In this column, authors of journal articles related to clinical practice research are invited to discuss current work. ASHA members can access this full-text article, which appears in the October 2008 issue of the Journal of Speech, Language, and Hearing Research. See first reference for full citation.
Constraint-induced language therapy (CILT), a treatment technique for individuals with aphasia, has received considerable attention in the recent literature. Although introduced less than 10 years ago, CILT has garnered much interest among practitioners, researchers, and policy-makers, thereby making the topic one of considerable importance to the profession. Derived from animal studies and modeled after constraint-induced movement therapy used in physical therapy for individuals with limb weakness, CILT encompasses basic neuroscience principles, including forced use of verbal language and massed practice.
In CILT, a small group of patients with aphasia take part in language activities in which they are constrained to verbal responses that are shaped toward more expansive utterances over time. In contrast to other aphasia treatment approaches that promote the use of compensatory communication modalities such as gesture, drawing, or writing, in CILT no compensatory nonverbal communication strategies are allowed during the language activities. Improved verbal responses are the goal of treatment. Furthermore, treatment is provided on an intensive schedule, up to three hours per day for five days per week.
Pulvermuller and his colleagues (2001) reported positive improvements in verbal language abilities using this approach. The problem, however, was in determining whether the positive benefits of CILT emanated from the forced use of verbal language or from the high intensity of treatment. To examine this question, a systematic review of studies examining CILT and aphasia treatment intensity was completed recently in the Journal of Speech, Language, and Hearing Research (Cherney, Patterson, Raymer, Frymark, & Schooling, 2008).
In the first ASHA-sponsored systematic review of CILT, ASHA volunteers Leora Cherney, Janet Patterson, and I worked with National Center for Evidence-Based Practice in Communication Disorders (N-CEP) staff Tobi Frymark and Tracy Schooling and the Advisory Committee on Evidence-Based Practice to pilot a methodology for reviewing treatment studies that could be used for all ASHA systematic reviews. In this review, we address a series of questions (2008) about the effects of CILT specifically and the intensity of aphasia treatment in general for improving language abilities, and maintaining those changes in individuals with acute and chronic aphasia.
Unlike some systematic reviews (e.g., Cochrane Collaboration) in which the scope is limited to prospective randomized controlled trials, ASHA systematic reviews encompass all studies investigating the intended topic, regardless of study design. Ultimately, 10 studies that examined the effects of CILT or that directly compared effects of higher- and lower-intensity aphasia treatment schedules were identified for review. Committee members evaluated those studies for methodologic quality and calculated treatment effect sizes based upon measures of language impairments and communication activity/participation.
Through 2006, five studies of moderate methodologic quality had examined the effects of CILT for individuals largely with chronic nonfluent forms of aphasia. The majority of effect sizes were large when examining CILT outcomes for several language tests as well as measures of communication activity/participation. Two studies indicated that CILT effects were maintained over periods of one to three months.
Six studies varying from low to high in methodologic quality reported a direct comparison of higher- and lower-intensity aphasia treatment, again mostly for individuals with chronic nonfluent forms of aphasia. The majority of effect sizes favored more intensive treatment based upon standardized measures of language processing in aphasia. The findings were mixed when considering outcomes for measures of communication activity/participation such as rating scales and communication samples, as half of the study outcomes favored more intensive treatment and half favored a less intensive, distributed treatment schedule.
Overall, this systematic review found positive effects of CILT and intensive aphasia treatment primarily for individuals with nonfluent chronic aphasia, suggesting that the benefits of CILT may be in part related to the high intensity at which it is delivered. This observation is in keeping with positive effects of intensive treatment reported in other domains, including motor speech (Sapir et al., 2007) and stuttering (Blomgren et al., 2005). Maher and colleagues (2006) noted, however, that forced language use also seems to be a potent factor in CILT. The review also highlights the need for additional research, including the need for treatment studies contrasting forced language use and treatment intensity in individuals with acute aphasia and those with fluent types of aphasia, examining maintenance of treatment effects over longer periods, and incorporating rigorous prospective randomized controlled trials.