NeuroRehabilitation 32 (2013) 185–190
DOI:10.3233/NRE-130835
IOS Press
185
Study of accent-based music speech protocol
development for improving voice problems
in stroke patients with mixed dysarthria
Soo Ji Kima,∗
and Uiri Job
aDepartment of Music Therapy, Graduate School and Ewha Music and Rehabilitation Center, Ewha Women’s
University, Seoul, Korea
bPrivate Practice, Seoul, Korea
Abstract. Based on the anatomical and functional commonality between singing and speech, various types of musical elements
have been employed in music therapy research for speech rehabilitation. This study was to develop an accent-based music speech
protocol to address voice problems of stroke patients with mixed dysarthria. Subjects were 6 stroke patients with mixed dysarthria
and they received individual music therapy sessions. Each session was conducted for 30 minutes and 12 sessions including pre- and
post-test were administered for each patient. For examining the protocol efﬁcacy, the measures of maximum phonation time (MPT),
fundamental frequency (F0), average intensity (dB), jitter, shimmer, noise to harmonics ratio (NHR), and diadochokinesis (DDK)
were compared between pre and post-test and analyzed with a paired sample t-test. The results showed that the measures of MPT, F0,
dB, and sequential motion rates (SMR) were signiﬁcantly increased after administering the protocol. Also, there were statistically
signiﬁcant differences in the measures of shimmer, and alternating motion rates (AMR) of the syllable /Ke/ between pre- and
post-test. The results indicated that the accent-based music speech protocol may improve speech motor coordination including
respiration, phonation, articulation, resonance, and prosody of patients with dysarthria. This suggests the possibility of utilizing the
music speech protocol to maximize immediate treatment effects in the course of a long-term treatment for patients with dysarthria.
Keywords: Accent-based, music-speech protocol development, mixed types of dysarthria, stroke patients
1. Introduction
Along with many complicated neurological problems
that stroke patients present,weakness, incoordination
or paralysis of the muscles involved in speech
production are common problems after the onset of
stroke (Mackenzie, 2011). A group of these speech
motor problems due to neurological impairments is
known as dysarthria (Duffy, 2005). Approximately
20–30% of stroke patients present dysarthria (Warlow,
∗Address for correspondence: Soo Ji Kim, Department of
Music Therapy, Graduate School and Ewha Music and Rehabilitation
Center, Ewha Women’s University 11-1 Daehyun-dong,
Seodaemun-gu, Seoul 120-750, Korea. Tel.: +82 2 3277 6916;
E-mail: specare@ewha.ac.kr.
Dennis, van Gijin et al., 2000), which is characterized
by slow, weak, and imprecise speech patterns with
uncoordinated movements of the speech musculature
(Kim, 2010). While the number of stroke patients with
dysarthria is relatively large, less attention has been
given to this byproduct of stroke than has been shown
to aphasia, an impairment of language.
Seven types of dysarthria are identiﬁed based on the
damaged brain region. These include ﬂaccid dysarthria,
spastic dysarthria, ataxic dysarthria, hypokinetic and
hyperkinetic dysarthria, unilateral upper motor neuron
(UUMN) dysarthria, and mixed dysarthria (Darley,
Aronson, & Brown, 1969; Duffy, 2005). Unilateral
brain damage causes unilateral upper motor neuron
dysarthria, showing imprecise articulation; while
1053-8135/13/$27.50 © 2013 – IOS Press and the authors. All rights reserved
186 S. J. Kim and U. Jo / Accent-based protocol for mixed dysarthria
bilateral brain damage is associated with spastic
dysarthria, indicating reduced loudness and strainedstrangled
voice with short breath support. Hypokinetic
and hyperkinetic dysarthria result when damage occurs
in the basal ganglion motor circuits. Ataxic dysarthria
is related to cerebellum damage, which results in the
breakdown of motor organization and control (Duffy,
2005; Kim, 2009). Mixed dysarthria, as the name
indicates, includes a mixture of two or more of any
dysarthria type. When more than one type of dysarthria
is present, the dominant type is determined by the location
of the damage (Darley et al., 1969; Duffy, 2005).
