namely, duration, intensity, and frequency. There exist models of communication that describe and explain the rules that people intuitively use when they interact with one another.
Theories, models, and frameworks constitute the underlying bases on which science is organized and upon which science will progress. They are used to organize, describe, and investigate elements of knowledge and the constituents of a concept of interest. For example, Gagné, Southall, and Jennings (2009) described a theoretical model (Major & O’Brien, 2005) that can be used to describe and explain how the phenomenon of stigma may operate in people who have a hearing loss. Conceptual models provide precise and comprehensive definitions of concepts. Hyde and Riko (1994, p. 347) argued that “terminology is more than labels; it reflects and affects its underlying constructs and it provides a vehicle for debate and research.” Moreover, conceptual models provide the basis on which various people from different backgrounds can have common understanding and perspective. Conceptual models provide the foundation on which a phenomenon is conceived, described, analyzed, understood, and explained. They constitute the starting point from which research questions are identified and hypotheses are tested. In rehabilitative audiology (as in all other health disciplines), conceptual models guide the way clinical services are organized, designed, and dispensed. Furthermore, these frameworks influence the type of research that takes place within a discipline, as well as how that research is organized and conducted.
From a clinical perspective, the conceptual framework adopted will determine how AR is conceived and perceived. This framework will influence how we define AR, and will govern rehabilitation services selected and provided. Moreover, it will influence how we evaluate the effects and benefits of the services provided.
From a research perspective, the conceptual framework chosen will determine the research issues to be addressed. In turn, the research question addressed or the hypothesis tested will influence the experimental paradigm used and the type of data collected and analyses to be performed to test the hypotheses formulated. Moreover, it will influence the conclusions that are drawn from research investigations.
Imagine two audiologists who adhere to different conceptual frameworks of AR. The conceptual framework adopted by one audiologist may lead them to design a program that aims to eliminate a client’s hearing loss. Based on a different conceptual framework, the other professional’s goal may be to reduce or eliminate the deleterious effects of hearing loss on the client’s everyday life activities. Under such circumstances, it is likely that, for the same client, the treatment program selected by one audiologist will be different from the program selected by the other professional. Furthermore, it is very likely that the research methodology used, as well as the method and criteria employed to evaluate the success of their intervention program, will differ across the two professionals. As unlikely as it may seem, in AR, as in other rehabilitation sciences, dramatically different conceptual frameworks have been used to guide the types of rehabilitation services provided to people with hearing loss and to quantitatively and qualitatively describe the outcomes of those services. Needless to say, for a discipline to progress and improve, the conceptual frameworks underlying that discipline must be appropriate, realistic, and valid. Over the years, the types of conceptual frameworks used to characterize AR have evolved.
A Medical Model of Health
Given its long history, its importance, and the overwhelming presence of medicine in Western societies, the medical model has been the predominant conceptual framework of health used in all health-related disciplines. The medical model is grounded in causal logic. Health care professionals aim to identify and explain a patient’s symptoms based on what causes them. Stated simplistically, in a medical model of health, patients have symptoms that are caused by diseases or impairments. Based on the symptoms, a remedy or treatment is selected and applied (e.g., the prescription of medication, surgery, a program of exercises, dietary regime, etc.). A treatment is considered successful if, after its administration, the symptoms, the disease, or the impairment disappears. As a result of the treatment, the patient is cured and the person reestablishes the condition of health held before consulting the health care professional (Duchan, 2004). This conceptualization of health is very “body oriented.” This model is effective when the treatment program is at the level of the cell, organ, or body structure. For example, health problems often require the elimination of a virus (e.g., an organism that causes a cold, the flu, or a childhood disease), the removal of a body part (e.g., tonsils, gallstones, tumors), or the repair of a body structure (e.g., fractured leg or arm) to restore “normal” function. In a medical model of health, the goal of a treatment program is to “cure” the patient (i.e., to restore normal biological functioning or to minimize the impact of the patient’s symptoms; Duchan, 2004). This conception of health promotes a view of pathology as an entity in isolation from the affected individual. Such a view of health has limited relevance for chronic, progressive, and irreversible diseases such as sensorineural hearing loss (Hyde & Riko, 1994).
