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RESEARCH ARTICLE |
Lighthouse International, Arlene R. Gordon Research Institute, New York, New York.
Address correspondence to Dr. Amy Horowitz, Lighthouse International, 111 East 59th Street, New York, NY 10022. E-Mail: ahorowitz{at}lighthouse.org
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Abstract |
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Methods. We interviewed older adults (n = 438) with a recent vision impairment applying for vision rehabilitation services both pre-service and at the 6-month follow-up. We conducted hierarchical regression analyses with functional disability and depressive symptoms as criteria. In order to identify their independent direct effects, we entered optical and adaptive device use into the final step, preceded by Time 1 criterion scores, demographics, baseline disability or depression (depending on criterion), and total rehabilitation service hours.
Results. Optical, but not adaptive, device use was significantly associated with declines in functional disability and depressive symptoms over time.
Discussion. We propose that these differential effects result from the fact that optical devices optimize residual vision and thus allow for greater continuity in the way tasks are accomplished (i.e., reading still performed visually), whereas use of adaptive aids (e.g., talking books) involves learning new methods in order to compensate for lost functions and thus is not as desirable either functionally or psychologically.
ALTHOUGH older persons who acquire age-related disabilities often depend on personal assistance from family, friends, and formal providers, many also rely on assistive devices in order to accomplish daily activities. Assistive devices are defined as a technology or equipment that is used to maintain, enable, or improve self-managed functional ability to achieve or maintain independence and increase quality of life (Mann, Karuza, Hurren, & Tomita, 1992
; Tomita, Mann, Fraas, & Stanton, 2004). Data from the National Health Interview Survey and Assistive Device Supplement indicate that 23% of older adults in the community use some type of assistive device (Hartke, Prohaska, & Furner, 1998), a figure that represents more than one half of all persons who use assistive devices in order to compensate for a physical disability (La Plante, Hendershot, & Moss, 1992).
Visual impairment, typically resulting from age-related eye disease (e.g., macular degeneration) is one of the most common disabilities of later life. It affects approximately 15% to 20% of adults aged 65 and older and more than one fourth of those aged 75 and older (Crews & Campbell, 2001; Horowitz, Brennan, & Reinhardt, 2005). Most of these older people are not totally blind but retain partial sight or low vision, defined as a permanent vision impairment that is not correctable by refraction or medical–surgical interventions (Raasch, Leat, Kleinstein, Bullimore, & Cutter, 1997). A growing body of evidence points to vision impairment as a major cause of functional disability and future functional decline among older adults (Brennan, Horowitz, & Su, 2005; Burmedi, Becker, Heyl, Wahl, & Himmelsbach, 2002a; Horowitz, 2004). Age-related vision loss is also a major risk factor for depression (Burmedi, Becker, Heyl, Wahl, & Himmelsbach, 2002b; Horowitz 2004; Horowitz & Reinhardt, 2000), and approximately one third of older adults who are visually impaired experience clinically significant depressive symptoms (Brody et al., 1999; Horowitz, Reinhardt, Boerner, & Travis, 2003; Horowitz, Reinhardt, & Kennedy, 2005; Reinhardt, 1996; Rovner & Casten, 2002). Despite the prevalence of age-related vision loss and its negative consequences, research on assistive technology for older adults has paid little attention to how such devices might impact functional and psychological outcomes for individuals with age-related visual impairments. We propose that such research can be guided by prior theoretical work on everyday competence.
Everyday competence is defined as the ability, in later life, to interact effectively with the environment and accomplish tasks that are necessary for independent living by using one's resources in the sensorimotor, cognitive, personality, and social domains (M. M. Baltes & Lang, 1997; Diehl, 1998; Diehl & Willis, 2003; Lang, Rieckmann, & Baltes, 2002; Willis, 1996). It is important to note that competent behavior does not reside solely in the person or the environment, but in their interaction, which determines the ability to meet daily life challenges (Diehl & Willis; Lawton, 1982). The loss of vision, a critical sensory resource, and its resulting effects on function and mental health, reinforces the importance of a person–environment perspective when studying everyday competence in older adults with visual impairment. In fact, Wahl, Oswald, and Zimprich (1999) showed that older adults who were visually impaired, compared with those not impaired, demonstrated a greater tendency to maintain daily competence through particular adaptations such as the optimization of light, reorganization of the physical environment, compensatory use of latent skills (e.g., using touch to tell when cup is full), and use of low vision devices (but not other prosthetic devices). This perspective is consistent with P. B. Baltes and Baltes's (1990) conceptual model of selection with optimization and compensation; that is, selection of the most important goals, optimization of remaining resources, and compensation for lost functions. Furthermore, the use of assistive devices can serve to reduce task demand (Verbrugge & Sevak, 2002) and thus lead to better outcomes, because everyday competence is maintained and protected from further deterioration. Thus, assistive devices represent a type of sensorimotor resource that an older person may utilize to maximize everyday competence within the context of late-life disability.
