Investigating the Effects of Rhythm and Entrainment on Fluency in People With Aphasia
Phase: NA
Conditions: Aphasia, Apraxia of Speech
Sponsor: MGH Institute of Health Professions

 
 
 
 
 
Title: Investigating the Effects of Rhythm and Entrainment on Fluency in People With Aphasia 
NCT05248295 
Document date: 09/23/2024 
 
 

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I.  Background and Significance 
Aphasia is a language disorder, most commonly as a result of stroke, that can affect speaking, 
understanding what others say, reading, and writing. It is common, affecting an estimated 2 million 
people in the U.S. (National Aphasia Association). A common goal in aphasia therapy is to 
increase meaningful spoken output; especially in people with nonfluent subtypes of aphasia, this 
may be discussed in terms of improving speech fluency. Apraxia of speech (AOS) is a motor 
speech planning disorder that frequently co-occurs with nonfluent aphasia, and many treatment 
tasks simultaneously address both AOS and aphasia. Treatment of comorbid aphasia and AOS 
often focuses on common expressions and tailored sets of phrases in the hope of maximizing 
functional gains.  
 
While there are numerous approaches to promoting fluency in people with aphasia (PWA), one 
common technique is to ask the person to “say it with me.” Unison speech, also referred to as 
choral speech, is explicitly incorporated into several formal treatments for aphasia and/or AOS, 
including Oral Reading for Language in Aphasia (ORLA; Cherney et al., 1986), Melodic 
Intonation Therapy (MIT; Albert, et al., 1973; Norton et al., 2009), “integral stimulation” that has 
long been described in the AOS literature (Rosenbek & Wertz, 1972), and script training 
approaches such as AphasiaScriptsTM (Lee et al., 2009). Notably, unison production has proven 
effective not just for aphasia and AOS but also for stuttering (e.g., Kalinowski & Saltuklaroglu, 
2003; Kiefte & Armson, 2008). 
 
Although unison speaking is a component of many therapy approaches, the conditions under which 
it works best have not yet been established, and it remains unclear why it works. There is evidence 
that for PWA, being able to see the speaker’s mouth and benefit from audiovisual input, rather 
than audio input alone, results in improved spoken output, measured as more correctly produced, 
different words (Fridriksson et al., 2012). Fridriksson et al. (2012) compared audiovisual input 
(AV), audio-only input (AO), and spontaneous speech (SS) in 13 PWA and found that while output 
in the AO condition was superior to SS on average, it was not significantly better. In contrast, 
output in the AV condition was significantly better than in either AO or SS. The benefit conferred 
by the addition of visual information was attributed to the mirror neuron system, which has been 
purported to link observation of an action with its execution by the observer (Gallese et al., 1996).  
 
More recent evidence from our group, however, indicates that audio-only input can be quite 
effective at improving spoken output. Kershenbaum at al. (2017) compared solo repetition to 
unison repetition (hear a sentence and repeat it, compared to hear a sentence and repeat it in unison 
with the model) and found significant increases in % syllables correct in the unison condition. 
There were numerous differences between Fridriksson et al. (2012) and Kershenbaum et al. (2017), 
including task (reading vs. repetition), stimulus length (connected sentences vs. single sentences 
or phrases), and output measure (correctly produced words vs. % syllables correct), but one 
potentially critical difference was that while the first study used sentences with a conversational 
prosody, the second used sentences spoken metrically. Racette et al. (2006) documented better 
spoken output (% words correct) under an audio-only unison speech condition compared to solo 
repetition, using utterances with a typical, conversational prosody (in French), but saw even larger 
choral gains when the productions were sung, i.e., when they followed a metrical pattern. It seems 
that whether or not the model utterance is metrical is an important variable impacting the degree 

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to which PWA benefit from speaking in unison with a model, perhaps particularly when the co-
speaker’s mouth is not visible (i.e., audio-only conditions). 
 
