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Rhythmic auditory stimulation increases 6-Minute walk distance in individuals with COPD: A repeated measures study
ARTICLE IN PRESS Heart & Lung 000 (2020) 1 5
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Rhythmic auditory stimulation increases 6-Minute walk distance in individuals with COPD: A repeated measures study Alison Hernandeza,b,*, Ulf G. Bronasb, Alana D. Steffenb, David X. Marquezc, Cynthia Fritschib, Lauretta T. Quinnb, Eileen G. Collinsb,d a
Northwestern University, Feinberg School of Medicine, Center for Education in Health Science and Outcomes Research, 633 N St. Clair, 20th Floor (2024-J), Chicago, IL 60611 University of Illinois at Chicago, College of Nursing, 845 South Damen Ave, Chicago IL 60612 c University of Illinois at Chicago, Department of Kinesiology and Nutrition, 1919 W. Taylor, Chicago IL 60612 d Edward Hines Jr., VA Hospital b
A R T I C L E
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Article History: Received 5 September 2019 Revised 20 January 2020 Accepted 22 January 2020 Available online xxx Keywords: COPD Exercise Music 6-minute walk test Rhythmic auditory stimulation
A B S T R A C T
Objective: To evaluate if there is an increase in 6-minute walk distance in individuals with chronic obstructive pulmonary disease (COPD) while walking to rhythmically enhanced music. Background: Individuals with COPD are less active. Walking with rhythmically enhanced music may help Participant’s walk farther while simultaneously distracting from symptoms of dyspnea. Methods: Twenty-five men (age = 70.7 § 4.5 yr), with moderate-to-severe COPD (FEV1 = 47.4 § 9.7% predicted) completed three, 6 min walk tests (6MWT) in random order. Walks were completed with music, with music that was rhythmically enhanced, or without music. Walking distance and perceived dyspnea were measured. Results: Participant’s walked 12 m, 95% CI [20.5-, 2.6], p = 0.015 further during the 6MWT when listening to rhythmically enhanced music when compared to no music. Onset of dyspnea was not different between the three walking conditions. Conclusions: Rhythmically-enhanced music may be a useful tool to increase walking distance in Participant’s with COPD. © 2020 Elsevier Inc. All rights reserved.
Introduction More than 14.5 million individuals are living with chronic obstructive pulmonary disease (COPD), which is the third cause of death worldwide.1,2 Individuals with COPD have reduced exercise tolerance and experience symptoms of dyspnea.3 6 Interventions to enhance exercise tolerance and minimize the perception of dyspnea are important. Listening to music can distract from the perception of dyspnea;7,8 and enhance arousal by priming the body for motor behaviors such as walking.9 Additionally, listening to rhythmic music with an upbeat tempo may increase walking speed in young adult men and women.10 Rhythmic auditory stimulation (RAS) is the process of using music with rhythm and tempo enhancement (i.e. increasing bass and tempo) to entrain the body for movement.11 The rhythm and tempo of music prime the central nervous system (CNS) and prepare the body for movement, such as walking. By altering the tempo and accentuating the beat of the music, participants unconsciously alter
their gait.12 The areas in the CNS responsible for processing music (left inferior parietal and prefrontal cerebellar circuits) also process dyspnea, which is thought to happen below the level of consciousness.13 For this reason, it is hypothesized that, the CNS processing of music may help override the conscious perception of dyspnea. Overriding the conscious perception of dyspnea, may help Participant’s to walk further and longer.7 The purpose of this study was to compare walking distance and perceived dyspnea in participants with COPD under three different 6 Min Walk Test (6MWT) conditions: (1) walking while listening to RAS-enhanced music, (2) walking while listening to music without rhythm enhancement and (3) walking without music. It was hypothesized that participants with COPD would walk further and report less dyspnea during a 6MWT while listening to RAS-enhanced music as compared to a 6MWT while listening to music without rhythmic enhancement or without listening to music.11 Methods
* Correspondingauthor. E-mail addresses: [email protected] (A. Hernandez), [email protected] (U.G. Bronas), [email protected] (A.D. Steffen), [email protected] (D.X. Marquez), [email protected] (C. Fritschi), [email protected] (L.T. Quinn), [email protected] (E.G. Collins). https://doi.org/10.1016/j.hrtlng.2020.01.006 0147-9563/© 2020 Elsevier Inc. All rights reserved.
Study design A repeated-measures study design was used. The study was conducted in a single visit.
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Participants Participants were recruited between April and October of 2017. Participants were recruited by a letter of invitation or by responding to a flyer. Inclusion criteria were: >40 years of age, FEV1/FVC < 70%, FEV1 70%, and ability to walk without assistance. Exclusion criteria were: inability to hear, respiratory infection / exacerbations within the previous four weeks, heart failure (New York Heart Association Class III or IV), and exercise-limiting peripheral arterial disease or arthritis. The Mini Mental State Exam was administered to screen for cognitive impairment, as beat perception can be compromised in those with cognitive impairment.74 Participant’s with a score <23 were not be eligible to participate in the study. No participant was excluded based on gender or ethnicity. Institutional Review Board approval was obtained from the Edward Hines Jr., VA Hospital and the University of Illinois at Chicago (UIC). Informed consent was obtained prior to study initiation. Measurement instruments Six minute walk test (6MWT) The 6MWTs were conducted according to the American Thoracic Society (ATS) guidelines.14 The major exceptions to the ATS guidelines were that participants were not coached and they were not notified of how far along they were in the walk. We did not use visual cues or notifications for elapsed time as it would draw participant’s attention away from the music. It was posited that interrupting participant’s during the music walks would disrupt the rhythm created by the music, and draw attention to their breathing. Making it difficult to ascertain if music provided a distraction from dyspnea. Participants were asked to walk up and down a 100-foot corridor as fast as they could without running. They turned around a cone placed in the corridor at each end of the walk. Participants were allowed to stop and rest if needed and were instructed to advise the investigator when they began to feel short of breath or breathless. Participant’s rated their dyspnea on the modified BORG scale before and after the walks (or during if they stopped or felt a notable difference in dyspnea during walks). The BORG scale was printed on paper with a 20point type font size.15 Using the 6MWT, maximal walking distance, walking cadence and perceived dyspnea free distance in meters. Onset of dyspnea was defined as the initial distance when the participant reported mild dyspnea. If the participant did not report dyspnea during the 6MWT, dyspnea onset was recorded as the maximal distance walked. Walking cadence was measured three times during the 6MWT. One researcher counted the number of steps that the participants took during the 6MWT between 1 and 2 min, 3 and 4 min, and 5 and 6 min. Vital signs (blood pressure, heart rate, SpO2) were obtained prior to and after every 6MWT to ensure safe return to baseline. 6MWT practice test was not performed for several reasons. First, we wanted to decrease study burden on participants. Second, participants were familiar with 6MWT as they had histories of participating in pulmonary rehabilitation (>6months). In order to reduce the order effect, we randomized the conditions for the order of the three walks. Modified borg scale (MBS) A MBS was used to measure dyspnea during the 6MWT.3,16,17 It is an interval, self-rated scale in which symptoms of breathlessness were estimated by the participant between 0 (not at all), 0.5 for “very, very slight (just noticeable), and 10 (maximal).18,19,16,20 Initial walking cadence Participants were asked to walk at a normal speed on a flat surface for 30 s. The number of steps were counted and multiplied by 2 to
