The Development of Evidence Based Music
Therapy with Disorders of Consciousness
Summary
Dissertation submitted for the degree of Doctor of Philosophy
Department of Communication and Psychology
Aalborg University, Denmark 2014
Julian O'Kelly
Supervisors
Associate Professor Wendy Magee
Professor Hanne Mette Ochsner Ridder
The Development of Evidence Based Music Therapy with Disorders
of Consciousness
Summary
This summary details a thesis comprising research undertaken within a large UK neurorehabilitation unit aimed at developing the evidence base for music therapy in the
assessment of those with Disorders of Consciousness (DOC). The thesis consists of three
peer reviewed papers with linking text incorporating background details, developing themes
and overall conclusions. The papers comprise a literature review, an audit of concurrent
music therapy and global assessment data, and a within-subjects neurophysiological and
behavioural study of healthy and DOC responses to music therapy and other auditory
stimuli. The summary will detail the background and theoretical framework for the study, and
in doing so outline Paper I: 'Music therapy with disorders of consciousness and
neuroscience: the need for dialogue' (O’Kelly & Magee 2013a)1, which will be followed by
summaries of the two research papers and overall conclusions in relation to the thesis
research questions.
Background
Neuro-rehabilitation is a dynamic process aimed at maximizing physical, psychological and
social functioning. Two frameworks underpin modern neuro-rehabilitation:
(i)
Evidence Based Medicine (EBM) - the judicious used of clinically and scientifically
derived evidence to guide treatment decisions (Sackett et al., 2007)
(ii)
Physical Rehabilitation Medicine (PRM) - an approach acknowledging the
interdependency of the individual with their environment, and value of
multidisciplinary input in meeting rehabilitative goals effectively (Stucki & Melvin,
2007).
DOC primarily comprise Vegetative States (VS) with retained sleep/wake cycles without
awareness, and Minimally Conscious States (MCS), where some form of awareness is
observed. The detection of consciousness is pivotal to the diagnosis of VS or MCS (Aspen
Neurobehavioral Conference Workgroup, 1996).
1
Please refer to online thesis reference section (pp. 74-88) for full references
The music therapy literature contains a range of ‘rationale building’ material supporting the
use of music therapy with DOC, based on practical, neurological, psychological and social
observations. The practice of music therapy with those with DOC is characterised by two
contrasting models in the literature:
(i) the Humanist/Music Centered model, advocating the existence of a ‘mind’ or ‘soul’
separate from the body in our conception of consciousness (e.g. Aldridge, Gustorff &
Hannlich, 1990; Gustorff, 1995; Gustorff, 2002).
(ii) the Behavioural/Pragmatic model where consciousness is defined by brain function,
and consequently DOC by the lack thereof (e.g. Baker & Tamplin, 2006; Boyle, 1994;
Boyle & Greer, 1984; Magee, 2005; Magee et al. 2013; O’Kelly & Magee 2013 a & b).
Most research in this field contains methodological weaknesses and an inconsistent use of
diagnostic terminology (O'Kelly & Magee, 2013a). However, modern brain scanning studies
are revealing a wide range of ways in which music affects physiological states, cognition and
mood in healthy individuals. Whilst it is unclear how music may affect such states and
processes for those with DOC, the evidence from both healthy and stroke studies suggests a
potential role for music therapy in enhancing attention and supporting neuroplasticity to
produce functional gains in vision, speech and cognition (e.g. Särkomo et al., 2008; Schlaug,
Maechina & Norton, 2008; Soto, Funes, Guzman-Garcia, Warbrick, Rotshtein, &
Humphreys, 2009).
The prominent model of consciousness within EBM and PRM views consciousness as
comprising:
(i) arousal function, or the ‘level’ of consciousness , which is required for
(ii) awareness, or the ‘contents’ of consciousness or the ability of the brain to process
sensory information (Giacino & Whyte, 2005).
Modern neuro-rehabilitation methods state that for consciousness to be present, individuals
must be awake, able to process internal and external stimuli, and able to demonstrate goal
directed behaviour (Giacino, 1997). However, there exists a debate on a range of issues
relating to assessment of DOC, chiefly:
(i) what level of awareness and functional capacity of the brain should be considered as
sufficient for consciousness
(ii) how reliable neuro-imaging data is in revealing 'covert' awareness not evident from
behavioural assessment
(iii) the functional capacity of those in VS in relation to auditory, language and pain
processing.
