Brain Biomarkers of Response to Treatment for Apraxia of Speech

Study Overview
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Brief Summary
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The study will use MRI brain imaging to identify brain changes associated in stroke patients after they receive speech-language treatment for their speech difficulties.

Detailed Description
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The goals of the current study are to identify grey and white matter regions that are predictive of speech treatment response and measure neural plasticity in response to speech treatment, using state-of-the-art neuroimaging and statistical processing techniques in a group of well-characterized left hemisphere patients meeting strict inclusionary criteria. Specifically, the investigators will use voxel-based lesion symptom mapping to identify lesion sites most predictive of a positive response to speech treatment and advanced diffusion imaging techniques to map changes in the integrity of white matter tracts from pre- to post-treatment.

Official Title
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Brain Biomarkers of Response to Treatment for Apraxia of Speech

Conditions
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Aphasia, Stroke

Intervention / Treatment
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* Behavioral: Speech Production Treatment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Inclusion criteria are age 40-90 primary English speaker since < age 5 a history of a single left hemisphere stroke at least 1 year post-stroke at least 12 years of education pre-morbidly right-handed (Edinburgh Handedness Questionnaire) within normal limits on the Test of Non-Verbal Intelligence Exclusion Criteria: Exclusion criteria will include a pre-morbid neurologic or psychiatric history history/current substance abuse disorder MRI contraindications other motor speech disorders (e.g., dysarthria) current or recent (<2 months) speech/language therapy prior SPT pre-morbid history of speech/language disorders significant hearing disabilities (based on a pure-tone audiological screen at 35 dB HL at 500, 1K, and 2K Hz for at least one ear) aphasia severity resulting in <30th percentile performance on the Porch Index of Communicative Ability-R

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Speech Production Treatment<br>This treatment employs a response-contingent hierarchy made up of verbal modeling/repetition, graphic cueing, integral stimulation, and articulatory placement instruction. The investigators chose this treatment for the following reasons: 1) rigor of development demonstrated across multiple studies, 2) large and predictable effects with published, quantified effect sizes, 3) a demonstrated pattern of generalization to untrained items, illustrating experimental control, 4) an established multi-modal stimulation protocol, and 5) use of repeated practice, which is associated with neural plasticity. | Behavioral: Speech Production Treatment<br>* This treatment employs a response-contingent hierarchy made up of verbal modeling/repetition, graphic cueing, integral stimulation, and articulatory placement instruction.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Percent of Trained Items Correctly Repeated | For each participant, three target sounds were chosen: single consonants, vowels, or clusters at the word level. Based on these target sounds, 10 word items were generated for each target sound that served as Trained Items. Participants were tested on lists of Trained Items (probe trials) during repeated sessions in pre-intervention stage to establish baseline performance (percent of each word list repeated correctly) and during every other treatment session (again, percent of each word list repeated correctly). The change in percent correct list repetition from pre-intervention (5 probe trials) to the end of intervention (final 3 probe trials) was calculated as individual treatment effect sizes using the Busk & Serlin (1992) d2 statistic, which involves subtracting the difference between mean performance at end of the intervention minus pre-intervention, divided by the pooled standard deviation of the two phases. The larger the d2 effect size, the larger the effect of the treatment. | 8 weeks | 
| Change From Baseline in Percent of Untrained Items Correctly Repeated | To test generalization, we assessed the change in performance (percent correct repetition) on lists of 10 Untrained Items that had the same speech production targets as each patient's lists of 10 Trained Items, balanced for syllabic structure, word frequency, grammatical form class, and stress pattern. Just as for Trained Items, participants were tested on the lists of Untrained Items (probe trials) during repeated sessions in the pre-intervention stage to establish baseline performance and during every other treatment session (percent of each word list repeated correctly). The change in percent correct list repetition from pre-intervention (5 probe trials) to end of intervention (final 3 probe trials) was calculated as individual treatment effect sizes using the d2 statistic: the difference between mean performance at end of the intervention minus pre-intervention, divided by the pooled standard deviation. The larger the d2 effect size, the larger the effect of the treatment. | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage Change in Fractional Anisotropy (FA) | To measure neuroplasticity associated with the speech treatment protocol, the investigators calculated the percent change in fractional anisotropy (FA) from pre- to post-treatment for each of the eight fiber tracts in the left hemisphere. The average percentage change in FA across all eight fiber tracts was calculated, which could thus range from 0-100%. A positive change indicates an increase in white matter integrity, and a negative change indicates a decrease in white matter integrity. A number close to 0 indicates minimal/no significant change. | 8 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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aphasia, stroke, Magnetic Resonance Imaging, Diffusion Magnetic Resonance Imaging