obtain steps/minute. This number was used as the participant’s preferred walking speed.12 The number of steps/minute was used to calculate the tempo of the music for the walks involving music (i.e. rhythmically enhanced and not rhythmically enhanced). Data collection Demographic information and a brief medical history were obtained. Pulmonary function test data were extracted from the participant’s electronic medical records and were used to describe lung function severity. Participants were randomized to receive a specified order of walking condition to ensure balance across participants and reduce possible order effects. Study participation was completed in one visit at the physical performance laboratory at the VA hospital. Participants were told that they would complete two of the three 6MWTs to music and were not alerted to differences in music. Normal walking cadence was determined prior to testing.12 The music tempo for the “as recorded” walk approximated the participant’s preferred walking cadence. For the RAS walk, the tempo was increased to 5 10 beats per minute higher than the preferred walking cadence.21 Participant’s rested for 15 min before performing the first 6MWT, and 30 min between tests. Participants were provided a list of popular songs/genres to choose from for walks involving music (genres options included pop, country western, big band, gospel, classic rock, jazz, and blues). All songs were arranged in 6-minute loops to fit the 6MWT time. The tempo of the RAS modified songs ranged from 90 150 beats per minute. The music was preloaded onto iPod Ò Touch and BoseÒ stereo earphones were placed on participants during walks involving music. Modifications to RAS tempo and rhythm were made using Audacity software (version 2.1.2!). Two study coordinators administered the 6MWT. One operated the iPod and set up the appropriate walk condition. The other, blinded to the music condition, recorded the lap time, cadence and dyspnea onset. Participant’s held the iPod Ò while walking. Statistical analysis Descriptive statistics (mean, standard deviation) were used to describe the sample. Paired-sample t-tests were used to compare the walking distances between pairs of the three walking conditions (no music to music without enhancement, music without enhancement, to RAS, and no music to RAS), onset of dyspnea and peak dyspnea. One-way analyses of variance (ANOVA) was used to assess if there were differences attributed to walk order for each type of walk condition. The sample size calculation was based on the mean difference of walk distance with RAS and no music from a pilot study using a different clinical sample, participants with peripheral artery disease. The effect size for this group was = 0.83. It was estimated that a sample size of 14 was needed to achieve 80% power to detect a difference (of the same magnitude using a two-sided test and significance level of = 0.05). We conservatively targeted to recruit 30 participants allowing for a smaller effect in persons with COPD. SPSS (IBM Corp. Released 2016. IBM SPSS Statistics for Windows, Version 24.0. Armonk, NY: IBM Corp.) was used to calculate all statistical results. Results Characteristics of participant’s Twenty-five adult men (age = 61 80 years), with moderate-tosevere COPD (FEV1 = 47.4 § 9.7% predicted), were recruited and completed the study protocol. Three participant’s used supplemental oxygen to complete the study protocol. Participants had a mean preferred walking cadence of 103 § 8 steps/minute. See Table 1 for
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the walking condition and differed significantly comparing RAS to no music at the 1 2 (p = 0.005), 3 4 (p = 0.002) and 5 6 (p = 0.004) minute measurement points. Walking cadence in the RAS condition was also greater at the 5 6-minute time point than the music condition (p = 0.003).
Table 1 Characteristics of study population (n = 25). Variable
Mean (SD)
Age Smoking (Pack Years) 60 sec step count BMI FEV1/FVC (%) FVC FEV1% predicted Charlson Co-morbidity Index Mmrc
70.7 (4.5) 49.0 (31.4) 103.0 (7.9) 27.0 (4) 47.3 (9.7) 3.0 (0.77) 46.6 (14.8) 1.84 (0.98) 1.0 (0.64)
3
Discussion The major finding of this study is that participant’s walked further during a 6MWT when listening to rhythmically enhanced music as compared to music without enhancement or no music. Walking cadence in all three-minute intervals was increased when comparing RAS and no music walking condition. Additionally, no significant difference in onset or peak dyspnea was found when comparing walks. A 12 m gain in walk distance (versus 25 30 m)22 is not clinically significant. The 25 30 m clinically significant change is a standard used after a 12-week exercise training intervention.22 Therefore, realizing a 12 m increase at baseline, without 12 weeks of exercise training is promising. A longer, randomized controlled trial using similar interventions may be useful to determine clinically meaningful changes in walk distance when participants are exposed over time.22 24 Finding a significant increase in walking distance under the RAS 6MWT condition builds on the evidence that the RAS enhanced music may trigger subconscious neurological pathways that affect motoric response to rhythm and tempo.11,25 The results from the present study support the notion that increasing the bass and tempo of music helped participant’s increase their cadence. To the author’s knowledge, this is the first study to investigate the effects of RAS enhanced music on 6-Minute Walk Distance (6MWD) in participants with moderate-to-severe COPD. Previous studies have demonstrated that the music (not RAS) distracts dyspnea and can enhance physical performance.7 Music makes it easier for participant’s to stay motivated, and achieve greater gains in distance covered by following the tempo of the music.7,21,24,26 28 Bronas, et al. demonstrated that using RAS music to prescribe walking intensity in a home-based walking program for participant’s with peripheral artery disease resulted in significant gains in walk distance (48 m).25 Current study findings identified lesser gains in 6MWD with RAS over music as recorded and no music which may be due to the differences in clinical manifestations of dyspnea versus claudication pain. Additionally, participants from the peripheral artery disease study had higher base cadence and were prescribed music with a higher tempo.25 Dyspnea may be perceived as more uncomfortable and potentially life-threatening than claudication pain and thus avoided.
SD = standard deviation, Pack/years = smoking in pack years, Charlson score = Charlson Comorbidity Score (higher number = more comorbidities), BMI = body mass index 60 s step count = baseline cadence, mMRC = Modified Medical Research Council breathless scale (higher numbers indicate worse condition). Distance for walk conditions reported in meters (1 meter = 3.28084 feet).
additional demographic information. There were no adverse events related to the study procedure. No participant stopped to rest. 6MWT Dyspnea, cadence There were no differences in distance walked based on the order in which the walk occurred for any of the walking conditions. Oneway ANOVA assessing differences in walk order for each walking condition follows: no music (F = 0.37, df = 2, p = 0.964), music (F = 0.277, df = 2, p = 0.761), and RAS (F = 0.385, df = 2, p = 0.685). Lack of order effects supports that differences between walking conditions are due to the condition of the walk. Participant’s walked 12 m, 95% CI [20.5-, 2.6], p = 0.015 further during the 6MWT when listening to RAS-enhanced music (463 § 72 m) when compared to walking without music (451 § 81 m); t (24) = 2.63, p = 0.015) or walking with music without rhythm enhancement (451 § 80 m); t (24) = 2.26, p = 0.033) (see Table 2). There were no differences in distance walked between the no music condition and the music without rhythm enhancement condition 95% CI 95% CI [10.7.,11.2] (t (24) = 0.50, p = 0.960). There were no differences in the onset of dyspnea or the perception of dyspnea at peak exercise (i.e. dyspnea at the end of each respective walk) amongst the different walking conditions (Table 2). Cadence measured during the 6MWT, between minutes 1 2, 3 4, and 5 6 for all three walk conditions are reported in Table 3. Walking cadence was consistent at the three intervals examined within
Table 2 Primary outcomes: 6-minute walk distance and perceived dyspnea (n = 25).