Studies of Adaptive Device Use by Older Adults
Given the great potential of assistive devices to promote functional independence and improve quality of life for people with disabilities, surprisingly little research has examined the efficacy of device use among older adults. Most prior studies have focused on identifying the personal characteristics that predict device utilization and consistently find that "need" factors (i.e., level of impairment and disability) are the strongest predictors of assistive device utilization (Gitlin, Schemm, Landsberg, & Burgh, 1996; Hartke et al., 1998; Tomita et al., 2004; Verbrugge & Sevak, 2002). The few studies that have examined the impact of assistive devices have primarily focused on functional outcomes and have provided preliminary evidence supporting the efficacy of assistive devices in slowing functional decline (Mann, Ottenbacher, Fraas, Tomita, & Granger, 1999) or improving functional ability (Sonn, 1996; Verbrugge, Rennert, & Madans, 1997; Verbrugge & Sevak, 2002).
Device Use Among Persons Who Are Visually Impaired
Rehabilitation for visual impairment, similar to generic geriatric rehabilitation, seeks to maintain or improve functional status as well as to enhance psychosocial well-being through multiservice interventions. A key component is clinical low vision services, which involve the assessment of remaining visual functions by specially trained ophthalmologists or optometrists and the prescription of optical devices such as magnifiers, telescopes, and special sun wear. Optical devices can be used to assist in many tasks, although they primarily facilitate both near- and distance-reading tasks (e.g., print material or street signs, respectively). Low vision therapists or rehabilitation teachers typically provide training in the appropriate use of the devices following their prescription. The low vision specialist or rehabilitation teacher may also recommend nonoptical, adaptive devices (e.g., talking books, large-print materials, signature guides, talking clocks and appliances) that facilitate the accomplishment of everyday activities.
Although there has been a great deal of interest in evaluating the outcomes of low vision clinical services and optical device utilization, researchers have noted that the evidence base for the effectiveness of vision rehabilitation is only just emerging (Raasch et al., 1997). Definitions of effectiveness vary considerably from specific visual task performance (e.g., reading speed), to functional activities of daily living (e.g., crossing streets, cooking meals), and, less commonly, to more global indicators of psychological well-being and quality of life. Although emerging evidence supports the benefits of low vision services and devices, there are several limitations to the current research. Several studies have relied on postservice subjective measures of patient satisfaction and perceived benefits of optical and/or assistive devices to establish effectiveness (D'Allura, McInerney, & Horowitz, 1995; Hall, Sacks, Dornbusch, & Raasch, 1997; Leat, Fryer, & Rumney, 1994; Scott, Smiddy, Schiffman, Feuer, & Pappas, 1999). Others have focused on frequency and type of optical device use in the community (Davis, Lovie-Kitchin, & Thompson, 1995; Leat et al., 1994; Watson, Beck, De l'Aune, Stelmack, & Maino, 1994; Watson, De l'Aune, Long, Maino, & Stelmack, 1997; Watson, De l'Aune, Stelmack, Maino, & Long, 1997). Some studies have used retrospective reports at postservice in order to identify change in specific functional tasks when preservice data were not available (De l'Aune, Williams, Watson, Schuckers, & Ventimiglia, 2004).
Although some prior studies have reported on pre- and postservice functional measures and have documented gains in task-specific functional ability, often researchers conduct post-tests immediately after the intervention has been completed, thus providing little information regarding more long-term benefits (Stelmack, Stelmack, & Massof, 2002). Furthermore, these studies rarely examine psychological well-being or mental health status as an outcomes, although it has been noted that the goal of rehabilitation is not only to maximize functional ability, but also to instill a sense of control and empowerment that, in turn, has an impact on mental health (Warren & Lampert, 1994). Finally, the focus has been on low vision optical devices with little specific research attention given to the impact of nonoptical adaptive aids used by older adults with age-related vision impairments (e.g., large-print reading materials, talking books, handwriting aids, and long white mobility canes). With skills training in the use of nonoptical aids, older adults with vision loss can regain the ability to accomplish desired tasks (Goodrich, 2003).
We designed the research reported in this article in order to build upon and expand the existing knowledge base in three ways: first, by examining both functional and psychological outcomes of device utilization by visually disabled older adults; second, by examining the association of both optical devices and assistive aids to outcomes; and third, by looking at more long-term outcomes of device utilization. Thus, the primary objective of this research was to determine the extent to which optical devices and adaptive aid utilization significantly contribute to change in functional disability and depression among older adults with age-related vision impairments.