The health issues addressed by professionals who provide rehabilitation services are very different from the acute health care issues that can be conceptualized within a medical model. In the domain of rehabilitation, the health problems of the people seeking help are usually chronic. Often, the health problem is irreversible and cannot be resolved in a short period of time. Consequently, people with chronic health problems have to learn to cope with the effects of their health condition and modify their lifestyle. Often, the chronic nature of the health condition will have deleterious effects on non-body-related dimensions of the individual’s personal life (e.g., at the psychological, social, economic, and levels, as well as the level of leisure activities) and the social integration of that person in society.
It may not be appropriate to use a medical model to conceptualize the health and treatment needs of people who have chronic disorders such as a permanent sensorineural hearing loss. At the present time, beyond the services that might initially be provided to the person with a permanent hearing loss (e.g., injection of cortisone), there is not much that can be done medically to restore the person’s hearing abilities. Although a number of helpful rehabilitation services may be provided, none of those treatments are likely to cure the hearing loss. Thus, viewed from the perspective of the medical model of health, it is difficult to imagine treatment programs that would be shown to be effective. That is, at the present time, the availability of treatment programs designed to eliminate sensorineural hearing loss are limited (although some progress is being made with respect to treatments that regenerate hair cells at the level of the cochlea). The person has a hearing loss before the rehabilitation services are provided and will continue to have a hearing loss after having completed the rehabilitation program. Hence, if the criterion used to evaluate the benefits provided by a rehabilitation program consists of evaluating aspects of hearing impairment, it is unlikely that the program will be shown to be successful (Gagné, 1998, 2000; Gagné, McDuff, & Getty, 1999).
Although it is never explicitly stated, it can be argued that, in the past, rehabilitation services and evaluation research in AR were designed and evaluated exclusively according to a medical model of health. For example, several decades ago, the unstated goal of fitting hearing aids was to restore normal hearing acuity. The appropriateness of a hearing aid fitting was evaluated according to the results of the aided audiogram or measures of functional aided hearing. An intervention program (i.e., fitting hearing aids) was deemed to be successful if the aided auditory detection thresholds were within the audiometric limits of normal hearing (Olsen, Hawkins, & Van Tasell, 1987; Skinner, 1988). The unstated premise here was that the hearing aids would cure the hearing loss. Similarly, the efficacy of a speechreading training program was evaluated by comparing the speechreading proficiency of a participant before and after the speechreading program was administered (Binnie, 1977). The underlying assumption was that the speech perception problems associated with hearing loss would be cured if the participant displayed improvements in speechreading proficiency (or audiovisual speech-perception proficiency) based on post-treatment speech perception tests administered in a laboratory setting. The results of these investigations provided little information on how different (hopefully better) the person’s speech perception proficiency or conversational fluency was while accomplishing his or her everyday living activities.
Based on the conceptual models of health that were available and used at the time, it is not surprising that the results of evaluative research investigations generally were not successful in demonstrating the benefits of AR. The underlying premise of the medical model, and the type of outcome measures typically used to evaluate benefit (both clinically and in research projects), were not suitable to the goals of rehabilitation. It was not until the 1980s that other conceptual models of health were developed and applied to rehabilitation sciences.
The International Classification of Impairment, Disability, and Handicap
According to the WHO (1948), health is a “state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” This view extends the conception of health beyond the level of body parts and body functions. In 1980, the WHO proposed an international classification of health that attempted to describe encapsulate its conception of health and well-being. A main objective of the ICIDH (WHO, 1980) was to propose a generic model of health and rehabilitation that would be applicable to and internationally accepted by all forms of rehabilitation services, regardless of the discipline. The ICIDH (WHO, 1980) considers the effects that diseases and disorders may have at the organic level (impairments), at the level of the individual in real-life settings (disabilities), and at the sociocultural level (handicaps). The WHO (1980) definitions of impairment, disability, and handicap are provided in Table 3–1. A visual representation of the ICIDH (WHO, 1980) conceptual framework is shown in Figure 3–1.