Variable
Mean (SD) NM
Mean (SD) Music
Mean (SD) RAS
P value NM-M
P value NM-RAS
P value M-RAS
6MWD (m) Dyspnea onset (m) Dyspnea peak (1 10 scale)
451. 0 (80.6) 378.0 (121.0) 2.7 (1.7)
451.0 (79.6) 391.0 (134.0) 2.4 (1.8)
463.0 (71.8) 399.0 (143.0) 2.5 (1.6)
0.960 0.543 0.121
0.015* 0.307 0.317
0.033* 0.576 0.525
* = statistical significance paired t-test, 6MWD = Six Minute Walk Distance in meters, Onset dyspnea = dyspnea free walk distance, Peak dyspnea = dyspnea at the end of the 6 min walk (Modified Borg Scale of 1 to 10), NM = no music, M = music as recorded, RAS = Rhythmic Auditory Stimulation, 1 meter = 3.28084 feet.
Table 3 Walk Cadence during 6MWT (n = 25). Variable
Mean (SD) NM
Mean (SD) MC
Significance NM-M
Mean (SD) RAS
Significance NM-RAS
Significance M-RAS
Cadence 1 2 (min) Cadence 3 4 (min) Cadence 5 6 (min)
105 (9) 107 (12) 107 (13)
108 (11) 108 (13) 108 (13)
0.022* 0.368 0.367
110 (12) 110 (10) 110 (11)
0.005* 0.002* 0.004*
0.110 0.092 0.003*
* = statistical significance paired t-test, min = minute, cadence = step/min, NM = no music, M = music as recorded, RAS = Rhythmic Auditory Stimulation.
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We only identified one additional study that investigated the use of RAS enhanced music to prescribe walking intensity for a supervised and home-based exercise program in Korean Participant’s with COPD. Ho, et al. demonstrated that using RAS enhanced music to prescribe walking pace during an exercise intervention helped participant’s achieve higher exercise capacity (243.5 m § 135.4 versus 306.0 § 107.3, p < 0.001).23 While our study did not use RAS enhanced music as a prescriptive tool and we did not measure exercise capacity, the findings suggest that RAS enhanced music may increase 6MWD in Participant’s with COPD. There was a significant increase in cadence across all three-minute intervals when comparing the cadence of the RAS enhanced walk condition to that of No Music. Additionally, participants were able to match the elevated tempo of the RAS music during the entire 6MWT (110 § 12). This observation may support the premise that beat perception mechanisms can be neurologically entrained.11,12 However, it is important to note that the variance was very narrow amongst all walk cadence conditions in all minute intervals. Most interventions reporting the use of music tempo to prescribe walking pace have been used during an intervention requiring the participant to consciously attempt to walk to the beat of the tempo.23 This is because, physiologically auditory- motor coordination requires time and exposure to the musical cue so that gait can adjust to the beat.12 Gait will couple best to a beat closest to the participant’s preferred cadence, and increasing the beat of music too much may compromise motor coordination.12,29 In the present study we only increased the tempo by 5 10 beats above baseline cadence for the RAS condition, and did not expose participant’s to the music before walks to reduce study burden. With these considerations, the study results may suggest that it was the music and not the enhancement of the music that was prompting increases in walk cadence. Further investigation is warranted on how to precisely prescribe a cadence rate that promotes safe prolonged bouts of movement without compromising gait patterns in this population. Participants were instructed to report dyspnea during the 6MWT. Participant’s provided a rating for peak dyspnea once the walk concluded, but some did not report onset. No significant difference in perceived onset of dyspnea or peak dyspnea were found. The participants in the study may have been less aware of their dyspnea due to the music. Neurologically, music is thought to override the attention centers of the brain where noxious stimuli such as dyspnea are processed, and help release endorphins while generating feelings of calmness.30 Chronic feelings of breathlessness can provoke anxiety and real fear.26 Desensitization and distraction have been effective in reducing dyspnea and anxiety.26,31 33 For this reason, music has been used extensively as a cognitive behavioral distractive strategy to increase physical performance in chronically ill participant’s distracting them from uncomfortable symptoms.7,8,34,35 Bauldoff, et al. reported that perceived dyspnea was reduced during the 6MWT coupled with an increase in walk distance in the group that received the music compared to the group that did not during a home-based walking program.7 Additionally, participant’s assigned to the music group reported less dyspnea during activities of daily living.7 Other studies by, Tsai,8 von Leupoldt,34 Bellini 35 have also found evidence to support the use of music as a distractive tool for the management of uncomfortable symptoms. This finding could also reflect that the participants were not pushing themselves beyond a level of dyspnea they felt comfortable with. Finding no significant difference in onset or peak dyspnea among the walks, despite the increase in walking distance, warrants further investigation on the use of music as a distractive strategy in this population. Strengths and limitations The sample was composed entirely of older, male participants who were mostly white. As such, our results are not generalizable to
other ages, women or minorities. Participants may have been more inclined to join in exercise rehabilitation, than the general population. Randomizing the three walks allowed us to control for order effect for the 6MWT. Additionally, we measured walking cadence, which has often been underreported. We conservatively targeted to recruit 30 participants allowing for a smaller effect in persons with COPD. We were able to recruit and complete all study components for 25 participants. We asked participants to report onset of dyspnea, but did not remind them once walks had initiated as to not to alter the distractive effects of the RAS and/or music. We cannot rule out that participant’s forgot the initial instructions to self-report onset of dyspnea, or perhaps, the music conditions did in fact distract them from the onset of the symptoms. An additional explanation for this finding is that the sample was composed entirely of men and there is evidence to suggest that men tend to underreport symptoms of dyspnea compared to women.36 40 Lastly, a type II error may have occurred in that the sample size may have been too small and variability in dyspnea onset too great to detect a significant difference in dyspnea onset. Conclusions This study provided evidence that walking with RAS enhanced music may have a positive effect on 6MWD among participant’s with moderate-to-severe COPD. Increases in walking distance during 6MWT using RAS enhanced music provide preliminary support for the use of RAS enhanced music as a potential intervention for a center based, as well as, home-based exercise-walking program. Acknowledgements Thank you to the participants who participated in this study as well as the staff of the Physical Performance Laboratory at the Edward Hines Jr., VA Hospital. Funding Department of Veterans Affairs, Rehabilitation Research & Development. References 1. National Center for Health Statistics. Health USwSFoRaEHDH. MD: US Dept. Health and Human Services; 2016. http://www.cdc.gov/nchs/hus/. Accessed June 2016. 