In considering why and how unison speech improves fluency, an important question is how the 
participant’s production is temporally related to the model. In unison speech, the speaker knows 
the target utterances ahead of time (e.g., through memorization, repetition, or having the printed 
text) and can therefore align their productions very closely with the model, with mean between-
speaker asynchronies as low as 40-50 ms in some conditions. When two speakers attempt to speak 
synchronously (as opposed to one speaker aligning with a recording), there is an alternation 
between who “leads” in time (Cummins, 2003). Taken together, the very short between-speaker 
asynchronies and lack of a consistent “leader” suggest that speaking in synchrony is an active 
process, collaborative when it involves two active speakers, and entails prediction of what is 
coming next in the signal. It is not the case that one speaker is closely shadowing the other. 
Neurotypical speakers are able to generate precise speech timing predictions from their knowledge 
as fluent speakers of the language in question, a limited amount of data on how the conversation 
partner speaks, and an understanding of a shared goal, and use those predictions to guide their 
speaking, a complex motor action. This is entrainment: aligning a motor action with an external 
signal.  
 
None of the existing studies examining unison speaking in PWA have reported asynchronies 
between the participants’ productions and the model. Indeed, it seems that few, if any, of these 
studies time-locked the recording of participants’ productions to the stimulus. It therefore remains 
unknown whether PWA truly entrain their speech during unison productions, under what 
conditions they are able to do so, how this varies across individuals with aphasia, and whether true 
entrainment is needed in order for a unison benefit to be conferred. 
 
Metrical structures are built upon integer divisions of some unit, just as musical rhythms are built 
from notes of different values; when speech adheres to a metrical framework, syllables occur at a 
regular interval, or some integer multiple of that interval. In contrast, more typical conversational 
prosody is based on linguistic knowledge, particularly syntactic and prosodic knowledge. We 
propose a “two-route” model of speech planning, in which this planning can be accomplished in 
one of two ways: according to either a metrical or a linguistic framework, with the latter used to 
produce typical, conversational speech. Further, we suggest that aphasia may differentially affect 
these frameworks, such that PWA are a well-suited population with which to test the two-route 
claim. Individuals within the population may show deficits to one route, both routes, or neither. 
People with nonfluent aphasia are expected to be unable to use syntax and prosody to construct a 
fluent speech plan, while those with fluent aphasia will often be able to do so, resulting in varied 
performance across individuals with aphasia when attempting to use a linguistic framework to 
produce conversational prosodic timing. Concerning the metrical route, PWA frequently show 
unusual difficulty processing rhythm and timing information (Zipse et al., 2014). Individuals with 
this deficit should be prone to difficulty using a metrical framework to organize their speech. The 
proposed study will explore this two-route model by (1) evaluating whether PWA show true 
entrainment when speaking along to speech that adheres to either a metrical or a linguistic 
framework, indicating that they can make use of the framework to predict what comes next in the 

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signal (Aim1), and (2) test whether PWA benefit from a unison model with either a metrical or a 
linguistic framework (Aim 2). 
 
 
II.  Specific Aims 
 
The specific aims of this study are to: 
 
1. Determine how timing alignment of sentences spoken along with an auditory model is 
affected by metrical vs. conversational prosody, for people with aphasia and for typical 
speakers. Participants will attempt to speak in unison to an audio recording of two types 
of sentences: (1) sentences with regularly occurring stressed syllables (metrical) and (2) 
sentences spoken with a typical, conversational timing pattern (conversational).  
Prediction: PWA will show varied patterns of performance across these tasks. Successful 
entrainment with one timing framework will not necessarily be associated with successful 
entrainment to the other type. 
 
2. Determine whether people with aphasia benefit from attempting entrainment when the 
signal consists of (a) sentences produced with metrical prosody, and (b) sentences 
produced with conversational prosody. In a 2x2 design, sentences with metrical vs. 
conversational prosody will be produced in repetition vs. in unison with a model. The 
number of accurate syllables produced will be compared across repetition (imitation) and 
entrainment (prediction) to evaluate the effect of attempting entrainment.  
Prediction: PWAs will vary as to whether they benefit from entrainment to sentences with 
metrical or conversational prosody. Critically, those who benefit from entrainment with 
one type of prosody will not necessarily benefit from entrainment with the other type. 
 