Research questions
The primary research question for this thesis is:
1. Can music therapy treatment effect physiological and behavioural changes suggesting
arousal and awareness to contribute to diagnosis in assessment of patients with DOC?
(Papers II and III)
In order to answer this question, the following sub-questions are addressed:
2. Specifically what do concurrent music therapy and multimodal assessments reveal about
DOC patients in relation to their responsiveness to auditory and musical stimuli? (Paper II)
3. What information will a combined behavioural and neuro-physiological examination of VS,
MCS and healthy individuals presented with different music therapy treatments reveal in
relation to:
a) the differing effects of the treatments within and between individuals
and diagnostic groups i.e., healthy volunteers, VS and MCS (Paper III)
b) DOC patients and their assessment through means of standardised behavioural
assessments alone? (Paper III)
These research questions are addressed in the following summaries of Paper's II and III.
Paper II: The complementary role of music therapy in the detection of awareness in
disorders of consciousness: An audit of concurrent SMART and MATADOC
assessments (O’Kelly & Magee, 2013b)
The aim of this study was to address research question two: 'Specifically what do concurrent
music therapy and global assessments reveal about DOC patients in relation to their
responsiveness to auditory and musical stimuli?' In doing so, it was hoped the study could
also add to the evidence base in relation to the main research question, i.e. whether music
therapy might affect behavioural changes which might contribute to the diagnosis of
awareness state.
The study used five years of archived patient records where patients had received
concurrent assessments with the multimodal 'Sensory Modality Assessment and
Rehabilitation Technique' (SMART) (Gill-Thwaites, 1997; Gill-Thwaites & Munday, 2004) and
the ‘Music Therapy Assessment Tool for Disorders of Consciousness’ or ’MATADOC’
(Magee et al., 2013), which focuses on patients’ behavioural responses to musical stimuli. A
total of 42 records were retrieved (25 male, 17 female), where assessments were conducted
within 4 weeks of each other (mean: 5.45 days, SD=9). Inclusion criteria comprised patients
aged 18–75 years, with complete SMART and MATADOC assessments undertaken within 4
weeks of each other during a 5 year period between January 2007 and January 2012.
Records were excluded where sections of the assessment hard copy were missing. In cases
where diagnostic outcome of either tool was unclear (n: 6), expert opinion was sought from a
music therapist or occupational therapist experienced in using and analysing the
assessment data for MATADOC and SMART. Data were analysed in SPSS (ver. 20) for
statistical analysis using descriptive statistics for central tendency, dispersion and
correlation.
Whilst the two tools produced a high level of agreement in diagnostic outcome (rs 0.8),
divergent diagnosis and weaker correlations between behavioural response items
highlighted contrasting sensitivities of the tools. For example, MATADOC displayed higher
sensitivity within auditory and visual domains relative to SMART, but SMART data indicated
higher sensitivity in the motor domain. In addition, the important contribution of musical
response items in MATADOC, and the tactile response item in SMART, highlighted that both
tools provide unique behavioural data predictive of awareness. The study supports the
recommendation of Giacino et al. (2002) that given contrasting strengths of assessment
tools and heterogeneity of the DOC responses to stimuli, combining these tools provides
complementary data contributing to a fuller understanding of a patient’s level of awareness.
Paper III: Neurophysiological and behavioural responses to music therapy in
vegetative and minimally conscious states (O’Kelly et al., 2013)
The second study was designed to address the primary research question 'Can music
therapy treatment effect physiological and behavioural changes suggesting arousal and
awareness to contribute to diagnosis in the assessment of patients with DOC?' In doing so
the study also aimed to address sub-questions: 'What information will a combined
behavioural and neurophysiological examination of VS, MCS and healthy individuals
presented with different music therapy treatments reveal in relation to a) the differing effects
of the range of techniques within and between individual and diagnostic groups and b) DOC
patients and their assessment through means of standardised behavioural assessments
alone?
The literature covering neurophysiological and behavioural assessment of DOC and normal
human neurophysiological responses to music was reviewed to contextualise this study. The
review indicated a number of useful measures such as heart rate variability (HRV),
electroencephalogram (EEG) recordings might be used to assess for indications of arousal,
attention and cognitive processes associated with awareness, particularly in relation to
auditory stimuli such as music. Thus a rationale for a multiple baseline within subjects study
to address the above questions was made, where EEG, heart rate (HR), heart rate variability
(HRV), respiration and behavioural responses contingent to music therapy and other
auditory stimuli were compared within individuals and between with healthy, VS and MCS
cohorts.