2. Terzikhan N, Verhamme KMC, Hofman A, Stricker BH, Brusselle GG, Lahousse L. Prevalence and incidence of COPD in smokers and non-smokers: The rotterdam study. Eur J Epidemiol. 2016;31(8):785–792. 3. Nici L, Donner C, Wouters E, et al. American Thoracic Society/European Respiratory Society statement on pulmonary rehabilitation. Am J Respir Crit Care Med. 2006;173(12):1390–1413. 4. Scano G, Innocenti-Bruni G, Stendardi L. Do obstructive and restrictive lung diseases share common underlying mechanisms of breathlessness? Respir Med. 2010;104(7):925–933. 5. Waschki B, Kirsten AM, Holz O, et al. Disease progression and changes in physical activity in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2015;192(3):295–306. 6. Lange P, Celli B, Agusti A, et al. Lung-Function trajectories leading to chronic obstructive pulmonary disease. N Engl J Med. 2015;373(2):111–122. 7. Bauldoff GS, Hoffman LA, Zullo TG, Sciurba FC. Exercise maintenance following pulmonary rehabilitation: effect of distractive stimuli. Chest. 2002;122(3):948–954. 8. von Leupoldt A, Taube K, Schubert-Heukeshoven S, Magnussen H, Dahme B. Distractive auditory stimuli reduce the unpleasantness of dyspnea during exercise in patients with COPD. Chest. 2007;132(5):1506–1512. 9. Metcalfe T. The contribution of different musical variables to the effect of background music on motor behavior. Psychomusicology: Music, Mind, and Brain. 2016;26(2):132–138. k M, van Noorden L, Rezny L. Tempo and walking speed with music in the 10. Frane urban context. Front Psychol. 2014;5:1361. -1361. 11. Thaut MH. The discovery of human auditory-motor entrainment and its role in the development of neurologic music therapy. Prog Brain Res. 2015;217:253–266. 12. Roerdink M, Bank PJ, Peper CL, Beek PJ. Walking to the beat of different drums: practical implications for the use of acoustic rhythms in gait rehabilitation. Gait Posture. 2011;33(4):690–694.
ARTICLE IN PRESS A. Hernandez et al. / Heart & Lung 00 (2020) 1 5 13. Thaut MH. Music therapy, affect modification, and theraputic change: twords an intigrative model. Music Ther Perspect. 1989;7:55–62. 14. Crapo OR, Asaburi RC, Coates AL, et al. ATS Statement: Guidelines for the Six-Minute Walk Test. 2002. 15. American Thoracic Society. ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med. 2002;166:111–117. 16. Borg G. Psychophysical bases of percived exertion medicine and science in sports and exercise1982;14(5):337 381. 17. Parshall MB, Schwartzstein RM, Adams L, et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med. 2012;185(4):435–452. 18. Meek PM, Lareau S. Critical outcomes in pulmonary rehabilitation: assessment and evaluation of dyspnea and fatigue. J Rehabil Res Dev. 2003;40(5):13–24. 19. Kendrick KR, Baxi SC, Smith RM. Usefulness of the modified 0-10 borg scale in assessing the degree of dyspnea in patients with COPD and asthma. J Emerg Nurs. 2000;26(3):216–222. 20. Singh SJ, Puhan MA, Andrianopoulos V, et al. An official systematic review of the European Respiratory Society/American Thoracic Society: Measurement properties of field walking tests in chronic respiratory disease. Eur Respir J. 2014;44(6):1447–1478. 21. Leow LA, Rinchon C, Grahn J. Familiarity with music increases walking speed in rhythmic auditory cuing. Ann N Y Acad Sci. 2015;1337:53–61. 22. Holland AE, Nici L. The return of the minimum clinically important difference for 6-minute-walk distance in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2013;187(4):335–336. 23. Ho CF, Maa SH, Shyu YI, Lai YT, Hung TC, Chen HC. Effectiveness of paced walking to music at home for patients with COPD. COPD. 2012;9(5):447–457. 24. Alter DA, O’Sullivan M, Oh PI, et al. Synchronized personalized music audio-playlists to improve adherence to physical activity among patients participating in a structured exercise program: a proof-of-principle feasibility study. Sports Med Open. 2015;1(1):7. 25. Bronas UG, Everett S, Steffen A, et al. Rhythmic auditory music stimulation enhances walking distance in patients with claudication: a feasibility study. J Cardiopulm Rehabil Prev. 2017.
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26. Bauldoff GS. Music: more than just a melody. Chron Respir Dis. 2009;6(4):195–197. 27. Bauldoff GS, Hoffman LA, Zullo TG, Sciurba FC. Exercise maintenance following pulmonary rehabilitation*: effect of distractive stimuli. Chest. 2002;122(3):948–954. 28. Leow LA, Parrott T, Grahn JA. Individual differences in beat perception affect gait responses to low- and high-groove music. Front Hum Neurosci. 2014;8:811. 29. Karageorghis CI, Priest DL. Music in the exercise domain: a review and synthesis (Part I). Int Rev Sport Exerc Psychol. 2012;5(1):44–66. 30. Brody R. Music medicine. Omni. 1984;6:110–116. 31. Smoller JW PM, Ottto MW, Rosenbaum JF, Kradin RL. State of the art: Panic anxiety, dyspnea and respiratory disease. Am J Res Crit Care Med. 1996;154:6–17. 32. Gift AG MT, Soeken K. Relaxation to reduce dyspnea and anxiety in COPD patients. Nurs Res. 1992;41:242–246. 33. Renfroe KL. Effect of progressive relaxation on dyspnea and state anxiety in patients with chronic obstructive pulmonary disease. Heart Lung. 1988;17:408–413. 34. Tsai HF, Chen YR, Chung MH, et al. Effectiveness of music intervention in ameliorating cancer patients' anxiety, depression, pain, and fatigue: a meta-analysis. Cancer Nurs. 2014;37(6):E35–E50. 35. Bellieni C, Cioncoloni D, Mazzanti S, et al. Music provided through a portable media player (iPod) blunts pain during physical therapy. Pain Manag Nurs. 2013;14(4): e151–e155. 36. Aryal S, Diaz-Guzman E, Mannino DM. COPD and gender differences: an update. Transl Res. 2013;162(4):208–218. 37. Bea Lamprecht. Sex-related differences in respiratory symptoms: results from the bold study. Eur Res J. 2013:(42):858–886. 38. Camp PG, O'Donnell DE, Postma DS. Chronic obstructive pulmonary disease in men and women: myths and reality. Proc Am Thorac Soc. 2009;6(6):535–538. 39. Johnson JL, Campbell AC, Bowers M, Nichol AM. Understanding the social consequences of chronic obstructive pulmonary disease: the effects of stigma and gender. Proc Am Thorac Soc. 2007;4(8):680–682. 40. Watson L, Vestbo J, Postma DS, et al. Gender differences in the management and experience of chronic obstructive pulmonary disease. Respir Med. 2004;98 (12):1207–1213.
