Rosalind Hurwitz

Epidural cortical stimulation and aphasia therapy

Background: There are several methods of delivering cortical brain stimulation to modulate cortical excitability, and interest in their application as an adjuvant strategy in aphasia rehabilitation after stroke is growing. Epidural cortical stimulation, although more invasive than other methods, permits high-frequency stimulation of high spatial specificity to targeted neuronal populations. Aims: First we review evidence supporting the use of epidural cortical stimulation for upper limb recovery after focal cortical injury in both animal models and human stroke survivors. These data provide the empirical and theoretical platform underlying the use of epidural cortical stimulation in aphasia. Second, we summarise evidence for the application of epidural cortical stimulation in aphasia. We describe the procedures and primary outcomes of a safety and feasibility study (Cherney, Erickson, & Small, 2010), and provide previously unpublished data regarding secondary behavioural outcomes from that study. Main Contribution: In a controlled study comparing epidural cortical stimulation plus language treatment (CS/LT) to language treatment alone (LT), eight stroke survivors with nonfluent aphasia received intensive language therapy for 6 weeks. Four of these participants also underwent surgical implantation of an epidural stimulation device, which was activated only during therapy sessions. Behavioural data were collected before treatment, immediately after treatment, and at 6 and 12 weeks following the end of treatment. The effect size for the primary outcome measure, the Western Aphasia Battery Aphasia Quotient, was benchmarked as moderate from baseline to immediately post-treatment, and large from baseline to the 12-week follow-up. Similarly, effect sizes obtained at the 12-week follow-up for the Boston Naming Test, the Communicative Effectiveness Index, and for correct information units on a picture description task were greater than those obtained immediately post treatment. When effect sizes were compared for individual participant pairs on discourse measures of content and rate, effects were typically larger for the investigational participants receiving CS/LT than for the control participants receiving LT alone. These analyses support previous findings regarding therapeutic efficacy of CS/LT compared to LT, i.e., epidural stimulation of ipsilesional premotor cortex may augment behavioural speech-language therapy, with the largest effects after completion of therapy. Conclusions: Continued investigation of epidural cortical stimulation in combination with language training in post-stroke aphasia should proceed cautiously. Carefully planned studies that customize procedures to individual profiles are warranted. Information from research on non-invasive methods of CS/LT may also inform future studies of epidural cortical stimulation.

Transcranial direct current stimulation and aphasia: the case of mr. C.

Abstract Purpose: To illustrate the ethical challenges that arose from investigating a novel treatment procedure, transcranial direct current stimulation (tDCS), in a research participant with aphasia. Method: We review the current evidence supporting the use of tDCS in aphasia research, highlighting methodological gaps in our knowledge of tDCS. Then, we examine the case of Mr. C, a person with chronic aphasia who participated in a research protocol investigating the impact of tDCS on aphasia treatment. We describe the procedures that he underwent and the resulting behavioral and neurophysiological outcomes. Finally, we share the steps that were taken to balance beneficence and nonmaleficence and to ensure Mr. C’s autonomy. Results: The objective data show that while Mr. C may not have benefitted from participating in the research, neither did he experience any harm. Conclusion: Researchers must consider not only the scientific integrity of their studies, but also potential ethical issues and consequences to the research participants.

Validity, reliability and sensitivity of the NORLA-6: Naming and oral reading for language in aphasia 6-point scale

Abstract Purpose: Evaluation of the Naming and Oral Reading for Language in Aphasia 6-point scale (NORLA-6), a scoring system of oral reading and naming performance in aphasia. Method: Data were drawn from 91 participants with non-fluent aphasia secondary to left-hemisphere stroke across four treatment studies. To assess validity, Spearman’s correlations were calculated between the NORLA-6 and the Gray Oral Reading Test-Fourth Edition (GORT-4) Accuracy score, GORT-4 Rate score and the Boston Naming Test (BNT). Inter-rater and test–retest reliability were evaluated using correlations. Sensitivity to change following oral reading intervention was analysed using Wilcoxon Signed Rank tests between pre- and post-treatment NORLA-6 scores. Result: NORLA-6 performance was significantly correlated (p < 0.001) with all reference tests (GORT-4 Accuracy, rs=0.84; GORT-4 Rate, rs= 0.61; and BNT, rs= 0.92). Inter-rater (ICC ≥0.90) and test–retest (r > 0.92) reliability were both excellent. Sensitivity following oral reading intervention was demonstrated in both oral reading accuracy and rate (p < 0.004). Conclusion: The NORLA-6 is a valid and reliable measure of oral reading and naming performance. It also demonstrates sensitivity to change in treatment-targeted behaviours. Therefore, the NORLA-6 scale may enhance outcome measurement in both clinical practice and aphasia research.

Evaluating the impact of practice conditions (randomized vs. blocked) and schedule (distributed vs. massed) on script training in aphasia

Background: A growing body of evidence suggests that intensity of therapy is a critical factor influencing outcomes in aphasia treatment regardless of the treatment approach. However, little information is available regarding scheduling or practice conditions that optimize treatment outcomes. Much of the literature on practice and schedule conditions has come from well-established principles of motor learning. The extent to which these principles apply to aphasia, and to tasks that include not just motor skill learning but also complex language learning, requires investigation. Aims: The purpose of this study was to assess the impact of practice conditions (random vs. blocked) and schedule (distributed vs. massed) on script training in aphasia. Methods & Procedures: Thirty-six participants with aphasia (22 males; 14 females; 24 nonfluent; 12 fluent) were randomly assigned to one of four conditions that varied by practice (blocked vs. random) and schedule (massed vs. distributed). Overall, mean age was 58.57 (SD = 16.83) years; mean time post onset was 35.8 (SD = 35.9) months; mean education was 15.8 (SD = 2.6) years; and mean Western Aphasia Battery-Revised Aphasia Quotient was 62.96 (SD = 14.20). The treatment used was script training, administered via a computer program called AphasiaScripts that has demonstrated positive outcomes across several studies (Cherney, Halper, & Kaye, 2011; Cherney, Halper, Holland, & Cole, 2008; Cherney, Kaye, & Van Vuuren, 2014). To ensure consistency across subjects and across arms, standard scripts were used. The complexity of the scripts was set relative to the participant’s language level using methods successfully developed and previously reported (Kaye & Cherney, 2016). All participants received 18 h of script training on 12 different days (i.e. 3 × 30-min treatment sessions for a total of 90 min on each designated treatment day). Those randomized to the massed schedule arm completed the 18 h over a 2-week period; those randomized to the distributed schedule arm completed the 18 h over a 4-week period. In the blocked practice arm, participants practiced one script at a time. They practiced the first script for 9 h (6 treatment days) over 1 week in the massed condition, and over 2 weeks in the distributed condition. Then they practiced