Edited by: Donald T. Stuss, Baycrest Centre for Geriatric Care, Canada
Reviewed by: William Milberg, Harvard Medical School, USA; Elizabeth Rochon, University of Toronto, Canada
*Correspondence: Jill S. McClung, Department of Communicative Disorders/Rehabilitation Science, College of Public Health and Health Professions, University of Florida, PO Box 100174, Gainesville, FL 32610-0174, USA. e-mail:
This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
One of the greatest challenges to language rehabilitation is reconciling the fact that the same therapeutic intervention, provided to different individuals with similar types of stroke-induced aphasia, may result in divergent outcomes. In this paper, the authors reviewed existing literature to identify relevant ambient factors – those outside the control of the clinician – that may potentially influence functional language recovery in aphasia and response to treatment. The goal was to develop a clinical history-taking tool to assist clinicians in gathering information germane to each individual's unique circumstances and environment, elements that may have previously been underestimated, to provide a complete inventory of potentially potent prognostic factors. First, two of the authors, speech–language pathologists experienced in aphasia rehabilitation, identified and categorized factors that seemed likely to influence aphasia outcomes. Then, a wide range of literature was reviewed in an effort to identify factors empirically found to be potent influences on aphasia recovery. Where studies relating these factors to aphasia were not found, relevant research from allied fields that examined recovery from brain injury is reported. Moreover, some factors thought to be potentially potent have yet to be examined. Finally, the ambient factors supported by evidence were categorized as facilitators or barriers to functional improvement, and the Ambient Influences on Outcome Checklist (AOC) was developed, including only those factors shown to be potent in the recovery process. It is hoped that this checklist can be used to more broadly assess potential prognostic influences in aphasia restitution, as well as spawn further research.
Stroke is the leading cause of adult long-term disability worldwide (Whitall,
In a paper describing neuroplasticity related to constraint-induced movement therapy (CIMT), Nadeau and Wu (
The current paper focuses on identifying potential ambient factors that may be influential in the language recovery of individuals with stroke-induced aphasia through a review of existing literature. It is hoped that this literature review, as well as the Ambient Influences on Outcome Checklist (AOC) that was developed, while not yet tested psychometrically, will both assist evaluators in assessing the potential for recovery of their patients with aphasia, and highlight the crucial need for additional research in the unstudied areas.
Studies of neurorehabilitation and recovery post-stroke focus on two mechanisms – neurobiological processes and experiential processes. Neurobiological processes include the endogenous chemical and physiological processes associated with recovery of neurons from the acute insult, and subsequent neurogenesis and neural migration, axonal sprouting and migration, and synaptogenesis – processes that can be subsumed under the term “reactive plasticity” (Nadeau and Wu,
Experiential processes, on the other hand, are exogenous processes that induce replacement of knowledge and skills lost due to brain injury. New knowledge and skills are encoded in the brain primarily through synaptogenesis and alteration of existing and new synaptic connection strengths. These processes likely recruit normal neural learning mechanisms and may result from combined contributions of therapeutic and ambient experiences. Facilitory experiential processes in humans are analogous to environmental enrichment in animal studies, defined as one or a combination of: (1) enhanced social interaction, (2) increased physical activity, and/or (3) increased learning opportunities (Dahlqvist et al.,