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Rhythmic auditory stimulation increases 6-Minute walk distance in individuals with COPD: A repeated measures study Alison Hernandeza,b,*, Ulf G. Bronasb, Alana D. Steffenb, David X. Marquezc, Cynthia Fritschib, Lauretta T. Quinnb, Eileen G. Collinsb,d a
Northwestern University, Feinberg School of Medicine, Center for Education in Health Science and Outcomes Research, 633 N St. Clair, 20th Floor (2024-J), Chicago, IL 60611 University of Illinois at Chicago, College of Nursing, 845 South Damen Ave, Chicago IL 60612 c University of Illinois at Chicago, Department of Kinesiology and Nutrition, 1919 W. Taylor, Chicago IL 60612 d Edward Hines Jr., VA Hospital b
A R T I C L E
I N F O
Article History: Received 5 September 2019 Revised 20 January 2020 Accepted 22 January 2020 Available online xxx Keywords: COPD Exercise Music 6-minute walk test Rhythmic auditory stimulation
A B S T R A C T
Objective: To evaluate if there is an increase in 6-minute walk distance in individuals with chronic obstructive pulmonary disease (COPD) while walking to rhythmically enhanced music. Background: Individuals with COPD are less active. Walking with rhythmically enhanced music may help Participant’s walk farther while simultaneously distracting from symptoms of dyspnea. Methods: Twenty-five men (age = 70.7 § 4.5 yr), with moderate-to-severe COPD (FEV1 = 47.4 § 9.7% predicted) completed three, 6 min walk tests (6MWT) in random order. Walks were completed with music, with music that was rhythmically enhanced, or without music. Walking distance and perceived dyspnea were measured. Results: Participant’s walked 12 m, 95% CI [20.5-, 2.6], p = 0.015 further during the 6MWT when listening to rhythmically enhanced music when compared to no music. Onset of dyspnea was not different between the three walking conditions. Conclusions: Rhythmically-enhanced music may be a useful tool to increase walking distance in Participant’s with COPD. © 2020 Elsevier Inc. All rights reserved.
Introduction More than 14.5 million individuals are living with chronic obstructive pulmonary disease (COPD), which is the third cause of death worldwide.1,2 Individuals with COPD have reduced exercise tolerance and experience symptoms of dyspnea.3 6 Interventions to enhance exercise tolerance and minimize the perception of dyspnea are important. Listening to music can distract from the perception of dyspnea;7,8 and enhance arousal by priming the body for motor behaviors such as walking.9 Additionally, listening to rhythmic music with an upbeat tempo may increase walking speed in young adult men and women.10 Rhythmic auditory stimulation (RAS) is the process of using music with rhythm and tempo enhancement (i.e. increasing bass and tempo) to entrain the body for movement.11 The rhythm and tempo of music prime the central nervous system (CNS) and prepare the body for movement, such as walking. By altering the tempo and accentuating the beat of the music, participants unconsciously alter
their gait.12 The areas in the CNS responsible for processing music (left inferior parietal and prefrontal cerebellar circuits) also process dyspnea, which is thought to happen below the level of consciousness.13 For this reason, it is hypothesized that, the CNS processing of music may help override the conscious perception of dyspnea. Overriding the conscious perception of dyspnea, may help Participant’s to walk further and longer.7 The purpose of this study was to compare walking distance and perceived dyspnea in participants with COPD under three different 6 Min Walk Test (6MWT) conditions: (1) walking while listening to RAS-enhanced music, (2) walking while listening to music without rhythm enhancement and (3) walking without music. It was hypothesized that participants with COPD would walk further and report less dyspnea during a 6MWT while listening to RAS-enhanced music as compared to a 6MWT while listening to music without rhythmic enhancement or without listening to music.11 Methods
* Correspondingauthor. E-mail addresses: [email protected] (A. Hernandez), [email protected] (U.G. Bronas), [email protected] (A.D. Steffen), [email protected] (D.X. Marquez), [email protected] (C. Fritschi), [email protected] (L.T. Quinn), [email protected] (E.G. Collins). https://doi.org/10.1016/j.hrtlng.2020.01.006 0147-9563/© 2020 Elsevier Inc. All rights reserved.
Study design A repeated-measures study design was used. The study was conducted in a single visit.
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Participants Participants were recruited between April and October of 2017. Participants were recruited by a letter of invitation or by responding to a flyer. Inclusion criteria were: >40 years of age, FEV1/FVC < 70%, FEV1 70%, and ability to walk without assistance. Exclusion criteria were: inability to hear, respiratory infection / exacerbations within the previous four weeks, heart failure (New York Heart Association Class III or IV), and exercise-limiting peripheral arterial disease or arthritis. The Mini Mental State Exam was administered to screen for cognitive impairment, as beat perception can be compromised in those with cognitive impairment.74 Participant’s with a score <23 were not be eligible to participate in the study. No participant was excluded based on gender or ethnicity. Institutional Review Board approval was obtained from the Edward Hines Jr., VA Hospital and the University of Illinois at Chicago (UIC). Informed consent was obtained prior to study initiation. Measurement instruments Six minute walk test (6MWT) The 6MWTs were conducted according to the American Thoracic Society (ATS) guidelines.14 The major exceptions to the ATS guidelines were that participants were not coached and they were not notified of how far along they were in the walk. We did not use visual cues or notifications for elapsed time as it would draw participant’s attention away from the music. It was posited that interrupting participant’s during the music walks would disrupt the rhythm created by the music, and draw attention to their breathing. Making it difficult to ascertain if music provided a distraction from dyspnea. Participants were asked to walk up and down a 100-foot corridor as fast as they could without running. They turned around a cone placed in the corridor at each end of the walk. Participants were allowed to stop and rest if needed and were instructed to advise the investigator when they began to feel short of breath or breathless. Participant’s rated their dyspnea on the modified BORG scale before and after the walks (or during if they stopped or felt a notable difference in dyspnea during walks). The BORG scale was printed on paper with a 20point type font size.15 Using the 6MWT, maximal walking distance, walking cadence and perceived dyspnea free distance in meters. Onset of dyspnea was defined as the initial distance when the participant reported mild dyspnea. If the participant did not report dyspnea during the 6MWT, dyspnea onset was recorded as the maximal distance walked. Walking cadence was measured three times during the 6MWT. One researcher counted the number of steps that the participants took during the 6MWT between 1 and 2 min, 3 and 4 min, and 5 and 6 min. Vital signs (blood pressure, heart rate, SpO2) were obtained prior to and after every 6MWT to ensure safe return to baseline. 6MWT practice test was not performed for several reasons. First, we wanted to decrease study burden on participants. Second, participants were familiar with 6MWT as they had histories of participating in pulmonary rehabilitation (>6months). In order to reduce the order effect, we randomized the conditions for the order of the three walks. Modified borg scale (MBS) A MBS was used to measure dyspnea during the 6MWT.3,16,17 It is an interval, self-rated scale in which symptoms of breathlessness were estimated by the participant between 0 (not at all), 0.5 for “very, very slight (just noticeable), and 10 (maximal).18,19,16,20 Initial walking cadence Participants were asked to walk at a normal speed on a flat surface for 30 s. The number of steps were counted and multiplied by 2 to
