventilatory
requirements for people with stroke who walk slower than neurologically intact
adults3.
Table 1: Demographics and baseline measures of
persons with stroke and controls.
Change in tidal volume (L)
RATIONALE
0.0
0.2
0.4
0.6
0.8
1.0
Change in walking speed (m/s)
Figure 4: Change in walking speed when increasing from quiet to deep breathing.
 Increasing depth of breathing had a significant effect (p=0.040, ANOVA;
p=0.016; post-hoc contrast) on increasing comfortable walking speed in people
with stroke when the outlier was removed.
 With the removal of the two outliers in the control group, the main effect for
breathing is significant (p=0.020) but not while walking a comfortable pace.
*Missing data for 10 m walking tests and pulmonary function tests were due to either machine
malfunction or scheduling issues. Some assessments were not made on the initial participants in
each group (n=5) during pilot testing.
Each walking trial is 2 minutes long with a 5 minute rest in sitting between trials
Figure 1: Experimental design. Conditions A, B, C, D were randomized according to
a balanced Latin-square design.
 Vital capacity is the lung volume between maximum inspiration and expiration.
Tidal volume is the lung volume during a breath cycle.
Tidal volume (L)
Tidal volume (L)
Gait speed (m/s)
Gait speed (m/s)
Stroke
Control
Stroke
Control
Quiet
Deep
Quiet
Deep
Breathing
Breathing Breathing
Breathing
Comfortable Comfortable
Fast
Fast
Walking
Walking
Walking
Walking
0.922 (0.259) 1.539 (1.180) 0.954 (0.249) 1.181 (0.924)
1.012 (0.239) 2.08 (0.573) 1.228 (0.324) 2.164 (0.569)
0.40 (0.23) 0.48 (0.22) 0.51 (0.30) 0.59 (0.33)
1.00 (0.28) 1.12 (0.31) 1.53 (0.14) 1.58 (0.21)
1.0
0.5
0.100 L
0.0
-0.100 L
-0.5
-1.0
-0.4
Figure 2: Lab set-up: A) equipment; B) virtual reality screen viewed by participants.
 Ethics approved by the Centre de recherche interdisciplinaire en réadaptation
du Montréal métropolitain (CRIR).
Tidal volume increases with deep breathing or fast walking
in persons with stroke and the control group.
4.00
3.50
4.000
p=0.040
3.500
Tidal volume (L)
Outcome measures:
• Gait speed (m/s) (foot markers
captured by VICON MX System)
• Air flow (pneumotachograph)
integrated to obtain tidal volume (L)
p<0.001
3.00
3.000
2.50
2.00
1.50
2.500
p=0.025
Outlier
-0.2
0.05 m/s
B
Subject
Stroke
Control
-0.05 m/s
Table 2: Results for tidal volume and walking speed.
Change in tidal volume (L)
1.5
Variable
A
While breathing deeply and walking faster, tidal volume
decreased in persons with stroke.
0.0
0.2
0.4
0.6
0.8
1.0
Change in walking speed (m/s)
Figure 5: Tidal volume changes while breathing deeply and increasing walking speed
from comfortable to fast.
 An interaction between breathing and walking was significant for persons with
stroke (p=0.02 ANOVA).
 Fast (compared to comfortable) pace walking while deep breathing decreased
tidal volume by 8% (p=0.003 post-hoc) in people with stroke.
2.000
1.500
CONCLUSIONS / IMPLICATIONS
1.00
1.000
 People post-stroke are able to increase depth of breathing in standing similar
to the control group, suggesting voluntary control of breathing is intact.
0.50
0.500
0.00
0.000
Off-line data analysis:
 Signals obtained from the pneumotach and VICON Nexus software were
processed using a customized script written in C++, to provide gait speed and
tidal volume data per breathing and walking cycle. These data were averaged
for each individual in each condition.
 The average tidal volume and gait speed for each individual was used for
statistical analysis.
VC
Vital
Capacity
Standing
QST
Quiet
Breathing
Standing
DST
Deep
Breathing
Standing
QC
Quiet
Breathing
Comfortable
Walking
QF
Quiet
Breathing
Fast
Walking
Figure 3: Tidal volume in each condition in people with stroke or the control group.
 Contrary to our expectations, people with stroke increased tidal volume
voluntarily in standing from quiet to deep breathing (p<0.001).
Statistical analysis:
 Similar to our expectations, tidal volume increased with exercise, when
comparing standing to fast walking while breathing quietly (p<0.05).
 Data for the three conditions (QST, DST, QF) were analyzed for each group
using an one-way repeated measures ANOVA for tidal volume.
 People with stroke have lower tidal volumes compared to the control group
while walking fast but similar in standing.
 Data for the four walking conditions (QC, DC, QF, DF) in each group (stroke,
control), were analyzed using two-way repeated measures ANOVA for each
outcome measure (tidal volume and walking speed). Data was transformed
(except tidal volume for people post-stroke) to meet normality criteria.
 Rank sum test was used to compare groups (stroke, control).
 Attempting to increase walking speed while breathing deeply results in a
decrease in tidal volume in persons with stroke, suggesting the respiratory
muscles might prioritize postural stability more than depth of breathing while
walking fast.
 Walking at a comfortable pace and deep breathing may be beneficial for
people post-stroke to optimize tidal volume and walking speed.
Acknowledgements
Staff at JRH: Claire Perez, Valeri Goussev, Christian Beaudoin, Igor Sorokin, Gevorg Chilingaryan
Assistance with data collection: Natalie Levtova, Karan Dev, Semra Orguz, Patrick Smallhorn,
Natalie Diez d’Aux, Feng Shang He, Lyonciny Li, Yu Ren, Anuja Darekar.
Participant recruitment: Jewish Rehabilitation Hospital, Cummings Centre
Institutional support: Jewish Rehabilitation Hospital, CRIR, McGill University
References
Author contact
Cynthia Otfinowski, MSc candidate. Email: [email protected].
1. Lanini B, et al. (2003). Chest wall kinematics in patients with hemiplegia. American Journal of Respiratory and
Critical Care Medicine, 168:109-13.
2. MacKay-Lyons et al. (2006). Cardiovascular fitness and adaptations to aerobic training after stroke. Physiotherapy
Canada, 58(2):103-13.
3. Teixeira da Cunha-Filho I, et al. (2003). Differential responses to measures of gait performance among healthy
and neurologically impaired individuals. Arch Phys Med Rehabil 84:1774-9.
4. Mercier J, et al. (1994). Energy expenditure and cardiorespiratory responses at the transition between walking
and running. Eur J Appl Physiol, 69:525-9.

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