Experiential processes in neurorehabilitation take two forms – therapeutic experience and ambient experience. As previously described, the therapeutic experience for persons with aphasia encompasses direct cognitive–linguistic interventions orchestrated within the clinical environment by the speech–language pathologist. Aphasia intervention, controlled by the clinician, is primarily implemented via task practice. It may be modified by the clinician based on feedback from the patient and/or caregivers, and may also include skill practice beyond the clinic in natural settings to promote generalization. Successful therapeutic experience has been shown to facilitate neuroplastic changes, as illustrated in imaging studies (Adair et al.,
Until the current review, ambient experience had been neither defined nor fractionated into factors that may be important in aphasia recovery. The authors define ambient experience as the sum total of characteristically uncontrolled influences on the individual with aphasia, related to severity and recovery potential, that exist outside the clinical environment. This construct may be divided into several functionally useful subcategories (Figure
First, intra-individual factors may be identified, including pre-stroke factors (Threats,
First, two licensed speech–language pathologists experienced with aphasia intervention created a list of factors suspected to influence language recovery in aphasia. Once this list was developed, a literature review was conducted via PubMed and Psych Info databases searching a combination of the following keywords: aphasia, severity, environmental enrichment, family, social, leisure, ethnic, education, financial, gender, friend, marital, spouse, work, socioeconomic, environment, caregiver, outcome, employment, religion, spirituality, culture, psychological, coping, and depression. Studies from a diverse range of fields were reviewed, and are specified in Table
Ambient factor | Reference | Discipline | Population | |||
---|---|---|---|---|---|---|
Gender |
Angeleri et al. ( |
Neurology | Stroke | |||
DiCarlo et al. ( |
Neurology | Stroke | ||||
Eriksson et al. ( |
Neurology | Stroke | ||||
Gargano et al. ( |
Epidemiology | Stroke | ||||
Gargano and Reeves ( |
Epidemiology | Stroke | ||||
Glader et al. ( |
Neurology | Stroke | ||||
Glader et al. ( |
Neurology | Stroke | ||||
Holroyd-Leduc et al. ( |
Neurology | Stroke | ||||
Kapral et al. ( |
Epidemiology | Stroke | ||||
Lai et al. ( |
Epidemiology | Stroke | ||||
Paolucci et al. ( |
Epidemiology | Stroke | ||||
Sturm et al. ( |
Epidemiology | Stroke | ||||
Age |
Ahlsio et al. ( |
Neurology | Stroke | |||
Brown and Grober ( |
Neurology | Aphasia | ||||
Code ( |
Rehabilitation | Aphasia | ||||
Jorgensen et al. ( |
Epidemiology | Stroke | ||||
Kleim and Jones ( |
Neurology | Aphasia | ||||
Levin ( |
Neurology | TBI | ||||
Ross and Wertz ( |
Rehabilitation | Aphasia | ||||
Smith ( |
Rehabilitation | Aphasia | ||||
Thompson et al. ( |
Epidemiology | TBI | ||||
Pre-stroke depression |
Provinciali and Coccia ( |
Neurology | Stroke | |||
Williams et al. ( |
Neurology | Stroke | ||||
Ethnic/cultural background |
Arango-Lasprilla and Niemeier ( |
Neurology | TBI | |||
Bravata et al. ( |
Epidemiology | Stroke | ||||
Saltapedas and Ponsford ( |
Neurology | TBI | ||||
Language(s) spoken | Bates et al. (1991) | Neurology | Aphasia | |||
Bates et al. (1991) | Neurology | Aphasia | ||||
Goodglass ( |
Rehabilitation | Aphasia | ||||
Lambon Ralph and Ehsan ( |
Neurology | Aphasia | ||||
Wulfeck et al. ( |
Neurology | Aphasia | ||||
Educational level | Bennett et al. ( |
Neurology | Alzheimer's | |||
Connor et al. ( |
Neurology | Aphasia | ||||
de Riesthal and Wertz ( |
Rehabilitation | Aphasia | ||||
Lazar et al. ( |
Rehabilitation | Aphasia | ||||
Ross and Wertz ( |
Rehabilitation | Aphasia | ||||
Smith ( |
Rehabilitation | Aphasia | ||||
van den Bos et al. ( |
Epidemiology | Stroke | ||||
Socioeconomic status |
Braveman et al. ( |
Epidemiology | Public Health | |||
Connor et al. ( |
Neurology | Aphasia | ||||