All of the above types of dysarthric speech include
dysfunctions in laryngeal movements, respiration,
articulation and swallowing (Baker, Ramig, Luschei,
& Smith, 1998; Nagaya, Kachi, Yamada, & Igata,
1998; Leopold & Kagel, 1997). Depending on the
damaged brain area, stroke patients with dysarthria
may present poor articulation, breathlessness, monotone
speech, or difﬁculties with intonation and rhythm
oftheirspeech.Somesymptomscontinueafterthecompletion
of rehabilitation; therefore, social interaction
and communication skills remain limited (Brady, Clark,
Dickson, Paton, & Barbour, 2011).
Since the 1970’s, various interventions have been
developed for dysarthria, yet no standardized approach
has been established (Sellars, Hughes, & Langhorne,
2002). The well-known Lee Silverman Voice Treatment
(LSVT) technique focused on increasing both
respiratory effort and vocal fold adduction (Ramig et
al., 1995), and other treatments increased subglottal
air pressure for increasing inspiratory and expiratory
volume (Hixon, 1973). Overall, however, patients
with dysarthria need direct assistance in altering vocal
quality.
An extensive body of research has demonstrated the
use of musical elements in enhancing speech functions
(Haneishi, 2001; Kim, 2010; Magee, Brumﬁtt, Freeman,
& Davidson, 2006; Tamplin, 2008). Additionally,
the relationship between music and speech production
has been investigated through brain research. Generally,
a portion of the brain known as Broca’s area,
in the posterior part of the inferior frontal gyrus, is
acknowledged to be involved in speech production, and
current research ﬁndings reveal that this area is activated
by various musical tasks as well, including pitch
and rhythm discrimination, pitch memory, and musical
syntax (Binder et al., 1997; Koelsch, et al., 2002; Maess
et al., 2001; Patel, 2003; Platel et al., 1997). Based
on the similarity of brain involvement and anatomical
structures between singing and speech production, it
may be expected that musical elements such as rhythm,
pitch, tempo, lyrics, and dynamics can be successfully
incorporated into speech rehabilitation.
Among these various musical elements, accent
not only changes musical quality inﬂuencing meter
perception (Robert & Mari, 2009), but also shapes
melody and rhythmic pattern in a musical and temporal
context (Boltz, 1993). In fact, accent is observed in
both music and speech. One voice therapy developed
using accent on vowel sounds is called Accent
Method (AM), and is used primarily for acoustical
improvement in speech production (Kotby, 1995). In
conjunction with body movement, AM can be used for
hyperfunctional and hypofunctional voice problems.
Three major principles of AM are 1) optimal abdominodiaphragmatic
breath support; 2) rhythmic play of
accentuated relaxed vowels intended to carryover
to speech, and 3) dynamic rhythmic body and arm
movements (Bassiouny, 1998). AM targets functional
exercises of respiration, phonation, and articulation,
which then are transferred to speech. Several studies
used AM to address varying degrees of voice problems
(Fex, Fex, Shiromoto, & Hirano, 1994; Simberg, Sala,
Tuomainen, Sellman, & Ronnemaa, 2006), yet voice
dysfunction due to neurological damages has not yet
been investigated. This might be due to the fact that
stroke patients typically demonstrate overall lowered
cognitive functions, including short attention span and
decreased short-term memory, coupled with a lack of
musical competency to keep a steady beat and utilize
melodic and rhythmic accents for speech therapists.
Previous music therapy literature has examined
musical elements in dysarthric speech to regulate the
speech motor function by providing rhythmic cues
and temporal and melodic alterations (Haneishi, 2001;
Pilon, McIntosh, & Thaut, 1998; Tamplin, 2008). Integration
of accent in music applications for dysarthric
speech such as singing and chanting may enhance
acoustical components of speech parameters, because
producing accentuated sound stimulates respiratory
controls and glottal attack. Based on these previous
ﬁndings and the advantages of accent, this study is to
investigate the Accent-based Music Speech Protocol
(AMSP) for acoustical components of speech including
Maximum Phonation Time (MPT), Fundamental
Frequency (F0), Decibel level (dB), Jitter and Shimmer,
Noise to Harmonic Ratio (NHR), Diadochokinetic
rate (DDK) in stroke patients with dysarthria. In
order to develop AMSP, previous speech protocols for
dysarthric speakers and the original version of AM were
reviewed.