 
III. Subject Selection 
 
One-hundred participants will be recruited for this study, including 40 with aphasia, 40 age-
matched controls, and up to 20 controls enrolled for the purposes of piloting and refining stimuli, 
as well as training study staff on data collection procedures. All participants must be between the 
ages of 18 and 80 and pass a hearing screening, demonstrating thresholds < 40 dB at 1 kHz, 2 kHz, 
and 4 kHz in at least one ear, tested in a quiet room. Hearing screens will be conducted by the PI, 
who is a licensed speech-language pathologist, or by a research assistant trained by the PI, after 
informed consent has been obtained. Given that the screening thresholds are quite liberal, it is not 
anticipated that many participants will be excluded from the study based on the hearing criterion.  
 
Control participants must exhibit native-speaker level fluency in American English and must not 
report any history of speech or language disorders, stroke, or other neurological disease. They must 
repeat both sentences in the short form of the Sentence Repetition subtest of the Boston Diagnostic 
Aphasia Examination (BDAE; Goodglass, Kaplan, & Barresi, 2001) without any errors, given a 
maximum of 2 attempts per sentence. They must also pass the Mini-Cog screening (Borson et al., 
2000), a short cognitive screening measure that has been validated in older Americans to have 

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similar sensitivity and specificity for dementia as the Mini-Mental Status Exam. It consists of 
memory and recall of a list of three unrelated words after a filled interval of a clock drawing task. 
To be considered negative for cognitive impairment, participants have to either recall all three 
words or have a normal clock drawing if they only recall one or two words (Borson et al., 2003). 
 
PWA must be at least 6 months post-onset of aphasia and report pre-morbid native-speaker level 
fluency in American English, supported by report of other relevant information (e.g., age at which 
the individual began speaking English and extent they used it in daily life). They must score > the 
15th percentile, averaged across the 3 auditory comprehension subtests of the BDAE (Word 
Identification, Following Commands, Complex Ideational Material), and correctly repeat >50% of 
words on the Single Word Repetition subtest of the BDAE. In addition, they must score within 
normal limits on at least 3 of the 5 nonverbal subtests of the Cognitive-Linguistic Quick Test 
(CLQT; Helm-Estabrooks, 2001). 
 
Participants with aphasia will be recruited from the MGH IHP Aphasia Center, through RSVP for 
Health, through the Partners Research Portal website, the National Aphasia Association (NAA) 
website, and via an MGH-IHP IRB-approved Recruitment Database (IRB Protocol 2014P001166). 
At the MGH IHP Aphasia Center, information about the study will be briefly described and 
presented in written form as handouts at an aphasia group meeting at the MGH IHP Aphasia Center 
by the PI or a graduate student research assistant. All those interested in participating will be put 
in touch with the PI via email and phone. In addition, potential participants will be identified 
through the Research Patient Data Registry (RPDR) and sent a Research Invitation informing them 
about the study. Research Invitations will either be sent through the EPIC Patient Navigator system 
or through USPS. Study staff will check to ensure that patients have not opted out of receiving 
such invitations. If the research team does not receive a response, a call may be made to the 
potential participant 2 weeks after the letter has been sent. Control participants will be recruited 
via RSVP for Health, the Partners Research Portal website, the MGH-IHP IRB-approved 
Recruitment Database referenced above, flyers posted at the MGH IHP, and announcements 
seeking participants sent through Broadcast MGH and the IHP Daily News emails. Information 
about this research study will also be posted on the Institute’s website. (Note that ad language for 
controls includes a version for “healthy adults” and a version for “healthy adults aged 50-80.” In 
our experience, more general ads tend to attract mostly people <30, and people >50 are needed to 
age-match to the people with aphasia.) Control participants will be pre-screened by phone to 
confirm that they have native-level fluency in American English and do not have a history of 
speech or language disorders. 
 