Cox et al. ( |
Neurology | Stroke | ||||
Jakovljevic et al. ( |
Epidemiology | Stroke | ||||
van den Bos et al. ( |
Epidemiology | Stroke | ||||
Weir et al. ( |
Epidemiology | Stroke | ||||
Handedness | Basso et al. ( |
Neurology | Aphasia | |||
Code ( |
Rehabilitation | Aphasia | ||||
Holland et al. ( |
Rehabilitation | Aphasia | ||||
Pedersen et al. ( |
Epidemiology | Aphasia | ||||
Smith ( |
Rehabilitation | Aphasia | ||||
Pre-ictal brain organization | Bates et al. (1991) | Neurology | Aphasia | |||
Brown et al. ( |
Neurology | Aphasia | ||||
Nadeau and Gonzalez-Rothi ( |
Neurology | Aphasia | ||||
Genetic and epigenetic influences | Abrahams et al. ( |
Neurogenetics | Tissue | |||
Kleim et al. ( |
Neurogenetics | Polymorphism | ||||
Strauss et al. ( |
Neurogenetics | Epilepsy | ||||
Vernes et al. ( |
Genetics | Specific Lang. Impairment | ||||
Extent of lesion |
Lazar et al. ( |
Rehabilitation | Aphasia | |||
Lendrem and Lincoln ( |
Rehabilitation | Aphasia | ||||
Pedersen et al. ( |
Epidemiology | Aphasia | ||||
Rijntjes ( |
Rehabilitation | Aphasia | ||||
Stineman and Granger ( |
Nursing | Stroke | ||||
Depression |
Ahlsio et al. ( |
Neurology | Stroke | |||
Code ( |
Rehabilitation | Aphasia | ||||
Eslinger et al. ( |
Psychology | Stroke | ||||
Gonzalez-Torrecillas et al. ( |
Psychiatry | Stroke | ||||
Kimura et al. ( |
Psychiatry | Stroke | ||||
King ( |
Psychology | Stroke | ||||
Kwok et al. (2007) | Rehabilitation | Stroke | ||||
Lo et al. ( |
Rehabilitation | Stroke | ||||
Meijer et al. ( |
Rehabilitation | Stroke | ||||
Provinciali et al. ( |
Neurology | Stroke | ||||
Ramasubbu and Patten ( |
Psychiatry | Stroke | ||||
Robinson et al. ( |
Psychiatry | Stroke | ||||
Williams et al. ( |
Nursing | Stroke | ||||
Expectations | Bluvol and Ford-Gilboe ( |
Nursing | Stroke | |||
Duncan et al. ( |
Rehabilitation | Stroke | ||||
Jeffreys ( |
Education | Students | ||||
Johansson ( |
Neurology | Animal studies | ||||
McKevitt et al. ( |
Neurology | Stroke | ||||
Redfern et al. ( |
Neurology | Stroke | ||||
Time post onset | Cramer ( |
Neurology | Stroke | |||
Hochstenbach et al. ( |
Rehabilitation | Stroke | ||||
Hochstenbach et al. ( |
Rehabilitation | Stroke | ||||
Meinzer et al. ( |
Psychology | Aphasia | ||||
Mimura et al. ( |
Rehabilitation | Aphasia | ||||
Moss and Nicholas ( |
Neurology | Aphasia | ||||
Raymer et al. ( |
Neurology | Aphasia | ||||
Rijntjes ( |
Neurology | Aphasia | ||||
Robey ( |
Rehabilitation | Aphasia | ||||
Sarno and Levita ( |
Rehabilitation | Aphasia | ||||
Exercise |
Arkin ( |
Rehabilitation | Alzheimer's | |||
Research | Elders | |||||
Colcombe and Kramer ( |
Psychology | Elders | ||||
Colcombe et al. ( |
Psychology | Elders | ||||
Marks et al. ( |
Aging | Elders | ||||
Netz et al. ( |
Physiotherapy | Middle aged | ||||
Winter et al. ( |
Neurology | Healthy adults | ||||
Spirituality | Ellison ( |
Psychology | Healthy adults | |||
Frame et al. ( |
Counseling | HIV/AIDS | ||||
Idler ( |
Psychology | Elders | ||||
Physical living Environment | Brush ( |
Rehabilitation | Alzheimer's | |||
Harrison et al. ( |
Neurology | Stroke | ||||
Lorenz ( |
Nursing | Hospital | ||||
Wehr et al. ( |
Neurology | Affective | ||||
Wood et al. ( |
Nursing | Alzheimer's | ||||
Zeisel et al. ( |
Nursing | Alzheimer's | ||||
Occupational status | Melin et al. ( |
Rehabilitation | Public | |||
Neau et al. ( |
Neurology | Young stroke | ||||
Leisure Status |
Hartman-Maeir et al. ( |
Rehabilitation | Stroke | |||
Sveen et al. ( |
Aging | Stroke | ||||
Communication partners – spouses |
Blonder ( |
Rehabilitation | Aphasia | |||
Brosseau et al. ( |
Rehabilitation | Stroke | ||||
Burns et al. ( |
Neurology | Aphasia | ||||
Glosser and Deser ( |
Neurology | Aphasia | ||||
Manzo et al. ( |
Neurology | Aphasia | ||||
Meijer et al. ( |
Rehabilitation | Stroke | ||||
Milroy and Perkins ( |
Rehabilitation | Aphasia | ||||
Niemi et al. ( |
Neurology | Stroke | ||||
Jorgensen et al. ( |
Epidemiology | Stroke | ||||
Pedersen et al. ( |
Epidemiology | Aphasia | ||||
Perkins ( |
Rehabilitation | Aphasia | ||||
Communication partners – family |