S. J. Kim and U. Jo / Accent-based protocol for mixed dysarthria 187
2. Method
2.1. Subjects
Six stroke patients (mean age = 58.83) with mixed
dysarthria participated in this study. Due to the multiple
characteristics of mixed dysarthria, patients who
showed spastic components as the primary symptom
were included. All subjects are diagnosed as stroke
within one year prior to the study, and diagnosed as
stroke with mixed dysarthria. The neurologist and a
speech therapist conﬁrmed each subject’s dysarthria
type. Inclusion criteria were 1) no hearing and visual
difﬁculties, 2) age ranges between 50 to 65, and 3) completion
of written consent forms including video/audio
consent forms. Researchers verbally explained the
studyprotocolandansweredsubjects’questionsregarding
the information in the consent form to subjects
before they completed the forms. Subjects were
recruited at a rehabilitation medical center in Seoul. All
procedures of this study followed the research protocol
of the medical center. Each subject’s characteristics are
outlined in Table 1.
3. Data collection
Each subject’s voice was recorded using a microphone
(Logitech Desktop Microphone USB MIC)
and a computer software program, PRAAT (version
5.2; Boersma & Weenink, 2007). The same distance
between subjects’ mouths and the microphone was
maintained by providing test trials three times.
Voice recordings were performed with a laptop
computer with a Pentium processor and the Logitech
Desktop Microphone USB MIC. The microphone to
mouth distance was ﬁxed at 15 cm and the subject was
asked to phonate /a/ vowel at least 5 times at the most
comfortable level. Praat version 5.2, a computerized
speech software program, was used to analyze voice
recording samples.
Maximum phonation time (MPT) was determined
by measuring the duration of /a/ vowel produced at a
comfortable amplitude and pitch level of voice after
maximum inspiration. Following appropriate instructions,
the procedure was repeated three times by the
subject, and the recording with the longest duration was
considered as the MPT.
Fundamental frequency (F0) reﬂects the rate of vocal
fold vibration and closely matches our perception of
pitch. In speech, changes in F0 can reﬂect linguistic and
affective prosody. F0, dB, Jitter, Shimmer, and NHR
were estimated from the frequency and amplitude of
perturbation measurement.
Subjects were then asked to repeat the phonemes
/pe/, /te/, and /ke/ as rapidly as possible and as long as
possible at a comfortable pitch and loudness. This test
is used for the clinical assessment of motor function
of speech (Fimbel, Domingo, Lamoureux, & Beuter,
2005). DDK can be used as a measure of syllable timing
and rhythm in speech (Kent, Weismer, Kent, Vorperian,
& Duffy, 1999). Irregular syllable timing during DDK
is strongly associated with ataxic dysarthria and can
be associated with spastic dysarthria as well (Tjaden
& Watling, 2004). DDK measures are divided into two
types: alternating motion rate (AMR) and sequential
motion rate (SMR). AMR is measured as the rapid repetition
of a single syllable ( pe), and SMR is measured
as the rapid repetition of a sequence of syllables (/pe/,
/te/, /ke/).
4. AMSP protocols
Based on the AM method, the researchers integrated
musical elements into accentuated vocalization. The
AMSP protocol consisted of four stages (see Table 2
for comparison).
The ﬁrst stage was warm-up (4 minutes). Subjects
were asked to stretch both arms and move up and
down slowly. If subject is hemiplegic, he or she was
asked to hold the involved hand with the healthy hand.
Table 1
Subject characteristics
Subject Gender Age Dysarthria type On set MMSE-K Diagnosis
1 M 64 Mixed dysarthria 11/02/04 29 Quadriplegia secondary to Rt. PCA Lt. midbrain thalamic infarction
2 M 57 Mixed dysarthria 10/09/28 28 Lt. Hemiplegia d/t Rt. Pons infarction
3 M 52 Mixed dysarthria 11/02/06 29 Rt. Hemiplegia d/t Lt. Pons infarction
4 M 53 Mixed dysarthria 10/05/09 30 Quadriplegia secondary to pons„ medulla„ cerebellar infarction
5 F 62 Mixed dysarthria 10/09/30 26 Quadriplegia secondary to both cerebellar Rt. Brain stem infarction
6 F 65 Mixed dysarthria 11/01/20 23 Lt. Hemiplegia Rt. BG ICH
MMSE-K: Korean version of MMSE, Lt: Left, Rt: Right, BG: Basal Ganglia, ICH: Intra Cerebral Hemorrhage.