Recruitment materials include an email address for the convenience of participants. Email will be 
used to establish contact, i.e., send study information in response to an initial contact from a 
potential participant (see “standard email response” documents), and to send appointment 
information and directions to the study site. Email will not be used to ask screening questions to 
determine eligibility. The warning language concerning secure vs. unencrypted email, as required 
by Partners, is included in the standard email response, along with a statement that additional 
communications will be sent securely unless the person requests otherwise and acknowledges the 
associated risks. If a potential participant with aphasia responds without acknowledging their 
acceptance of risks, they will receive a response requesting a phone number to communicate 
further, since sending future emails with the “send secure” requirements may be difficult and 

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confusing for a person with aphasia. Email contact is especially helpful to communicate with 
people with aphasia, many of whom have great difficulty on the phone but may have more success 
with email due to the reduced time pressure when formulating their thoughts, and the ability to 
read and re-read a message. Even if a follow-up call is required for security compliance, having 
the initial email that the person can refer to during the call may be very helpful, especially for 
scheduling purposes (e.g., choosing dates and times for people who may mix up numbers; seeing 
the same information printed while they are hearing it can be very helpful).  
 
 
IV.  Subject Enrollment 
 
Informed consent will be obtained at the start of the first (in many cases, only) study visit. This 
will be done at the MGH IHP, either in a clinic room within the Aphasia Center, or in an 
assessment room in the research building (for control participants). Informed consent will be 
obtained from each participant with aphasia by the PI or another study staff member who is a 
licensed speech-language pathologist with expertise in aphasia. For control participants, 
informed consent will be obtained by the PI or a research assistant trained by the PI for this 
purpose. For participants with aphasia, care will be taken to ensure that each person understands 
the nature of the study and has adequate time to ask questions and consider whether to 
participate. Study staff obtaining consent will make use of appropriate techniques to ensure good 
communication with a person with aphasia, including use of gesture, writing down or 
underlining key words, slow rate of speech, and adequate pauses to allow for processing time. 
Authorized study staff will verbally summarize the study procedures and the risks and benefits, 
and will make it clear that participation is voluntary and the participant can choose to discontinue 
the study at any time. Study staff will offer to read the consent form to the potential participant, 
in case the participant has difficulty reading due to aphasia. Finally, the authorized study staff 
member will ask the potential participant if he or she has any questions or concerns, allow time 
for a response, and clarify whether the person would like to participate before obtaining the 
participant’s signature. Clients with aphasia who meet the study criteria and choose to enroll in 
the study will participate in the study at the MGH IHP Aphasia Center, likely on the same day as 
their regular treatment session to minimize extra travel or effort on the part of the participant. 
Control participants will be asked to come to the MGH IHP at a mutually agreed-upon time. For 
controls, participation will require 1-2 visits totaling about 3 hours. For PWA, participation will 
require 2 study visits totaling about 4 hours. For PWA with existing diagnostic assessment data, 
the total time needed will be about 3 hours, which can be completed in 1 or 2 visits. Controls will 
be compensated $50 for participation, and PWA will be compensated $75. If any participant does 
not pass the pre-screening, they will be paid $30. 
 
 
V.  Study Procedures 
 
Tasks Administered to Characterize Participants 
 
The following assessments will be administered to participants with aphasia (PWA) to confirm 
eligibility for inclusion in this study: 

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• Hearing screen (pure tones at 1 kHz, 2kHz, 4kHz) 
• Long forms of the Single Word Repetition subtest and the 3 auditory comprehension 
subtests (Word Identification, Following Commands, Complex Ideational Material) of the 
BDAE  
• Nonverbal subtests of the Cognitive-Linguistic Quick Test (CLQT; Helm-Estabrooks, 
2001; Symbol Search, Symbol Trails, Design Memory, Mazes, Design Generation) 
 
The following assessments will be administered to control participants to confirm eligibility for 
inclusion in this study: 
 
• Hearing screen (pure tones at 1 kHz, 2kHz, 4kHz) 
• Short form of the Sentence Repetition subtest of the BDAE 
• Mini-Cog screening (Borson et al., 2000) 
 
In addition to the assessments needed to evaluate whether they meet inclusion criteria, PWA will 
complete the assessments listed below to characterize aphasia subtype and evaluate fluency, 
agrammatism, and apraxia of speech (AOS). In cases where Aphasia Center clients have completed 
these assessments within the past year, scores will be obtained from their clinical file to reduce 
unnecessary repetition of assessments. 
 