Duncan et al. ( |
Rehabilitation | Stroke | |||
Eslinger et al. ( |
Psychology | Stroke | ||||
Glass et al. ( |
Epidemiology | Stroke | ||||
King ( |
Neurology | Stroke | ||||
Meijer et al. ( |
Rehabilitation | Stroke | ||||
Ouimet et al. ( |
Psychology | Stroke | ||||
Tsouna-Hadjis et al. ( |
Rehabilitation | Stroke | ||||
Communication partners – psychosocial | Arai et al. ( |
Nursing | Disabled elders | |||
attributes |
Bates et al. ( |
Rehabilitation | Stroke | |||
Barskova and Wilz ( |
Psychology | Stroke | ||||
Cameron et al. ( |
Rehabilitation | Stroke | ||||
Croteau and LeDorze ( |
Rehabilitation | Aphasia | ||||
Evans et al. ( |
Counseling | Stroke | ||||
Greenberger and Litwin ( |
Nursing | Disabled elders | ||||
Low et al. ( |
Psychology | Stroke | ||||
Perrin et al. ( |
Psychology | Stroke/Aphasia | ||||
Zraick and Boone ( |
Rehabilitation | Aphasia | ||||
Communication partners – friends |
Cruice et al. ( |
Rehabilitation | Aphasia | |||
Cruice et al. ( |
Rehabilitation | Aphasia | ||||
Davidson et al. ( |
Rehabilitation | Aphasia | ||||
Elman ( |
Aphasiology | Aphasia | ||||
Hilari and Northcott ( |
Aphasiology | Aphasia | ||||
Hopper et al. ( |
Aphasiology | Aphasia | ||||
Ross et al. ( |
Rehabilitation | Aphasia | ||||
Sacchett et al. ( |
Rehabilitation | Aphasia | ||||
Sarno ( |
Aphasiology | Aphasia | ||||
Communication partners – society |
Brown et al. ( |
Rehabilitation | Aphasia | |||
Garcia et al. ( |
Rehabilitation | Aphasia | ||||
Howe et al. ( |
Rehabilitation | Aphasia | ||||
Howe et al. ( |
Rehabilitation | Aphasia | ||||
Kagan et al. ( |
Rehabilitation | Aphasia | ||||
Parr, et al. ( |
Rehabilitation | Aphasia | ||||
Parr and Byng ( |
Rehabilitation | Aphasia | ||||
Ross et al. ( |
Rehabilitation | Aphasia | ||||
Rayner and Marshall ( |
Rehabilitation | Aphasia | ||||
Simmons-Mackie et al. ( |
Rehabilitation | Aphasia | ||||
Health care professionals | Boylstein et al. ( |
Rehabilitation | Stroke | |||
Worrall ( |
Rehabilitation | Aphasia |
Evidence-based factors were organized within a framework that parallels the internationally accepted framework defined by the World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF, World Health Organization [WHO],
Presented here is the evidence found to be related to each factor within the framework established for ambient environmental components. The authors attempt to fractionate and clarify these elements in the context of the framework, and conclude by integrating them into a working history-taking tool (Figure
There has been an implicit assumption in the aphasia treatment literature that the most important determinant of language impairment is the extent of damage caused by the stroke (Kertesz et al.,
A substantial number of registry-based studies worldwide have demonstrated that women experience greater stroke severity and poorer functional outcomes than men. Large studies in the United States, Europe, Canada, and Scandinavian countries have reported that women may receive fewer medical diagnostic procedures (Gargano et al.,
Likewise, Gargano et al. (
Both animal and human studies of age-related neuroplasticity have found that even though the aged brain exhibits slower neural processes, it is a combination of genetics and individual lifetime experiences that determines the quantity and quality of reorganization possible (Kleim and Jones,
One such study investigated associations between severity of language disorder in chronic aphasia and age (Smith,
A large Scandinavian study, The Copenhagen Stroke Study, examined a more global range of stroke recovery factors, and determined that one of the best predictors of positive functional outcome, including speech and language function, was younger age (Jorgensen et al.,
In other stroke studies, age has been found to be significantly related to ADL recovery. Ahlsio et al. (
In studies of traumatic brain injury, older age has also been determined to lead to less favorable outcomes (Thompson et al.,
Evidence has implicated pre-stroke depression as a significant predictor of reduced stroke and aphasia recovery (Williams et al.,