According to this framework, hearing impairments are dysfunctions in body structures or body functions that are measurable in the laboratory or clinic. For example, an individual’s audiogram may reveal the presence of elevated bone conduction detection thresholds. Or, the result of laboratory experiments may demonstrate that an individual has broader than normal auditory psychophysical tuning curves. The results of both tests are indicative of a hearing impairment attributable to some pathology in the hearing system. A disability is defined as a restriction or inability, resulting from an impairment, to perform an activity in the manner or within the range considered normal for a human being. Examples of hearing disabilities include having poor auditory localization skills and poor speech-perception performances in quiet or in noise. People with hearing impairment who perform less well than matched peers with normal hearing on tasks of auditory sound localization or on speech perception tests would be deemed to display specific hearing disabilities. A handicap is a disadvantage caused by an impairment or a disability that prevents or limits a person from fulfilling the role that would otherwise be considered normal for that individual, given the sociocultural environment in which the person lives. From an audiologic perspective, handicaps are nonauditory problems that result from hearing impairment or disability. For example, a specific job may require that workers be in regular verbal communication with each other, even though the level of noise in the work setting is very high. A person with a hearing loss may experience problems in that work setting if that individual has more difficulties than the other workers understanding speech in noise (i.e., a speech perception in noise disability). In this example, the person with hearing loss would be deemed to have an occupational handicap.
Table 3–1. Definition of Impairment, Disability, and Handicap According to the International Classification of Impairments, Disorders, and Handicaps (ICIDH: WHO, 1980)
Figure 3–1. The relationship between the different components of ICIDH (WHO, 1980).
The following example illustrates how the domains of impairment, disability, and handicap apply to AR. Meningitis, a disease, may damage the inner and outer hair cells at the level of the cochlea, causing an auditory impairment (a severe bilateral sensorineural hearing loss). The impairment may cause the person to experience some hearing disabilities, including poorer performance on speech-perception tasks than peers who have normal hearing. The hearing impairment and associated disabilities may cause handicaps that limit or prevent that person from fulfilling social roles that would be considered normal for that individual. For example, that person may have work-related handicaps due to: the inability to converse on the telephone; difficulties communicating with one other individual in a noisy work environment; or difficulty in taking part in meetings in which several persons are involved. The same person may have leisure-related handicaps due to: the inability to communicate by telephone with friends; difficulty communicating with others in noisy environments such as restaurants; the inability to watch the evening news on the television (because it is not possible to understand the audio signal unless the volume is set very loud or unless the audio signal is amplified); or an inability to take part in bird-watching activities (because the person cannot hear the bird songs or localize where they are coming from).
It is important to recognize that there is not a direct relationship between the domains of impairment, disability, and handicap. An impairment may not always result in a disability, and a disability does not necessarily result in a handicap (Hyde & Riko, 1994). Furthermore, two persons may have the same type and degree of hearing loss but experience differing types or degrees of handicap. Consider the hypothetical case of Tom and Jerry, who have a similar hearing loss. Their hearing loss may make it difficult to take part in conversations that involve two or more participants. This disability (e.g., difficulty conversing in noise) may constitute a work-related handicap for Tom because his job requires that he meet regularly with coworkers to establish their weekly sales objectives. Jerry, one the other hand, may be a mail carrier, a job that does not require him to participate in group meetings. Thus, having difficulty conversing in noise may not be an occupational handicap for Jerry. Further, two persons with different hearing loss may have the same handicap. For example, although Charlie’s hearing loss may be less severe than Tom’s and Jerry’s, he may have the same hearing disability (difficulty conversing in noise). Moreover, that hearing disability may constitute an occupational handicap because Charlie is a waiter in a poorly lit and noisy sports bar where he must interact with his customers.
It is important to note that, according to this conceptual framework, people with hearing loss do not have a hearing handicap; however, they may have a handicap due to their hearing loss. Similarly, a person with a hearing loss is not hearing handicapped; however, in some situations, the person may experience a handicap because of the hearing loss (Stephens & Hétu, 1991). Although it not stated explicitly, according to the ICIDH (WHO, 1980) framework, a handicap is the result of an interaction between, on the one hand, impairments and disabilities and, on the other hand, the particular sociocultural and physical environment in which an activity or an event takes place (Stephens & Hétu, 1991). For example, Natasha, a school crossing guard with a mild to moderate hearing loss may have difficulty localizing sound in space. This disability constitutes a work-related handicap when she directs traffic at a busy street intersection. However, the same disability may not constitute a handicap when she converses with children while standing on the sidewalk. A useful reference, Stephens and Hétu (1991) described how the concepts of impairment, disability, and handicap apply to rehabilitative audiology.
