1,2 s s · 2014. 9. 29. · secondary to hemiparesis1,2. Higher oxygen cost with hemiparetic gait...
Transcript of 1,2 s s · 2014. 9. 29. · secondary to hemiparesis1,2. Higher oxygen cost with hemiparetic gait...
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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
References 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.
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
Author contact Cynthia Otfinowski, MSc candidate. Email: [email protected].
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.
PURPOSE
Reduced depth of breathing and walking speed may occur post-stroke
secondary to hemiparesis1,2.
Higher oxygen cost with hemiparetic gait may result in similar ventilatory
requirements for people with stroke who walk slower than neurologically intact
adults3.
Depth of breathing increases with fast walking in healthy people but it is
unknown if this adaptation occurs post-stroke4.
Understanding the relationship between walking speed and tidal volume may
provide insight into limitations of exercise capacity and community ambulation in
people post-stroke.
RATIONALE
CONCLUSIONS / IMPLICATIONS People post-stroke are able to increase depth of breathing in standing similar
to the control group, suggesting voluntary control of breathing is intact.
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.
Table 1: Demographics and baseline measures of
persons with stroke and controls.
*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.
Figure 2: Lab set-up: A) equipment; B) virtual reality screen viewed by participants.
Outcome measures:
• Gait speed (m/s) (foot markers
captured by VICON MX System)
• Air flow (pneumotachograph)
integrated to obtain tidal volume (L)
A B
Ethics approved by the Centre de recherche interdisciplinaire en réadaptation
du Montréal métropolitain (CRIR).
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.
Figure 5: Tidal volume changes while breathing deeply and increasing walking speed
from comfortable to fast.
While breathing deeply and walking faster, tidal volume
decreased in persons with stroke.
Statistical analysis:
Data for the three conditions (QST, DST, QF) were analyzed for each group
using an one-way repeated measures ANOVA for tidal volume.
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).
METHODS
Gait speed
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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.
Outlier
Chan
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in tid
al vo
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L)
Change in walking speed (m/s)
Figure 4: Change in walking speed when increasing from quiet to deep breathing.
While walking a comfortable pace and breathing deeper,
75% of participants with stroke walked faster.
Stroke
Control
Table 2: Results for tidal volume and walking speed.
Figure 1: Experimental design. Conditions A, B, C, D were randomized according to
a balanced Latin-square design.
2 groups: People with stroke and age- and gender-matched healthy adults.
Each walking trial is 2 minutes long with a 5 minute rest in sitting between trials
Vital capacity is the lung volume between maximum inspiration and expiration.
Tidal volume is the lung volume during a breath cycle.
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.
Contrary to our expectations, people with stroke increased tidal volume
voluntarily in standing from quiet to deep breathing (p<0.001).
Similar to our expectations, tidal volume increased with exercise, when
comparing standing to fast walking while breathing quietly (p<0.05).
People with stroke have lower tidal volumes compared to the control group
while walking fast but similar in standing.
Figure 3: Tidal volume in each condition in people with stroke or the control group.
Tidal volume increases with deep breathing or fast walking
in persons with stroke and the control group.
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VC QST DST QC QF
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Standing
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Breathing
Standing
Vital
Capacity
Standing
3.00
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p<0.001
p=0.040
p=0.025
Outlier
Chan
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Change in walking speed (m/s)
Stroke
Control
Variables Stroke Control
Median (range) (n=) Median (range) (n=)
Age (years) 56 (44-71) 12 54 (41-67) 11
Gender 7 males : 5 females 12 7 males : 4 females 11
Body mass index (kg/m2) 28 (21-30) 12 24 (19-30) 11
Forced expiratory volume in 1 sec
(FEV1) (%)
97 (57-121) 7 104 (87-107) 4*
Forced vital capacity (FVC) (%) 97 (55-129) 7 102 (87-114) 4*
FEV1/FVC (%) 81.3 (75.3-93.9) 7 81.8 (72.9-83.7) 4*
Smoking history (pk*yrs) 10 (0-57) 7 0 (0-45) 6
Current smoker? 1 yes: 6 no 7 1 yes: 5 no 6
International Physical Activity
Questionnaire
1418 (281 - 14536) 7 2172 (660-13311) 6
10 m gait speed (comfortable) m/s 0.61 (0.32-1.30) 12 1.41 (1.12-1.87) 10*
10 m gait speed (fast) m/s 0.81 (0.40-1.73) 12 2.06 (1.75-2.63) 10*
6 minute walk test (m) 330 (106-525) 7 632(483-775) 6
Gait aid 4 none; 8 cane 12 11 none 11
Orthosis 6 none: 4 ankle foot: 2
ankle supporting
12 11 none 11
Paretic side 9 right: 3 left 12 n/a -
Time since stroke (months) 27 (8-200) 12 n/a -
Chedoke-McMaster Stroke Assessment
(leg/ foot)
(3-6) leg; (2-5) foot 7 n/a -
Variable Subject Quiet
Breathing
Comfortable
Walking
Deep
Breathing
Comfortable
Walking
Quiet
Breathing
Fast
Walking
Deep
Breathing
Fast
Walking
Tidal volume (L) Stroke 0.922 (0.259) 1.539 (1.180) 0.954 (0.249) 1.181 (0.924)
Tidal volume (L) Control 1.012 (0.239) 2.08 (0.573) 1.228 (0.324) 2.164 (0.569)
Gait speed (m/s) Stroke 0.40 (0.23) 0.48 (0.22) 0.51 (0.30) 0.59 (0.33)
Gait speed (m/s) Control 1.00 (0.28) 1.12 (0.31) 1.53 (0.14) 1.58 (0.21)