Although the study of cultural issues in rehabilitation is relatively new, recent research has examined such factors in the setting of traumatic brain injury. Minority populations in the United States, including Native American Indians, Hispanics, and African Americans, have been demonstrated to be at higher risk for brain injury, as well as for greater severity of consequences, than are Caucasians (Bravata et al.,
The strongest determinant of language function post-stroke is the pre-ictal language spoken (Bates et al.,
Dramatic inter-language differences have been noted in other domains of language function. For example, in English, newly introduced concepts are commonly given substantially or completely novel names, whereas in Chinese, there has always been a strong propensity for creating names for new concepts by combining old words (e.g., “look-book” for “read”) (Bates et al.,
Evidence from allied health fields has suggested that higher levels of formal educational achievement may buffer the central nervous system from neurological insult (Bennett et al.,
In an early study of 78 individuals with chronic aphasia, Smith reported a significant correlation between higher levels of education, i.e., over 12 years of schooling, and greater residual language function (Smith,
The predictive value of educational background in determining outcomes has been demonstrated in studies of long-term functional disability after stroke (van den Bos et al.,
Although SES has been discussed in a large number of health-related studies, its multidimensional nature has made its status as a predictor of functional recovery from stroke somewhat uncertain. For example, the U.S. generally uses either the number of years of formal schooling or annual taxable income to define SES, whereas Europe typically defines it as occupational class (Jakovljevic et al.,
Epidemiological studies have identified correlations between SES, general health, and access to health care (Mortimer and Graves, 1993 in Connor et al.,
Evidence has been mixed about the prognostic value of handedness in aphasia severity and recovery (Code,
However, in studies that have specifically examined the influence of strong left-hand preference, no relationships have been found between handedness and functional hemispheric organization (Hecaen and Sauguet, 1971, in Basso et al.,
Every clinician has observed variability in the degree to which different patients with seemingly identical lesions recover language function. At times this may be quite dramatic: right-handed patients with very large left hemisphere strokes recover normal or nearly normal language function, in some cases only to experience recurrent aphasia with a right brain lesion (Nadeau and Gonzalez-Rothi,
Heterozygous mutations of the FOXP2 gene have been identified as a cause of specific language impairment (SLI), a rare Mendelian inherited speech and language disorder (Vernes et al.,
Recovery of language function after stroke is also almost certainly affected by genetic factors influencing neuroplasticity. For example, neuroplasticity appears to be reduced in subjects with the val66met polymorphism in brain derived neurotrophic factor, compared with subjects with the val66val and met66met polymorphisms (Kleim et al.,
Epigenetic factors may exert as yet undetermined influences. Epigenetics involves modulation of gene expression. The pattern of gene expression not only evolves through the lifetime, but it may, to some degree, be inherited, thereby instantiating a neo-Lamarckian version of evolution. The potential power of epigenetic influences should not be underestimated. They are, for example, responsible for the metamorphosis of caterpillar into pupa and ultimately, butterfly.
Although genetic and epigenetic factors are likely to have a profound influence on the development of and recovery from aphasia after stroke, and although almost certainly we will 1 day discover ways of manipulating them, because so little is understood about them at this time, they have not been included in the AOC.