The study was undertaken with patients at the same unit as the first study, where
recruitment comprised 20 healthy subjects (13 female and 7 male), 12 patients diagnosed as
VS (6 female, 6 male) and 9 as MCS (5 male, 4 female). Following five minutes of baseline
silence (BLS), subjects were presented with procedures typically used in music therapy: live
preferred music (LM) and improvised music entrained to respiration (EI). They were also
presented with recordings of disliked music (DM), and white noise (WN). Stimuli were
presented in randomised order to control for order effects.
Post hoc ANOVA tests indicated a range of significant responses (p ≤ 0.05) across healthy
subjects corresponding to arousal and attention in response to LM, including concurrent
increases in respiration rate with globally enhanced EEG amplitude responses across brain
regions and frequency bandwidths delta, theta, alpha and beta (p ≤ 0.05). Responses were
most significant in right frontal and temporal regions.
Whilst physiological responses were heterogeneous across patient cohorts, mean frontal
midline theta (FMT) increased significantly for LM in half (n: 6) of cases where ANOVA's
were significant (p ≤ 0.05), and peaked significantly for LM in 4 MCS cases (44%). Frontal
alpha amplitude changed significantly in 3 VS and 4 MCS subjects (p = 0.05 - 0.0001), with
the latter contributing to the significant finding for frontal alpha across the MCS cohort [F(4,
1850.1) =36.5, p < 0.001] with a peak for LM [post hoc contrast F(1, 809) = 50.6, p < 0.001].
Furthermore, behavioural data showed a significantly increased blink rate for LM (p = 0.029)
within the VS cohort. Two VS cases are presented in Paper III with concurrent changes (p ≤
0.05) across measures indicative of discriminatory responses to both music therapy
procedures. A third MCS case study is presented highlighting how more sensitive selective
attention may distinguish MCS from VS.
Discussion
Paper II
The first study (Paper II) compared archived information on 42 patients’ behavioural
responses to musical stimuli in a music therapy assessment (MATADOC) and a wider range
of sensory stimuli in concurrent SMART records. It is first worth noting the high level of
diagnostic agreement between MATADOC and SMART (rs 0.80, p < 0.01, 2 tailed). This
indicates that behavioural assessment for awareness based on primarily musical stimuli is
able to produce a strong agreement with outcomes from SMART, a well-established,
multimodal assessment tool undertaken in ten sessions compared to MATADOC's four. This
is supported by the standardisation study by Magee et al., (2013) which reports 100%
diagnostic agreement with SMART from 21 records, under rigorous research conditions.
The range of statistical tests conducted upon MATADOC's 15 domain measures in relation
to diagnosis highlighted sensitive, discriminatory responses (i.e., with a correlation of rs ≥ 0.6
with diagnosis) in the 'behavioural responses to music', 'attention to task' domains. These
findings provide evidence from clinically derived data that music therapy can elicit unique
behavioural responses with diagnostic power in relation to the detection of awareness. In
addition, more sensitive responses were found in the MATADOC auditory and visual
domains compared to SMART 'consistent' response domains (auditory rs 0.79 compared to
SMART's rs of 0.38, and visual rs 0.79 compared to SMART rs of 0.55). These higher
correlations with diagnosis suggest the musical focus and use of more complex auditory
stimuli are more effective for discriminating awareness within the auditory domain, and may
have some form of synergistic effect to produce greater sensitivity within the visual domain.
Paper III: Healthy Data
There is a lack of normative or 'healthy' data available to guide clinicians and researchers
using receptive music therapy methods. Aside from addressing the thesis research
questions, study two (Paper III) provides a useful contribution to this field. The findings of
significant increases in respiration rate (RR) in relation to listening to LM are noteworthy. The
RR for all musical stimuli (LM, DM and EI), were compared to the tempo of the
accompanying music, to indicate no substantive unconscious 'entrainment' relationship
between RR and the tempo of music listened to. This finding indicates that these responses
are related to cortically mediated, emotional, or 'top down' processes, according to
Salimpoor et al. (2009), thus may provide a useful benchmark in comparing with patient
responses, where individuals are often unable to communicate verbally or non-verbally.