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METHODS |
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) in order to screen for cognitive impairment, and excluded persons with a current diagnosis of Parkinson's disease or history of stroke in the past year due to the physiological link between these conditions and depression. Investigators contacted potential participants by telephone in order to screen for eligibility and, if the elder was interested, to schedule an interview. Participants read and signed an informed consent that had been approved by the organization's Institutional Review Board. We collected data at baseline (Time 1) prior to service utilization and 6 months following baseline (Time 2). Interviews were conducted in participants' homes and took approximately 2 hours to complete. Of 1,052 eligible respondents at baseline, 55.5% (n = 584) participated. Comparisons of respondents and refusals on basic intake data showed that the latter were older, less likely to be married, and more likely to live alone. Of the 584 baseline participants, 78.1% (n = 455) participated in the 6-month follow-up; 11.5% refused to do so; 3.9% had died; and the remaining 6.5% either could not be reached in the time period, were too cognitively or hearing impaired to participate, or had incomplete interviews. There was no significant difference between participants at the 6-month follow-up and nonparticipants on age, race/ethnicity, gender, marital status, living arrangement, level of education, or level of disability in instrumental activities of daily living. However, participants at Time 2 had significantly lower scores on depressive symptoms at baseline (M = 11.7, SD = 10.2) than did individuals who did not participate in the follow-up interview (M = 14.3, SD = 10.4; p <.05). Additionally, a significantly higher proportion of participants than nonparticipants received at least some service following application (91.0% and 83.7%, respectively; p <.05).
For the current analyses, given the small number of participants who were Hispanic or of other races (n = 17), we only included White and African American participants (n = 438). The age of these individuals ranged from 65–99 years at baseline, with a mean of 80.4 years (SD = 7.43). Due to procedures that oversampled men, there was a fairly even distribution of men (46.6%) and women (53.4%). The majority of participants were White (87.2%), and 12.8% were African American. Two fifths (41.1%) were married and more than half (56.2%) lived with others rather than alone. Regarding education, 72% had at least a high school education. Two thirds (69.7%) reported having macular degeneration, 26.8% glaucoma, 37.1% cataracts, and 13.7% diabetic retinopathy. Only 20.5% met the visual acuity criterion for legal blindness (i.e., 20/200 or worse), and almost all had at least some usable vision.
Measures
The Time 2 measures of the following variables comprised the criterion measures of the hierarchical multiple regressions reported later. We used Time 1 scores on these variables as independent covariates in order to control for initial status on these outcomes.
Disability
We assessed functional disability by using a modified version of the Older Americans Resources and Services Multidimensional Functional Assessment Questionnaire (Center for the Study of Aging and Human Development, 1975) and also assessed the older person's disability in 11 instrumental activities of daily living (IADLs). The seven original IADL items were: using the telephone; traveling outside of walking distance; preparing meals; doing light housework; taking medications; writing out checks to pay bills; and shopping for groceries. We added four items that specifically addressed functional tasks that may be affected by vision loss (i.e., getting around in an unfamiliar place; and identifying currency, one's clothing, and food on one's plate). We rated each item on a 4-point scale: 1 (able to do independently with no difficulty), 2 (able to do independently with a little difficulty), 3 (able to do independently with a great deal of difficulty), or 4 (unable to do at all or unable to do without the help of another person). We examined only IADL disability, rather than including personal activities of daily living, because the former tasks are those that are primarily affected by vision impairments and that are the focus of rehabilitative interventions.
Depression
We measured depressive symptoms by using the 20-item Center for Epidemiologic Studies–Depression scale (Radloff, 1977). We rated depressive symptoms (e.g., feelings of worthlessness, psychomotor retardation) on a 4-point scale, ranging from 1 (less than a day) to 4 (5 to 7 days during the past week).
In addition to use of optical and adaptive devices, we included in the analysis as independent covariates other variables that have been identified in past research as influencing functional disability and/or depression.
Sociodemographic factors
We assessed demographic variables with single-item indicators on age, gender, race/ethnicity (White or African American), and education (7-point scale ranging from 1 = less than 7 years to 7 = graduate or professional degree).
Rehabilitation service hours
In order to control for the use of other rehabilitation services on depression and disability over time, we calculated the total sum of rehabilitation service hours received in all programs (i.e., low vision, rehabilitation teaching, orientation and mobility, and counseling services) between Time 1 and Time 2.
Number of optical devices used at Time 2
We asked participants if they used any of the following optical devices: magnifier, telescope, or special sunglasses. In addition, participants could report up to two other optical devices. The most common other devices reported were closed circuit televisions and magnified television screens.