• Sentence Repetition (short form) and Picture Description subtests of the BDAE 
• One additional picture description, in order to compute Correct Information Units (CIUs) 
per second as a primary measure of fluency, and syllables/sec and % CIUs as secondary 
measures (Nicholas & Brookshire, 1993) 
• Boston Naming Test, 2nd edition, short form (BNT-2; Kaplan, Goodglass, & Weintraub, 
2000) 
• BDAE subtests for extended testing of syntactic processing: Touching A with B, Reversible 
Possessives, Embedded Sentences 
• Select subtests of the Apraxia Battery for Adults, 2nd edition (ABA-2): Diadochokinesis, 
Increasing Word Length 2A, Limb Apraxia, Oral Apraxia, Repeated Trials  
 
All participants will complete the following tasks in order to evaluate and quantify their nonverbal 
working memory capacity: 
• Corsi blocks: a visuospatial memory span task, requiring participants to observe the 
investigator point to a sequence of blocks and then repeat the sequence 
• Test of Everyday Attention (TEA), Elevator Counting with Distraction: an auditory 
selective attention task, requiring participants to listen to sequences of tones, counting the 
lower-pitched tones while ignoring the higher-pitched distractor tones 
 
All participants will complete the following task in order to evaluate and quantify their musical 
entrainment ability:  
 

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• Tapping to music portion of the Beat Alignment Test (BAT; Iversen & Patel, 2008): to 
evaluate ability to entrain to a musical beat 
 
Experimental Task Design 
 
To address the aims, a 2x2 design will be used to 
compare the performance of controls and PWA 
across 4 conditions, which will collectively evaluate 
performance with metrical vs. linguistic timing 
frameworks both when repeating (solo production) 
and when attempting to speak in unison (unison 
condition) (Fig 1). Each condition will follow a 
unison repetition task format: the participant 
hears the stimulus followed by an alerting tone, 
and then a repetition of the stimulus, to which the participant attempts to speak along.  
 
To address Aim 2, two solo repetition conditions, one with metrical sentences and one with 
conversational sentences, will be included in the task. In these conditions, the participant will hear 
the stimulus followed by an alerting tone, and then repeat the stimulus. Performance on these 
conditions will be compared to performance on the corresponding unison repetition conditions.  
 
Additional blocks of trials will allow for follow-up exploratory analyses of the role of self-
monitoring one’s own auditory feedback, as this has been implicated in speech accuracy in fluency 
in PWA (Jacks & Haley, 2015; Maas et al., 2015), and self-monitoring ability may be reduced 
during the unison conditions. In these additional trials, words and sentences will be repeated solo, 
either with or without masking noise. For the masked trials, masking noise (pink noise, which 
covers the speech frequencies) will be played through the headphones while the participant speaks, 
to interfere with their ability to hear their own productions. 
 
Experimental Stimuli 
 
The experimental task is comprised of 4 conditions: metrical sentence unison, conversational 
sentence unison, metrical sentence solo, and conversational sentence solo. Stimuli for all 
conditions will be matched for number of syllables and overall stimulus duration. and balanced 
across timing conditions for syntactic (e.g., wh- questions, compound subjects) and phonemic 
(numbers of fricatives, affricates, and clusters) complexity. 
 
To enable controlled analysis of entrainment across metrical vs. conversational sentence 
conditions (Aim 1), these sentences will be developed in pairs. Each pair will have the same 
number of syllables and the same target words. The same acoustic landmarks within these words 
will be used for analysis (Fig. 2).  
Fig. 1: Four conditions presented 

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For the exploratory trials aimed at investigating the role of self-monitoring one’s own auditory 
feedback when speaking, there will be a total of 60 multi-syllabic words across 4 blocks, half with 
masking noise and half without. There will also be a total of 60 sentences (adapted from the 
Harvard sentences corpus (IEEE Audio and Electroacoustics Group, 1969) across 6 blocks, 
including 2 blocks with masking noise, and 4 without (2 prior to any masking noise, and 2 
following the masked blocks).  
 