In relation to the literature on HR and HRV and music listening detailed in Paper III (p. 2-3),
this study provides little support for time or frequency domain measures providing consistent
benchmarks for healthy 'aware' responses to the music therapy methods used in the study.
However, whilst the ANOVA tests revealed no significant change across the healthy cohort,
ANOVAs conducted on segmented data at the within-subject level did reveal a range of
often divergent significant change. Thus, it appears that normal HR and HRV responses to
music therapy methods are idiosyncratic and divergent between individuals, yet often
significant at the within-subject level.
There is a growing understanding of neuroplasticity in neuro-rehabilitation, or how the brain
is capable of re-organisation and self-modification following neurological trauma (Johansson
& Grabowski, 1994; Mateer & Kerns, 2000; Stein, 2009). Listening to 'pleasant' and
preferred music has been shown to be effective in promoting neuroplasticity to meet
functional goals for those with acquired brain damage such as decreasing visual neglect
(Särkamo & Soto, 2012; Soto et al., 2009), and improving cognitive function (Särkamo et al.,
2010). The findings of significant globally enhanced post hoc EEG amplitude responses for
LM (p ≤ 0.05) across EEG bandwidths resonate with this literature. Furthermore, the EEG
data coupled with the RR increases observed for LM provides evidence from a normative
perspective for the utility of using this music therapy procedure to support arousal with DOC.
Paper III: Patient Data
The diagnosis of VS as defined by the Aspen Neurobehavioral Conference Workgroup
(1996), is “a condition in which awareness of self and the environment is presumed to be
absent and there is an inability to interact with others, although the capacity for spontaneous
or stimulus-induced arousal (i.e., wakefulness) is preserved”. Furthermore, the task force
stated that there should be 'no evidence of sustained, reproducible, purposeful, or voluntary
behavioural responses to visual, auditory, tactile, or noxious stimuli' and 'no evidence of
language comprehension or expression' (p. 8). In relation to the above DOC nosology the
findings of study two make interesting and thought provoking reading.
Across the VS cohort, significant increases in blink rate were observed for LM, accompanied
by half (n: 6) of VS patients displaying significant post hoc increases of EEG amplitude in the
theta frequency in the frontal midline region (FMT) and 3 for the alpha bandwidth in the
frontal region, with 2 subjects also displaying significant increases in RR for LM in a similar
fashion to the healthy cohort. In some cases these heightened responses for LM occurred
concurrently in individuals. These findings suggest that despite the heterogeneity of DOC
pathology, LM provides a powerful stimulus in relation to eliciting a range of unique
responses across VS and MCS cohorts, which is noteworthy in relation to studies with
healthy and other populations. For example, the literature on FMT points to activation of
hippocampal and anterior cingulate cortex regions involved in memory, motivation, decision
making, processing information, and attention in healthy individuals (Mitchell, McNaughton,
Flanagan, & Kirk, 2008). Blink rate is correlated positively with dopaminergic system activity,
arousal (Karson, Dykman & Paige 1990), attention (Abe et al., 2011; Irwin, 2011) and
creativity (Chermahini & Hommel, 2010).
Despite the lack of clear behavioural evidence of awareness, change in neurophysiological
measures occurring at peak levels in relation to the uniquely dynamic and multi layered
stimuli of LM suggests a form of selective attention was elicited in some cases. Whilst these
covert responses may not be considered as 'purposeful' in the behavioural sense, they were
significant post hoc, and sustained throughout the stimulus presentation. Furthermore, whilst
it is unclear whether heightened responses observed for LM and EI relate to the musical or
lyrical content of the stimuli, some form of language or music syntactical processing cannot
be ruled out.
Neuroimaging studies point to intact auditory (Laureys et al., 2000), emotional, verbal, (Schiff
et al., 2002), pain (Kassubek et al., 2003) and language processing (Coleman et al., 2007),
and 'cortical learning' (Kotchoubey et al., 2006) in VS. Several leading authorities stress that
these 'modular' responses may only represent isolated behaviours, evidencing a disconnect
between primary cortex, thalamus, multi-modal or limbic regions and higher order integrative
/associative cortices in correctly diagnosed VS (Boly et al., 2004; Laureys et al., 2002).