188 S. J. Kim and U. Jo / Accent-based protocol for mixed dysarthria
Table 2
Accent method vs. Accent-based music-speech protocol (AMSP)
Stages Accent method AMSP
Introduction Relaxation & voice rest Upper body stretching with music
Breathing exercise Breathing exercise Breathing exercise with a hand drum
Phonatory exercise 1) /f/v/s/z/ 1) /f/ as long as possible
2) /a ‘a:/, /i ‘i:/, /u ‘u:/ with largo tempo 2) /a/ with descending glissando
3) /a ‘a’a’a:/, /i ‘i’i’i:/, /u ‘u’u’u:/ with Andante
tempo
3) /a/e/i/o/u/ with singing
4) /a ‘a’a’a’a’a:/, /i ‘i’i’i’i’i:/, /u ‘u’u’u’u’u:/
with Allegro tempo
4) /a ‘a:/, /i ‘i:/, /u ‘u:/ vocalization = 50∼60,
three beats
5) /a ‘a’a’a:/, /i ‘i’i’i:/, /u ‘u’u’u:/ vocalization
= 70∼80, four beats
6) /a ‘a’a’a’a’a:/, /i ‘i’i’i’i’i:/, /u ‘u’u’u’u’u:/
vocalization = 90∼130, four beats
Transferring Reading, monologue, or dialogue Melodic chanting with accents
Trunk rotation and head movements were followed. All
movements were accompanied with steady and sedative
music with four beats.
The second stage was respiratory training (4 minutes).
Subjects were asked to breath in and out with their
hands on their abdomens following the researcher’s
demonstration. This stage was accompanied by a keyboard
scale played with ascending and descending
melody lines.
The third stage was vocalization (10 minutes). In this
stage, the researcher held a hand drum and played two
preparation beats, and then subjects vocalized /a/ pretending
to yawn. This exercise was to facilitate opening
the throat and relaxation of the muscles involved in
vocalization. Subjects were then asked to sing a simple
song with /a/, /e/, /i/, /o/, /u/, or combination of
two of them. After completion of singing with vowel
sounds, subjects were asked to vocalize the same vowel
sound two times in a row, accentuating the second
vowel (/a/ - >/a/:). The second accentuated vowel was
longer than the ﬁrst one. The researcher added more
vowels according to subjects’ physical conditions.
Lastly, melodic chant with accent was performed
(12 minutes). Six Korean traditional chanting repertoires
were selected. Subjects chanted with accents in
conjunction with hand drumming on every ﬁrst and
third beat. Various lyrics and numbers of syllables were
included.
5. Study procedures
All subjects received conventional therapies including
speech therapy. After the subject recruitment
was complete, a total of six stroke patients with
Table 3
Results of aerodynamic and acoustical data
Pre mean ± SD Post mean ± SD t p
MPT 7.4 ± 3.41 14.46 ± 7.80 −3.04 0.028*
F0 135.92 ± 32.12 159.49 ± 43.02 −4.34 0.007*
Intensity (dB) 59.60 ± 3.09 69.21 ± 2.88 −6.63 0.001*
Jitter 1.60 ± 1.80 0.66 ± 0.46 1.49 0.195
Shimmer 10.26 ± 5.15 7.27 ± 3.95 3.55 0.016∗
NHR 0.21 ± 0.24 0.07 ± 0.06 1.94 0.110
*P < 0.05
mixed dysarthria completed consent forms. Pretest for
aerodynamic and acoustical parameters was performed
in a quiet and isolated room. A total of 10 sessions with
AMSP was implemented daily for two weeks. Because
all subjects were in sub-acute care in a rehabilitation
medical center, the period of music therapy intervention
was limited. Upon the completion of 10 sessions
with ASMP, posttest was performed at the same place
where the pretest was done.