With very few exceptions, researchers have demonstrated that lesion site and size are critical factors in determining recovery from aphasia (Lendrem and Lincoln,
Researchers have demonstrated that psychosocial adjustment and emotional state post-stroke constitute critically important influences in recovery (Code and Muller, 1992 in Code,
There is a higher likelihood of depression after stroke when the person experiences aphasia (Damecour and Caplan, 1991, in Provinciali and Coccia,
Successful treatment of depression in stroke survivors improves both mood and functional outcomes (Eslinger et al.,
The potential impact of patient and caregiver expectations on stroke recovery has been discussed by a number of researchers (Jeffreys,
Whether or not language therapy is provided for aphasia is not a proposed factor in this review. However, the time following stroke onset at which treatment is initiated is considered an ambient factor. Neural reorganization following acute stroke occurs in a sequential pattern, based on clinical and translational studies (Rijntjes,
Therefore, controversy still exists as to the ideal time after stroke and the intensity of therapeutic intervention that will produce optimal functional recovery. It may be that time post onset becomes less influential past a certain period in the recovery process, as suggested in a study of individuals with aphasia by Moss and Nicholas (
In a meta-analysis of 21 studies examining treatment effects in aphasia rehabilitation, Robey reported that when speech–language therapy was implemented within the first 4 months following stroke, therapeutic gains were nearly twice as large as when treatment occurred after 4 months (Robey,
Although no studies were found relating exercise specifically to aphasia outcomes, many have examined its effects on brain function in healthy young and older adults, persons with respiratory disorders, individuals with Alzheimer's disease, and persons with depression. A number of papers have investigated neurophysiological changes that have resulted from augmented aerobic, but not non-aerobic, physical fitness. For example, in older adults, aerobic interventions have resulted in increased white matter integrity (Marks et al.,
A number of prospective cohort studies have shown an association between greater physical activity at baseline and attenuated rate of cognitive decline or reduced incidence of dementia in subsequent years (Lautenschlager et al.,
Despite an implicit acknowledgement in the literature of the importance of spirituality on health outcomes, few empirical studies were identified. The authors found no studies examining the effects of spirituality on aphasia recovery, and only a limited number investigating it in other health contexts that reported data collection and analysis. A large study of men with HIV/AIDS examined spirituality self-ratings in relation to the efficacy of counseling interventions (Frame et al.,
On the other hand, several sociological studies of healthy older adults have demonstrated positive links between faith-based activities and quality of life. Idler (
Some healthcare literature has examined the effects of physical environment on several patient populations, particularly individuals with dementia, though none has addressed persons with aphasia. Certain environmental features, including architectural design, are strongly associated with vital health and behavioral outcomes in individuals with Alzheimer's disease (Zeisel et al.,
Studies of environmental factors related to the recovery of ill individuals in hospitals and other institutional settings have been reported in the nursing literature. Lorenz (
One study that targeted physical environmental influences on the abilities of stroke patients was located (Harrison et al.,
Although a number of studies examined vocational outcomes following stroke, none reported on aphasia recovery. Neau et al. (
A number of studies have examined the relationship between life satisfaction and level of participation in daily activities following stroke. Most have demonstrated that involvement in leisure activities, an element of instrumental ADL (IADL), contributes significantly to reports of well-being. For instance, Hartman-Maeir et al. (
Similar conclusions were reported in a Norwegian study that examined the relationship between subjective well-being and IADL independence (Sveen et al.,
Marital status has been shown to be predictive of the location to which individuals are discharged 6–12 months following stroke (Meijer et al.,
That one has a spouse has recently been shown to be instrumental in enriching or diminishing the recovery process in persons with aphasia. In studying communication interchanges between stroke survivors and spouses, Blonder (Blonder,
Three predictors of quality of life in individuals between 1 and 3 years post-stroke – social support, depression and functional ability – have been noted by King (
Several aphasia-specific studies have investigated spousal perceptions of their partners with aphasia. Croteau and LeDorze (
The interdependence of stroke patients’ recovery and their caregivers’ attitudes has also been studied recently, highlighting the importance of caregivers’ psychological status to the patient's recovery. One study used structural equation modeling to examine the relationships between caregivers’ psychosocial functions and their care recipients’ abilities, including language function (Perrin et al.,
Finally, Low et al. (
A number of studies have examined the importance of social interaction in the recovery of language function and psychosocial well-being in individuals with aphasia (Hopper et al.,
Satisfaction with social support received from friends has been identified as a significant predictor of quality of life by individuals with chronic aphasia (Ross and Wertz,
Societal effects on the functioning of persons with aphasia have been extensively studied since the adoption of the ICF model by the American Speech-Language Hearing Association (ASHA) in 2001. The ability to access information, health care services, and transportation has been found to strongly impact the quality of life reported by individuals with chronic aphasia (Ross and Wertz,
A review of influential environmental factors conducted by the same group (Howe et al.,
Although health care professionals provide interventions that by definition are within the context of therapeutic experience, the interpersonal relationships that they have with patients also play an important ambient experience role in facilitating recovery in patients with stroke and aphasia. Boylstein et al. (
The authors have incorporated the empirically supported factors just discussed (Table
The ultimate goal for patients with aphasia is to attain maximal functional recovery based on the contextual synthesis of both therapeutic and ambient experiences. In order to achieve this goal, every therapeutic gain must be generalized to the everyday living environment. There has been essentially no systematic research on mechanisms of generalization, but a number have been postulated (Nadeau et al.,
Extrinsic generalization involves the development during therapy of a knowledge acquisition or skill learning technique that subjects with motivation, and capable of engaging motivation to employ the technique, can use during and outside therapy to rebuild language function. Several ambient factors listed on the AOC, including Pre-stroke and Post-stroke Depression, Leisure Status, and Communication Partners and their Psychosocial Attributes, are likely to influence the extent to which generalization of skills beyond the clinical setting occurs. Thus, elements such as an individual's outlook, volitional involvement in activities, and support by family, friends, and society, could be essential in instantiating and sustaining extrinsic generalization as a part of the ambient experience.