obtain steps/minute. This number was used as the participant’s preferred walking speed.12 The number of steps/minute was used to calculate the tempo of the music for the walks involving music (i.e. rhythmically enhanced and not rhythmically enhanced). Data collection Demographic information and a brief medical history were obtained. Pulmonary function test data were extracted from the participant’s electronic medical records and were used to describe lung function severity. Participants were randomized to receive a specified order of walking condition to ensure balance across participants and reduce possible order effects. Study participation was completed in one visit at the physical performance laboratory at the VA hospital. Participants were told that they would complete two of the three 6MWTs to music and were not alerted to differences in music. Normal walking cadence was determined prior to testing.12 The music tempo for the “as recorded” walk approximated the participant’s preferred walking cadence. For the RAS walk, the tempo was increased to 5 10 beats per minute higher than the preferred walking cadence.21 Participant’s rested for 15 min before performing the first 6MWT, and 30 min between tests. Participants were provided a list of popular songs/genres to choose from for walks involving music (genres options included pop, country western, big band, gospel, classic rock, jazz, and blues). All songs were arranged in 6-minute loops to fit the 6MWT time. The tempo of the RAS modified songs ranged from 90 150 beats per minute. The music was preloaded onto iPod Ò Touch and BoseÒ stereo earphones were placed on participants during walks involving music. Modifications to RAS tempo and rhythm were made using Audacity software (version 2.1.2!). Two study coordinators administered the 6MWT. One operated the iPod and set up the appropriate walk condition. The other, blinded to the music condition, recorded the lap time, cadence and dyspnea onset. Participant’s held the iPod Ò while walking. Statistical analysis Descriptive statistics (mean, standard deviation) were used to describe the sample. Paired-sample t-tests were used to compare the walking distances between pairs of the three walking conditions (no music to music without enhancement, music without enhancement, to RAS, and no music to RAS), onset of dyspnea and peak dyspnea. One-way analyses of variance (ANOVA) was used to assess if there were differences attributed to walk order for each type of walk condition. The sample size calculation was based on the mean difference of walk distance with RAS and no music from a pilot study using a different clinical sample, participants with peripheral artery disease. The effect size for this group was = 0.83. It was estimated that a sample size of 14 was needed to achieve 80% power to detect a difference (of the same magnitude using a two-sided test and significance level of = 0.05). We conservatively targeted to recruit 30 participants allowing for a smaller effect in persons with COPD. SPSS (IBM Corp. Released 2016. IBM SPSS Statistics for Windows, Version 24.0. Armonk, NY: IBM Corp.) was used to calculate all statistical results. Results Characteristics of participant’s Twenty-five adult men (age = 61 80 years), with moderate-tosevere COPD (FEV1 = 47.4 § 9.7% predicted), were recruited and completed the study protocol. Three participant’s used supplemental oxygen to complete the study protocol. Participants had a mean preferred walking cadence of 103 § 8 steps/minute. See Table 1 for
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the walking condition and differed significantly comparing RAS to no music at the 1 2 (p = 0.005), 3 4 (p = 0.002) and 5 6 (p = 0.004) minute measurement points. Walking cadence in the RAS condition was also greater at the 5 6-minute time point than the music condition (p = 0.003).
Table 1 Characteristics of study population (n = 25). Variable
Mean (SD)
Age Smoking (Pack Years) 60 sec step count BMI FEV1/FVC (%) FVC FEV1% predicted Charlson Co-morbidity Index Mmrc
70.7 (4.5) 49.0 (31.4) 103.0 (7.9) 27.0 (4) 47.3 (9.7) 3.0 (0.77) 46.6 (14.8) 1.84 (0.98) 1.0 (0.64)
3
Discussion The major finding of this study is that participant’s walked further during a 6MWT when listening to rhythmically enhanced music as compared to music without enhancement or no music. Walking cadence in all three-minute intervals was increased when comparing RAS and no music walking condition. Additionally, no significant difference in onset or peak dyspnea was found when comparing walks. A 12 m gain in walk distance (versus 25 30 m)22 is not clinically significant. The 25 30 m clinically significant change is a standard used after a 12-week exercise training intervention.22 Therefore, realizing a 12 m increase at baseline, without 12 weeks of exercise training is promising. A longer, randomized controlled trial using similar interventions may be useful to determine clinically meaningful changes in walk distance when participants are exposed over time.22 24 Finding a significant increase in walking distance under the RAS 6MWT condition builds on the evidence that the RAS enhanced music may trigger subconscious neurological pathways that affect motoric response to rhythm and tempo.11,25 The results from the present study support the notion that increasing the bass and tempo of music helped participant’s increase their cadence. To the author’s knowledge, this is the first study to investigate the effects of RAS enhanced music on 6-Minute Walk Distance (6MWD) in participants with moderate-to-severe COPD. Previous studies have demonstrated that the music (not RAS) distracts dyspnea and can enhance physical performance.7 Music makes it easier for participant’s to stay motivated, and achieve greater gains in distance covered by following the tempo of the music.7,21,24,26 28 Bronas, et al. demonstrated that using RAS music to prescribe walking intensity in a home-based walking program for participant’s with peripheral artery disease resulted in significant gains in walk distance (48 m).25 Current study findings identified lesser gains in 6MWD with RAS over music as recorded and no music which may be due to the differences in clinical manifestations of dyspnea versus claudication pain. Additionally, participants from the peripheral artery disease study had higher base cadence and were prescribed music with a higher tempo.25 Dyspnea may be perceived as more uncomfortable and potentially life-threatening than claudication pain and thus avoided.
SD = standard deviation, Pack/years = smoking in pack years, Charlson score = Charlson Comorbidity Score (higher number = more comorbidities), BMI = body mass index 60 s step count = baseline cadence, mMRC = Modified Medical Research Council breathless scale (higher numbers indicate worse condition). Distance for walk conditions reported in meters (1 meter = 3.28084 feet).
additional demographic information. There were no adverse events related to the study procedure. No participant stopped to rest. 6MWT Dyspnea, cadence There were no differences in distance walked based on the order in which the walk occurred for any of the walking conditions. Oneway ANOVA assessing differences in walk order for each walking condition follows: no music (F = 0.37, df = 2, p = 0.964), music (F = 0.277, df = 2, p = 0.761), and RAS (F = 0.385, df = 2, p = 0.685). Lack of order effects supports that differences between walking conditions are due to the condition of the walk. Participant’s walked 12 m, 95% CI [20.5-, 2.6], p = 0.015 further during the 6MWT when listening to RAS-enhanced music (463 § 72 m) when compared to walking without music (451 § 81 m); t (24) = 2.63, p = 0.015) or walking with music without rhythm enhancement (451 § 80 m); t (24) = 2.26, p = 0.033) (see Table 2). There were no differences in distance walked between the no music condition and the music without rhythm enhancement condition 95% CI 95% CI [10.7.,11.2] (t (24) = 0.50, p = 0.960). There were no differences in the onset of dyspnea or the perception of dyspnea at peak exercise (i.e. dyspnea at the end of each respective walk) amongst the different walking conditions (Table 2). Cadence measured during the 6MWT, between minutes 1 2, 3 4, and 5 6 for all three walk conditions are reported in Table 3. Walking cadence was consistent at the three intervals examined within
Table 2 Primary outcomes: 6-minute walk distance and perceived dyspnea (n = 25).