At the time that it was proposed, the ICIDH (WHO, 1980) constituted a major breakthrough for all disciplines of rehabilitation. By extending the concept of health beyond the domains of disorders and impairments, the ICIDH framework provided rehabilitation sciences with an opportunity to develop a different conceptualization of itself and to redefine its goals. Consistent with the ICIDH model (WHO, 1980), the goal of AR can be defined as the alleviation or reduction of hearing disabilities and handicaps encountered by individuals with hearing loss (Gagné & Jennings, 2008). Within this perspective, AR services could be helpful for people with a chronic hearing loss. Whereas, AR cannot cure permanent hearing impairment, some programs can be designed to reduce or eliminate hearing disabilities and handicaps. For example, within a medical (curative) model of health, the stated or implicit goal of providing a client with hearing aids is to restore the client’s impaired hearing abilities (e.g., restoring auditory detection thresholds to normal levels). However, within the perspective of the ICIDH (WHO, 1980), the goal of providing the client with hearing aids may be to eliminate or reduce hearing disabilities (e.g., improving the detection of acoustic alerting signals, improving speech understanding in quiet and/or in noise, making it possible to localize voices or warning signals in space) or to reduce situations of handicap attributable to the hearing loss (e.g., maintaining one’s occupation even though it requires conversing on the telephone; continued appreciation of one’s leisurely activities such as playing Scrabble with friends or watching sports programs on television). By defining the goals of rehabilitation intervention according to disabilities and handicaps, the ICIDH makes it possible to evaluate the efficacy and the effectiveness of specific types of services or programs provided to people with specific impairments and specific needs, defined in terms of disabilities and handicap. For example, how successful is the treatment (e.g., a visual alerting device) in making the client aware that someone is ringing the doorbell? Or, how helpful is the treatment (e.g., earphones connected to a personal infrared amplification system) in enabling the client to understand the television? Conceiving AR from an ICIDH (WHO, 1980) perspective makes it possible to assess the impacts of rehabilitation programs. Also, it provides insights into identifying the types of programs that are most efficacious to manage specific disabilities and handicaps. For example, using a single hearing aid may constitute an efficacious treatment program if the goal of the intervention program is to improve speech comprehension in quiet. The same treatment program may not be as efficacious if the goal of the program is to improve sound localization in a noisy work environment. More importantly, the ICIDH (WHO, 1980) made it possible to demonstrate that, by reducing disabilities and handicaps, the quality of life of people with hearing loss could be improved without altering the person’s disorder or impairment (Mulrow, Aguilar, Endicott, Velez, & Tuley, 1990; Mulrow, Tuley, & Aguilar, 1992).
Notwithstanding its contribution to rehabilitation sciences, there remained some confusion among researchers and professionals concerning the concepts addressed in the ICIDH model. For example, some people had difficulty establishing the line of demarcation between elements that were in the domain of impairments and those that were in the domain of disabilities (Stephens & Hétu, 1991). For example, the inability to detect a 1000-Hz pure tone presented at 40 dB HL via loudspeakers in an audiometric test booth may be taken as a measure of hearing impairment. Does the inability to detect complex tonal signals such as an FM signal centered at 1000 Hz (e.g., a signal that resembles an ambulance warning signal) in the same test setting constitute a measure of impairment or disability? Some professionals considered performance on a speech perception test administered in noise as a measure of impairment (a diagnostic sign of a cochlear hearing loss), whereas others considered the performance on the same task a measure of hearing disability (Stephens & Hétu, 1991). Similarly, there was some confusion between what was considered a disability and what was considered a handicap. For example, does having difficulty understanding speech on the telephone constitute a hearing disability or does it constitute a handicap?
Over the years, some shortcomings of the ICIDH model were identified. For example, according to Figure 3–1, which represents a schematized representation of the ICIDH, the model is unidirectional (Frattali, 1998; Threats, 2006). Specifically, disorders may lead to impairments, which may lead to disabilities. Furthermore, according to the model, impairments and disabilities may lead to handicaps. However, the model does not account for situations whereby disabilities may lead to impairments or where handicaps may lead to disabilities or impairments. In some circumstances, those possibilities may occur. For example, someone may have a hearing impairment (elevated hearing detection thresholds), which may lead to hearing disabilities (e.g., understanding speech in quiet and in noise). The hearing disability may lead to a social integration handicap—because of the difficulties associated with understanding speech, the person avoids social interactions with others. Over a period of time, the social integration handicap (staying at home alone, isolating oneself from others) may bring the person to suffer from psychological depression. How does the ICIDH model account for this situation? In this instance, some people may claim the depression constitutes a secondary handicap (Stephens & Hétu, 1991). Others would report that the handicap (social isolation) led to the development of a new disorder; namely, depression.