Mechanistic generalization involves the training of a key brain resource, essential to language processing but not fundamentally linguistic, that enables improvement in language function. One such mechanism is intentional predisposition to use language, either in lieu of other communication techniques such as gesture, or in lieu of giving up on all attempts to communicate beyond the most basic of needs. Constraint-induced language therapy (CILT) attempts to develop intentional predisposition to use language by engaging subjects with aphasia in situations in which they must communicate and the only way to communicate effectively is verbally (Pulvermuller et al.,
Contextual generalization involves the acquisition of knowledge, predominantly contextual, during language therapy for aphasia, that aids retrieval of knowledge outside of therapy. In essence, the principle is that when individuals learn, the knowledge that is acquired includes not only the intended material but also knowledge about the context. This contextual knowledge may include attributes of other stimuli introduced during a treatment session. It may also include more general attributes of the situation, e.g., where the treatment was provided, characteristics of the treatment room and the therapist, who else was present, the mood of the participant, participant attitudes to the stroke experience and associated disability, and the strategies the participant brings to therapy. The greater the resemblance between context in the learning environment and context in the retrieval environment, the higher is the likelihood of success in knowledge retrieval. The nature of the ambient experience has a profound influence on the extent of commonality between it and the therapeutic experience. To maximize contextual generalization requires modifying therapeutic and ambient experiences to maximize commonality. Explicitly incorporating components of the retrieval environment, likely influenced by Socioeconomic Status, Ethnic/Cultural Background, and Leisure Status, into the treatment environment has the potential for fusing ambient and therapeutic experience with attendant benefits for communicative effectiveness.
Finally, Socially Mediated generalization involves changes in the perceptions of the subject and the subject's family regarding his/her role in the family unit, the adoption of a new or revised role that subsumes more expectation of speech, more pressure to speak, and greater language production (Blonder,
In summary, the authors have identified a considerable number of ambient experience factors relevant to aphasia recovery, but few have been adequately studied. The review is extensive, but not exhaustive. Literature outside the realm of aphasia-specific research has been examined to provide evidence in other related populations, but each factor may be potentially crucial for the neural and behavioral recovery of individuals with aphasia as well.
The authors wish to emphasize that the AOC clinical inventory tool is intended to serve as a guide for gathering relevant information to be considered by the clinician during the history-taking process. No attempt has been made to test its validity or reliability. It reflects the authors’ interpretation of the current state of literature, and is meant to provide therapists with a greater cognizance of potent variables that may impact their patients’ recovery beyond the clinic. In this regard, it is a work in progress, for it is hoped that future research will include testing it in the field and gathering empirical data to assess its validity and reliability. Until follow-up studies are implemented to address psychometric testing, clinicians are encouraged to use their best clinical judgment when implementing the AOC to assess the relative importance of each factor for each individual patient.
It is evident that numerous factors influence rehabilitation in individuals with aphasia. Functional independence and well-being are predicted by a combination of stroke severity, mental health, demographics, and economic variables (Ostwald et al.,
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
The authors wish to thank Dr. Jay Rosenbek, Professor and Mentor, University of Florida College of Public Health and Health Professions, Rehabilitation Science and Communicative Disorders Departments, for his insight, inspiration, and support, as well as the Brain Rehabilitation Research Center, Malcom Randall DVA Medical Center, and McKnight Brain Institute for their resources. They also would like to acknowledge Dr. Leslie Gonzalez Rothi as the current recipient of the DVA Research Career Scientist Award and the University of Florida Bob Paul Family Endowed Chair in Neurology.