Variable
Mean (SD) NM
Mean (SD) Music
Mean (SD) RAS
P value NM-M
P value NM-RAS
P value M-RAS
6MWD (m) Dyspnea onset (m) Dyspnea peak (1 10 scale)
451. 0 (80.6) 378.0 (121.0) 2.7 (1.7)
451.0 (79.6) 391.0 (134.0) 2.4 (1.8)
463.0 (71.8) 399.0 (143.0) 2.5 (1.6)
0.960 0.543 0.121
0.015* 0.307 0.317
0.033* 0.576 0.525
* = statistical significance paired t-test, 6MWD = Six Minute Walk Distance in meters, Onset dyspnea = dyspnea free walk distance, Peak dyspnea = dyspnea at the end of the 6 min walk (Modified Borg Scale of 1 to 10), NM = no music, M = music as recorded, RAS = Rhythmic Auditory Stimulation, 1 meter = 3.28084 feet.
Table 3 Walk Cadence during 6MWT (n = 25). Variable
Mean (SD) NM
Mean (SD) MC
Significance NM-M
Mean (SD) RAS
Significance NM-RAS
Significance M-RAS
Cadence 1 2 (min) Cadence 3 4 (min) Cadence 5 6 (min)
105 (9) 107 (12) 107 (13)
108 (11) 108 (13) 108 (13)
0.022* 0.368 0.367
110 (12) 110 (10) 110 (11)
0.005* 0.002* 0.004*
0.110 0.092 0.003*
* = statistical significance paired t-test, min = minute, cadence = step/min, NM = no music, M = music as recorded, RAS = Rhythmic Auditory Stimulation.
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We only identified one additional study that investigated the use of RAS enhanced music to prescribe walking intensity for a supervised and home-based exercise program in Korean Participant’s with COPD. Ho, et al. demonstrated that using RAS enhanced music to prescribe walking pace during an exercise intervention helped participant’s achieve higher exercise capacity (243.5 m § 135.4 versus 306.0 § 107.3, p < 0.001).23 While our study did not use RAS enhanced music as a prescriptive tool and we did not measure exercise capacity, the findings suggest that RAS enhanced music may increase 6MWD in Participant’s with COPD. There was a significant increase in cadence across all three-minute intervals when comparing the cadence of the RAS enhanced walk condition to that of No Music. Additionally, participants were able to match the elevated tempo of the RAS music during the entire 6MWT (110 § 12). This observation may support the premise that beat perception mechanisms can be neurologically entrained.11,12 However, it is important to note that the variance was very narrow amongst all walk cadence conditions in all minute intervals. Most interventions reporting the use of music tempo to prescribe walking pace have been used during an intervention requiring the participant to consciously attempt to walk to the beat of the tempo.23 This is because, physiologically auditory- motor coordination requires time and exposure to the musical cue so that gait can adjust to the beat.12 Gait will couple best to a beat closest to the participant’s preferred cadence, and increasing the beat of music too much may compromise motor coordination.12,29 In the present study we only increased the tempo by 5 10 beats above baseline cadence for the RAS condition, and did not expose participant’s to the music before walks to reduce study burden. With these considerations, the study results may suggest that it was the music and not the enhancement of the music that was prompting increases in walk cadence. Further investigation is warranted on how to precisely prescribe a cadence rate that promotes safe prolonged bouts of movement without compromising gait patterns in this population. Participants were instructed to report dyspnea during the 6MWT. Participant’s provided a rating for peak dyspnea once the walk concluded, but some did not report onset. No significant difference in perceived onset of dyspnea or peak dyspnea were found. The participants in the study may have been less aware of their dyspnea due to the music. Neurologically, music is thought to override the attention centers of the brain where noxious stimuli such as dyspnea are processed, and help release endorphins while generating feelings of calmness.30 Chronic feelings of breathlessness can provoke anxiety and real fear.26 Desensitization and distraction have been effective in reducing dyspnea and anxiety.26,31 33 For this reason, music has been used extensively as a cognitive behavioral distractive strategy to increase physical performance in chronically ill participant’s distracting them from uncomfortable symptoms.7,8,34,35 Bauldoff, et al. reported that perceived dyspnea was reduced during the 6MWT coupled with an increase in walk distance in the group that received the music compared to the group that did not during a home-based walking program.7 Additionally, participant’s assigned to the music group reported less dyspnea during activities of daily living.7 Other studies by, Tsai,8 von Leupoldt,34 Bellini 35 have also found evidence to support the use of music as a distractive tool for the management of uncomfortable symptoms. This finding could also reflect that the participants were not pushing themselves beyond a level of dyspnea they felt comfortable with. Finding no significant difference in onset or peak dyspnea among the walks, despite the increase in walking distance, warrants further investigation on the use of music as a distractive strategy in this population. Strengths and limitations The sample was composed entirely of older, male participants who were mostly white. As such, our results are not generalizable to
other ages, women or minorities. Participants may have been more inclined to join in exercise rehabilitation, than the general population. Randomizing the three walks allowed us to control for order effect for the 6MWT. Additionally, we measured walking cadence, which has often been underreported. We conservatively targeted to recruit 30 participants allowing for a smaller effect in persons with COPD. We were able to recruit and complete all study components for 25 participants. We asked participants to report onset of dyspnea, but did not remind them once walks had initiated as to not to alter the distractive effects of the RAS and/or music. We cannot rule out that participant’s forgot the initial instructions to self-report onset of dyspnea, or perhaps, the music conditions did in fact distract them from the onset of the symptoms. An additional explanation for this finding is that the sample was composed entirely of men and there is evidence to suggest that men tend to underreport symptoms of dyspnea compared to women.36 40 Lastly, a type II error may have occurred in that the sample size may have been too small and variability in dyspnea onset too great to detect a significant difference in dyspnea onset. Conclusions This study provided evidence that walking with RAS enhanced music may have a positive effect on 6MWD among participant’s with moderate-to-severe COPD. Increases in walking distance during 6MWT using RAS enhanced music provide preliminary support for the use of RAS enhanced music as a potential intervention for a center based, as well as, home-based exercise-walking program. Acknowledgements Thank you to the participants who participated in this study as well as the staff of the Physical Performance Laboratory at the Edward Hines Jr., VA Hospital. Funding Department of Veterans Affairs, Rehabilitation Research & Development. References 1. National Center for Health Statistics. Health USwSFoRaEHDH. MD: US Dept. Health and Human Services; 2016. http://www.cdc.gov/nchs/hus/. Accessed June 2016. 2. Terzikhan N, Verhamme KMC, Hofman A, Stricker BH, Brusselle GG, Lahousse L. Prevalence and incidence of COPD in smokers and non-smokers: The rotterdam study. Eur J Epidemiol. 2016;31(8):785–792. 3. Nici L, Donner C, Wouters E, et al. American Thoracic Society/European Respiratory Society statement on pulmonary rehabilitation. Am J Respir Crit Care Med. 2006;173(12):1390–1413. 4. Scano G, Innocenti-Bruni G, Stendardi L. Do obstructive and restrictive lung diseases share common underlying mechanisms of breathlessness? Respir Med. 2010;104(7):925–933. 5. Waschki B, Kirsten AM, Holz O, et al. Disease progression and changes in physical activity in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2015;192(3):295–306. 6. Lange P, Celli B, Agusti A, et al. Lung-Function trajectories leading to chronic obstructive pulmonary disease. N Engl J Med. 2015;373(2):111–122. 7. Bauldoff GS, Hoffman LA, Zullo TG, Sciurba FC. Exercise maintenance following pulmonary rehabilitation: effect of distractive stimuli. Chest. 2002;122(3):948–954. 8. von Leupoldt A, Taube K, Schubert-Heukeshoven S, Magnussen H, Dahme B. Distractive auditory stimuli reduce the unpleasantness of dyspnea during exercise in patients with COPD. Chest. 2007;132(5):1506–1512. 9. Metcalfe T. The contribution of different musical variables to the effect of background music on motor behavior. Psychomusicology: Music, Mind, and Brain. 2016;26(2):132–138. k M, van Noorden L, Rezny L. Tempo and walking speed with music in the 10. Frane urban context. Front Psychol. 2014;5:1361. -1361. 11. Thaut MH. The discovery of human auditory-motor entrainment and its role in the development of neurologic music therapy. Prog Brain Res. 2015;217:253–266. 12. Roerdink M, Bank PJ, Peper CL, Beek PJ. Walking to the beat of different drums: practical implications for the use of acoustic rhythms in gait rehabilitation. Gait Posture. 2011;33(4):690–694.