Experimental Task 
In order to ensure that task expectations are clear and to minimize the need for verbal cues and 
reiterating instructions (i.e., to minimize language comprehension demands for the PWA), the 4 
conditions will be presented in blocks, with condition-specific instructions and 2 practice items at 
the start of each block. Within a block, each trial will proceed as follows: the participant will hear 
the stimulus item, followed by an orienting tone, and then a repetition of the stimulus. In unison 
conditions, the stimulus will be re-played during the participant’s turn, so that the participant 
produces the stimulus in unison with the recording. In solo conditions, the stimulus will not be re-
played, so that the participant repeats the stimulus alone. Gestural cues along with verbal prompts 
will be used as needed with the practice items to cue participants to “wait their turn” (“stop” 
gesture) and “speak along” (hand extended to indicate “your turn”). During presentation of 
experimental items, gestural cues will continue to be used as needed; this approach has been used 
with success with PWA on a similar task (Kershenbaum et al., 2017).  
 
Data collection 
Stimuli will be presented and participant productions recorded using a laptop running Audacity 
software (https://audacityteam.org/). Stimuli will be played to the participant via adjustable, over-
the-ear headphones set to a comfortable listening level. The experimenter will be able to monitor 
what the participant hears via a single earphone connected to the audio output via a splitter. A 
headset microphone (Shure WH20XLR Dynamic Headset Microphone) connected to a laptop via 
an audio interface (Focusrite Scarlett 2i2 multichannel sound card) will be used to obtain all speech 
recordings. With this arrangement, stimuli and responses are separately recorded on two time-
locked channels. At the start of each recording session, line delays will be tested and noted for 
adjustment during analysis; this entails playing an abrupt stimulus (brief acoustic click) through 
the headphones into the microphone, and recording the presentation-to-recording delay in 
Audacity. A directional microphone (Shure SM58S Vocal Microphone) will be used to record 
tapping to music.  
 
 
VI. Biostatistical Analysis 
 
Aim 1: Determine how timing alignment of sentences spoken along with an auditory model is 
affected by metrical vs. conversational prosody, for people with aphasia and for typical speakers. 
Fig. 2: An example of a 9-syllable sentence 
pair. Target words are underlined, and 
stressed syllables are in bold italics. In 
metrical sentences, stressed syllables occur 
at regular intervals. 

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Audio files of stimuli and responses produced in the unison conditions will be labeled using a 
partially automated approach to extract the moment of voicing onset for vowels in target syllables 
(refer to Fig. 2). First, time intervals surrounding each syllable onset will be hand labeled using 
Praat Software (Boersma & Weenink, 2016). Second, the Praat autoVOT plugin (Keshet et al., 
2014) will be used to efficiently extract the timing of voicing onset (fig. 4). The autoVOT plugin 
has been demonstrated to perform comparably to manual annotation (Buz et al., 2018) and was 
judged reliable in an initial sample of our own data.   
 
 
 
Voice onset moment time points will be used to calculate the timing offset between participant 
productions and the corresponding time points in the stimuli. The line delay documented at the 
beginning of each participant’s experimental session will subtracted from each extracted timepoint 
from participant productions, and the stimulus timepoint will then be subtracted from that 
difference, calculated as 
 
 
(𝑝 − 𝑑) − 𝑠  
 
where p represents participant voice onset moment, d represents line delay, and s represents 
stimulus voice onset moment. The resulting value represents whether and how far productions 
occur before or after a stimulus. 
 
For statistical analysis, separate mixed-effects linear models will be run for controls and PWAs, 
with signed timing offset for each target syllable as the outcome.  
 