Another criticism of the ICIDH model was that some elements known to influence disabilities and handicaps could not be accounted for in the ICIDH framework. A case in point, it has been demonstrated that the physical and social environment are involved in the handicap creation process (Fougeyrollas, Bergeron, Cloutier, Côté, & St. Michel, 1998; Fougeyrollas & Majeau, 1991; Noble & Hétu, 1994). For example, it is well known that the physical environment (e.g., noise, reverberation, and poor illumination) will influence the magnitude of disability and handicap experienced by people with a sensorineural hearing loss. The social environment may also alter the degree of handicap experienced by an individual. For example, to minimize a leisure-related handicap, it would be acceptable for someone with a hearing loss to ask conversational partners to take turns and speak one at a time when playing bridge to optimize the ability to understand speech. However, socially, it is less acceptable to make the same request (asking the people who are sitting close by to speak one at a time) at a large sporting event such as a football game. Recognizing the intricate interaction between the person with hearing loss and the physical and social environment in which a specific activity or event takes place, Noble and Hétu (1994) proposed that the concepts of hearing disability and handicap always be considered within an ecologic approach. Specifically, they described how a handicap should be defined according to the interaction that exists between the person and the environment. As illustrated in an abovementioned example, the disabilities and handicaps experienced by Natasha, the school crossing guard, are situation specific and contextually determined. Investigators in other rehabilitation disciplines also recognized the importance of the environment in describing disability and handicap (Fougeyrollas et al., 1998; Fougeyrollas & Majeau, 1991; WHO, 1997, 1999, 2001).
The International Classification of Functioning, Disability, and Health
After exploring different variations of conceptual frameworks (WHO, 1997, 1991, 2001), the WHO formally proposed a revised classification system: the International Classification of Functioning, Disability, and Health, most commonly referred to as the International Classification of Functioning or ICF (WHO, 2001). This classification system can be applied to all rehabilitation sciences, and is accepted and recognized internationally (e.g., Peterson, 2005; Peterson & Rosenthal, 2005; Smiley, Threats, Mowry, & Peterson, 2005; Threats & Worral, 2004). Thus, an important advantage of the ICF (WHO, 2001) is that it can be used to compare the results of rehabilitation research as well as aspects of clinical services across disciplines and across countries. Like its predecessor, the ICF (WHO, 2001) changes how intervention services are conceived, organized, and dispensed. Given the importance of this classification system, a description of the model follows.
The overall aim of the ICF (WHO, 2001) is to provide a common framework for describing health-related states and, specifically, for understanding the dimensions of health and functioning in all domains of health. The main elements of the ICF (WHO, 2001) are displayed in Figure 3–2 and defined in Table 3–2. The ICF has two parts, each with two components that can be expressed both in positive and in negative terms. The first part incorporates aspects of functioning and disability. This part includes body functions and body structures as well as activities and participation. The second part includes contextual factors, specifically environmental factors and personal factors. According to the ICF (WHO, 2001), an individual’s state of health is determined by the dimensions of functioning and disability and is moderated by how these dimensions interact with each other. The schematic representation of the model indicates that the dimensions of health (body functions and body structures; activities and participation) may influence one another. The model also indicates that contextual factors, such as environmental and personal factors, may influence the dimensions of health. Over the years there has been a modification in how the ICF is applied. Formally, the classification system clearly delineates the domain of activity and activity limitations from the domain of participation and participation restrictions. In some cases, it may be difficult to determine whether a given behavior falls within the purview of activities or participation. Delineating what constitutes an activity from what constitutes participation in an activity can be an interesting but difficult and tedious academic exercise. More importantly, for rehabilitative purposes there is no real advantage of trying to identify behaviors as activities or participation. Typically, individuals with hearing loss experience difficulties when they are executing certain activities that involve hearing (e.g., discussion, remunerative employment, socializing, etc.).
Figure 3–2. Illustration of the interactions of the concepts incorporated into the International Classification of Functioning, Disability, and Health (WHO, 2001).
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