6. Results
Stroke patients with dysarthria received 10 AMSP
sessions and results of pre- and post test were analyzed
using paired t-test (p < 0.05). Regarding aerodynamic
and acoustic parameters, results showed statistical signiﬁcance
in MPT, F0, intensity (dB), and Shimmer, but
no signiﬁcant results were found in Jitter and NHR. An
important and signiﬁcant (p < 0.001) improvement of
intensity was found. Mean DDK rate showed improvement
compared to mean scores of pretest; however, the
difference did not reach statistical signiﬁcance for /pe/
and /te/. Signiﬁcance was revealed in /ke/, which is
related to jaw movement (see Tables 3 and 4).
S. J. Kim and U. Jo / Accent-based protocol for mixed dysarthria 189
Table 4
Results of DDK rate
Pre mean ± SD Post mean ± SD t p
/pe / 10.00 ± 2.73 16.50 ± 8.66 −1.89 0.117
/te/ 10.50 ± 3.28 15.16 ± 7.62 −2.24 0.075
/ke / 8.16 ± 4.35 14.16 ± 7.52 −3.35 0.020∗
/pe te ke/ 3.93 ± 1.60 5.48 ± 1.92 −4.04 0.010∗
*p < 0.05
7. Discussion
In the present study, AMSP was applied to stroke
patients with dysarthria to improve speech production
and oral-motor function of speech. Intentional accents
were integrated into steps of AMSP and hand drumming
was used to facilitate subjects’ accents. Compared
to the Accent Method used in speech therapy, AMSP
added melodic chanting with accents and utilized musical
cues for respiration control to maximize the efﬁcacy
of treatment.
Patients in this study presented difﬁculties in speech
breathing control due to the decreased respiratory functions,
and alteration of length of vowels or lyrics with
musical cues can directly inﬂuence an improvement in
intensity. Also, using accents in melodic chants may
facilitate laryngeal movement resulting in improved F0.
Overall, MPT can be increased with the improvement
of coordination ability in respiration and vocalization.
Producing intentional accents and accentuated
melodic chanting required regulated timing of inhaling
and exhaling as well as vocal fold adduction. When
subjects make an effort to accentuate as they produce
a sound, the sequence of voice initiation may occur
moreaccurately,includinginhalationandincreasedtension
of vocal folds which are important to produce
phonation.
No statistical signiﬁcance in Jitter and NHR was
found due to ceiling effects. Mean Jitter and Shimmer
values measured in pretest were numerically high
enough for dysarthric speech; however, overall mean
values were decreased after the completion of sessions.
Regarding voice quality, alteration of tempo and repetition
of an accentuated melodic chant may play a
role in regulating laryngeal and/or respiration muscles.
Despite of non-signiﬁcance in Jitter and NHR scores,
decreased mean scores may represent the improvement
of voice quality among subjects.
Improvements in articulation were observed manifested
by DDK rate changes. Melodic chant in
conjunction with accents requires relatively slow and
exaggerated movements in oral motor muscles and
structures; therefore mean scores of /ke/, which shows
jaw movement, is higher than /pe/, which shows lip
movement, and /te/, which shows tongue movement.
It is assumed that emphasizing accents on the lyrics
may lead to clear jaw movements while less attention
was paid on enunciation, which requires more clear
articulatory movements.
Considering the steps of AMSP, it was appropriate
to facilitate higher participation from stroke patients
because upper body relaxation is essential for speech
production among dysarthric speakers. Warm-up stages
and integration of upper extremity movements during
vocalization allowed patients to be prepared for
the vocalization, inducing proper tension in muscles
related to speech. Melodic chanting requires repetition
of longer phrases and frequent accents, and the warmup
and vocalization with accents encouraged patients
to maintain their attention on steps.
Despite the positive outcomes in this study, the
absence of a control group is a weakness of the study
design. During the recruitment period, stroke patients
with several types of dysarthria were volunteered for the
study participation; however, the protocol was implemented
to patients who met the inclusion criteria.
Clearly, additional investigations with stroke patients
having different dysarthria types as well as additional
measures are required to achieve progress on the issue
of how this music protocol improves speech functions.
Acknowledgments
The work was supported by the Ewha Global Top 5
Grant 2011 of Ewha Women’s University, Seoul, Korea.
Conﬂicts of interest
There are no conﬂicts of interest regarding this
research.
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