However, heightened responses noted for VS patients in the study occurred at significant
post hoc peak levels for LM and/or EI in some cases. As LM and EI are stimuli which may
stimulate language, memory and emotional processing in response to its lyrical and/or
musical content, it seems hard to conceive of these responses as merely 'isolated' or
modular responses. LM in particular may relate to historical events in one's personal life,
such as weddings and other significant life events. Given the unique relationship between
these responses and LM, they might relate beyond Damasio's (2010) 'primordial feelings' to
his conception of 'full consciousness', defined in terms of the involvement of biographical
knowledge (pp. 22-23). Furthermore Tulving (1993) stated that whereas consciousness
should denote the detection of basic sensory events, awareness involves the more
advanced interpretation and experience of these events. Using this conceptualisation, it is
hard to deny some of the VS subjects 'consciousness' if not awareness when observing
these findings.
It is noteworthy that less discrimination between music therapy conditions and WN
characterised pooled VS data in a manner resonating with the concept of 'hypoarousal',
where subjects are unable to distinguish relevant from irrelevant information (Heilman,
Schwartz, & Watson, 1978). Discrimination evidenced by heightened cortical activation in
fMRI studies to auditory stimuli with emotional relevance has also been considered a
defining feature of MCS (Laureys, Owen, & Schiff, 2004). Harnessing EEG technology
alongside music therapy assessment in this manner may provide complementary data for
clinicians to draw upon when assessing for awareness and prognostic indicators. Thus,
when coupled with the behavioural data, compelling, albeit pilot level, support is given for
music therapy promoting neurophysiological responses associated with both arousal and
awareness.
Limitations
Given the lack of understanding and empirical research in this area, the study is necessarily
of a pilot, exploratory nature. This is an important caveat in relation to the use of the term
‘significance’ in the thesis. The lack of known, appropriate, and singular measures of arousal
or awareness precluded the use of power calculations to determine the numbers of subjects
required for significance testing in its fullest sense, so type I and II errors cannot be ruled
out. Nonetheless, the study uses the largest numbers of subjects in research of its kind to
date. It should also be noted that the music featured in study two (in particular LM and DM)
comprised heterogeneous tempo, harmonic, rhythmic and lyrical content. The lack of
standardisation in this area may well have provided a confounding effect on the data, thus
explaining the divergent results, particularly in the physiological measures. However, it would
be antithetical to provide these musical items in standardised form, as this would possibly
obscure any elicitation of responses based on intact memory function. Finally, due to the
limited resources and time scale of this study, patients did not receive auditory brain stem
testing to exclude patients with hearing impairment, which may have provided a further
confounding element to the findings.
Conclusions
This thesis addresses the lack of empirical evidence supporting music therapy in the
assessment and treatment of those with DOC. The shared belief of 'humanist/music centred'
and 'behavioural pragmatic' clinicians that music therapy has powers to reach even the most
profoundly injured VS patients detailed in Paper I finds initial support in data from
assessment records in Paper II. In addition to the high levels of diagnostic agreement found
between music therapy and global assessments, the use of musical stimuli in the MATADOC
was found to elicit unique responses which might be missed in global assessments with less
focus on the auditory domain.
Through a comparison of a range of responses to music therapy found in both healthy and
patient cohorts, Paper III gives further empirical support for music therapy in this field.
The paper provides a comprehensive record of DOC patients’ responses to music therapy,
in varying states of arousal, with heterogeneous pathologies and drug regimes. Despite
these confounding elements, music therapy, in particular the live performance of preferred
music, produced significant increases in blink rate across the VS cohort, concurrently with
significant changes in neurophysiological measures in several cases. These findings
emphasise the need to appreciate the unique response profiles of each patient, be they
behaviourally diagnosed as VS or MCS.
Given our understanding of arousal in supporting awareness, and the positive effects of
music on neuroplasticity, a rationale is provided by these findings for exploring the use of
music therapy in DOC rehabilitation. Differences observed between VS and MCS subjects
also highlight the enhanced ability of MCS patients to discriminate between meaningful and
meaningless stimuli. The combination of music therapy with neurophysiological assessment
may offer a novel aid to detecting awareness, as measured by the patients’ discriminatory
cortical responses. This combination offers potential advantages to more invasive,
expensive assessments such as fMRI, which are not applicable to all patients. Furthermore
research exploring responses observed here for their prognostic value is indicated.
In summary, this thesis provides pilot level evidence that music therapy can contribute to
assessment with DOC through effecting behavioural and neurophysiological change
associated with arousal and awareness, which may also be of prognostic value. The findings
indicate the potential for harnessing responses to music therapy to improve clinical
outcomes through rehabilitation, which merits further investigation.