Aim 2: Determine whether people with aphasia benefit from attempting entrainment when the 
signal consists of (a) sentences produced with metrical prosody, and (b) sentences produced with 
conversational prosody. 
 
All sentences used to address Aim 2 will be transcribed and scored for syllable-level accuracy, 
according to a previously established, comprehensive set of rules (Kershenbaum et al., 2017). 
Twenty percent of utterances, distributed across PWA, will be independently transcribed and 
scored by a second rater to evaluate inter-rater reliability. 
 
A 2x2 ANOVA will be used to evaluate the relative benefit of entrainment on % of syllables 
correct for speech with conversational vs. metrical prosody. Exploratory follow-up correlations 
will evaluate any possible relationship between a “metrical benefit” and other participant 
Fig. 4: Example of autoVOT 
labeling procedure. The blue 
shaded 
region 
indicates 
the 
manually labeled search window 
that is input to the autoVOT 
program. The red line shows the 
voice onset moment identified by 
the autoVOT.  
 

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characteristics including fluency (from the picture description task), AOS severity, and 
entrainment ability (from the tap to a metronome, entrain a syllable to a metronome, and tap to 
music tasks). 
 
Power Analysis 
 
Aim 1: The data from this study will be used to establish effect sizes to enable a meaningful power 
analysis in an external grant application; there are currently no studies of which we are aware 
comparing time-locked measures of speech entrainment across PWA and controls. To try to ensure 
that the study is adequately powered, even if some of the PWA are unable to produce all of the 
target words/syllables or if the target landmarks are not identifiable, we have included a rather 
large number of target landmarks (4-16 labeled landmarks per stimulus, and 8 stimuli/condition, 
yielding ~80 data points/condition for each participant). 
 
Aim 2: Based on previous work from our group (Kershenbaum et al., 2017), the effect size of 
attempted speech entrainment is 0.975 (Cohen’s d). This is based on % of accurate syllables 
produced by PWA, compared across 2 conditions: attempting to entrain to spoken sentences versus 
repeating them solo. In that study, the spoken stimuli were metrical, with regular, predictable 
timing. We anticipate that sentences with conversational prosody may result in less of an 
entrainment gain for many PWA. Therefore, we used 0.7 as an estimated effect size, an alpha level 
of 0.05, and 0.90 for power. With these constraints, the needed sample size is 19 PWA (sample 
size analysis conducted with G*Power; Faul et al., 2007). Our proposed sample size of 25 allows 
for some participant attrition, data loss, or unscorable data (e.g., PWA who cannot produce enough 
scorable tokens). 
 
 
VII.  Risks and Discomforts 
 
For people with aphasia, there is a risk that the experimental tasks may be difficult and frustrating 
to complete. 
 
There is also a risk that participant privacy could be compromised in some way. Study data, 
including audio recordings of participants and calculated results will be maintained on encrypted 
Partners computers. Any paper records will be kept in a file drawer in a locked office at the MGH 
Institute. 
 
 
VIII.  Potential Benefits 
 
This study will not benefit participants directly. Rather, there are potential benefits to society, in 
that information learned in this study may be used to inform the development of more targeted and 
efficient aphasia therapy approaches. 
 
 

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IX.  Monitoring and Quality Assurance 
 
The PI will review the data after each testing session. Scoring may be completed by research 
assistants. In this case, the PI will initially review their scoring to ensure that it is done correctly. 
Syllable accuracy will be double-scored by another rater for at least 10% of the recorded samples, 
randomly selected across participants and conditions. A minimum intra-class correlation of 0.80 
will be required for the ratings to be considered reliable. 
 
X.  References 
 
Albert, M.L., Sparks, R.W., & Helm, N.A. (1973). Melodic intonation therapy for aphasia. 
Archives of Neurology, 29(2), 130-131. 
 
Boersma, Paul & Weenink, David (2016). Praat: doing phonetics by computer [Computer 
program]. Version 6.0.21, http://www.praat.org/ 
 
Borson, S., Scanlan, J., Brush, M., Vitaliano, P., Dokmak, A. (2000). The mini-cog: A cognitive 
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