ARTICLE IN PRESS A. Hernandez et al. / Heart & Lung 00 (2020) 1 5 13. Thaut MH. Music therapy, affect modification, and theraputic change: twords an intigrative model. Music Ther Perspect. 1989;7:55–62. 14. Crapo OR, Asaburi RC, Coates AL, et al. ATS Statement: Guidelines for the Six-Minute Walk Test. 2002. 15. American Thoracic Society. ATS statement: guidelines for the six-minute walk test. Am J Respir Crit Care Med. 2002;166:111–117. 16. Borg G. Psychophysical bases of percived exertion medicine and science in sports and exercise1982;14(5):337 381. 17. Parshall MB, Schwartzstein RM, Adams L, et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med. 2012;185(4):435–452. 18. Meek PM, Lareau S. Critical outcomes in pulmonary rehabilitation: assessment and evaluation of dyspnea and fatigue. J Rehabil Res Dev. 2003;40(5):13–24. 19. Kendrick KR, Baxi SC, Smith RM. Usefulness of the modified 0-10 borg scale in assessing the degree of dyspnea in patients with COPD and asthma. J Emerg Nurs. 2000;26(3):216–222. 20. Singh SJ, Puhan MA, Andrianopoulos V, et al. An official systematic review of the European Respiratory Society/American Thoracic Society: Measurement properties of field walking tests in chronic respiratory disease. Eur Respir J. 2014;44(6):1447–1478. 21. Leow LA, Rinchon C, Grahn J. Familiarity with music increases walking speed in rhythmic auditory cuing. Ann N Y Acad Sci. 2015;1337:53–61. 22. Holland AE, Nici L. The return of the minimum clinically important difference for 6-minute-walk distance in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2013;187(4):335–336. 23. Ho CF, Maa SH, Shyu YI, Lai YT, Hung TC, Chen HC. Effectiveness of paced walking to music at home for patients with COPD. COPD. 2012;9(5):447–457. 24. Alter DA, O’Sullivan M, Oh PI, et al. Synchronized personalized music audio-playlists to improve adherence to physical activity among patients participating in a structured exercise program: a proof-of-principle feasibility study. Sports Med Open. 2015;1(1):7. 25. Bronas UG, Everett S, Steffen A, et al. Rhythmic auditory music stimulation enhances walking distance in patients with claudication: a feasibility study. J Cardiopulm Rehabil Prev. 2017.
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26. Bauldoff GS. Music: more than just a melody. Chron Respir Dis. 2009;6(4):195–197. 27. Bauldoff GS, Hoffman LA, Zullo TG, Sciurba FC. Exercise maintenance following pulmonary rehabilitation*: effect of distractive stimuli. Chest. 2002;122(3):948–954. 28. Leow LA, Parrott T, Grahn JA. Individual differences in beat perception affect gait responses to low- and high-groove music. Front Hum Neurosci. 2014;8:811. 29. Karageorghis CI, Priest DL. Music in the exercise domain: a review and synthesis (Part I). Int Rev Sport Exerc Psychol. 2012;5(1):44–66. 30. Brody R. Music medicine. Omni. 1984;6:110–116. 31. Smoller JW PM, Ottto MW, Rosenbaum JF, Kradin RL. State of the art: Panic anxiety, dyspnea and respiratory disease. Am J Res Crit Care Med. 1996;154:6–17. 32. Gift AG MT, Soeken K. Relaxation to reduce dyspnea and anxiety in COPD patients. Nurs Res. 1992;41:242–246. 33. Renfroe KL. Effect of progressive relaxation on dyspnea and state anxiety in patients with chronic obstructive pulmonary disease. Heart Lung. 1988;17:408–413. 34. Tsai HF, Chen YR, Chung MH, et al. Effectiveness of music intervention in ameliorating cancer patients' anxiety, depression, pain, and fatigue: a meta-analysis. Cancer Nurs. 2014;37(6):E35–E50. 35. Bellieni C, Cioncoloni D, Mazzanti S, et al. Music provided through a portable media player (iPod) blunts pain during physical therapy. Pain Manag Nurs. 2013;14(4): e151–e155. 36. Aryal S, Diaz-Guzman E, Mannino DM. COPD and gender differences: an update. Transl Res. 2013;162(4):208–218. 37. Bea Lamprecht. Sex-related differences in respiratory symptoms: results from the bold study. Eur Res J. 2013:(42):858–886. 38. Camp PG, O'Donnell DE, Postma DS. Chronic obstructive pulmonary disease in men and women: myths and reality. Proc Am Thorac Soc. 2009;6(6):535–538. 39. Johnson JL, Campbell AC, Bowers M, Nichol AM. Understanding the social consequences of chronic obstructive pulmonary disease: the effects of stigma and gender. Proc Am Thorac Soc. 2007;4(8):680–682. 40. Watson L, Vestbo J, Postma DS, et al. Gender differences in the management and experience of chronic obstructive pulmonary disease. Respir Med. 2004;98 (12):1207–1213.