Number of adaptive aids used at Time 2
We asked participants if they used any of the following aids because of their vision loss: large-print telephone dials, handwriting guides, talking books, other talking items, large-print reading material, long white cane for mobility, or other aids. Participants could report up to two other adaptive devices; the most common ones reported were specialized kitchen aids and large-faced watches or clocks.
Descriptive data for the major study variables are presented in Table 1.
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), we entered baseline depression in Step 3. We included rehabilitation service hours in Step 4 in order to control for the intensity of rehabilitation interventions overall (excluding device prescription), and, finally, we entered the number of optical devices and adaptive aids used at Time 2 in Step 5. The second analysis with Time 2 depression as criterion followed the same structure, but with Time 1 depression in Step 1 and baseline disability in Step 3. |
RESULTS |
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). Again, use of optical devices was associated with a decline in depression over time, but there was no such significant relationship for adaptive devices.
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DISCUSSION |
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In order to understand the significance of the relationships between optical device use and decreased IADL disability and depression over time, it is important to note that the psychological distress associated with disability often stems from the impact that the disability has on especially valued activities (Rovner & Casten, 2002). For older adults, losing the ability to read is one of the most devastating consequences of vision loss (Ryan, Anas, Beamer, & Bajorek, 2003). It is a loss that is ubiquitous; not only is pleasure reading affected, but the inability to read newspapers and magazines can psychologically break one's connection with the larger society; difficulty reading menus and materials for religious services may threaten one's connection to social communities; and difficulty reading price labels, street signs, and medicine bottles further contributes to problems with everyday activities (Horowitz, 2004). Because most optical devices specifically target near reading via magnifiers and distance viewing through telescopes, low vision interventions allow these valued activities to be continued and/or resumed with the continued use of vision.
But why did our study findings fail to find similar support for a relationship between adaptive devices and change in disability and depression at follow-up? We offer three possible, but not mutually exclusive, explanations. First, adaptive devices target instrumental activities that are necessary in daily life but are not necessarily valued in the same way as is reading. Second, in the current study, participants who were the most functionally disabled used the most adaptive devices, a finding consistent with research that has examined other disabled populations (Gitlin et al., 1996; Hartke et al., 1998; Tomita et al., 2004; Verbrugge & Sevak, 2002). Thus, given the strong association between disability and depression and the control for baseline disability in both models, the extent of shared variance between disability and adaptive devices may make any independent relationship between adaptive devices and outcomes difficult to identify. However, perhaps the most likely explanation is that people who have the poorest vision have the fewest options for continuing to accomplish tasks visually and often must place greater reliance on adaptive aids that compensate for vision loss rather than optical aids that optimize the use of remaining vision. Hence, there is greater discontinuity in ways of accomplishing daily activities, which in turn involves greater adjustment, greater distress, and more limited potential for functional improvement (Verbrugge & Sevak, 2002). Interestingly, Gitlin (1998) has stressed that when older adults need to take action to maintain everyday competence, they make changes slowly in a stepwise fashion (i.e., they begin with behavioral changes, then possibly introduce adaptive devices, and, finally, make adjustments to the physical environment). This is consistent with our suggestion that older adults with visual disabilities first strive to maintain continuity by optimizing remaining vision (often with the assistance of optical devices) and turn only to learning compensatory techniques with adaptive devices when the former is no longer an option. Furthermore, continuity theory (Atchley, 1989) posits that continuation of previous patterns and activities is a major contributor to successful adaptation in later life. Thus, although application of the model of selection with optimization and compensation (P. B. Baltes & Baltes, 1990) to understanding everyday competence remains relevant, there may also be a hierarchy among these strategies. That is, current findings suggest that different types of assistive devices, based on the extent to which they optimize existing sensory resources or compensate for their loss, may vary in their ability to buffer threat, challenge, and loss to everyday competence as a function of how well they enable task continuity following the onset of significant physical disabilities.
Although not the primary focus of the current analyses, findings from this study also address the longitudinal relationships between depression and disability in later life. We found that baseline level of depression was not associated with change in level of disability at the 6-month follow-up, suggesting that depression did not necessarily lead to excess disability within a group of older adults who received rehabilitation services. Yet, baseline disability did predict change in depression over time. The latter finding suggests that rehabilitative interventions that address disability may indeed have the added benefit of reducing depressive symptomatology over time. However, untangling the complex associations between disability and depression requires the study of multiple time points and the use of varied intervention approaches, including those that separately target people with depression and functional disability, as well as those that target people with both depression and functional disability (Bruce, 2001).
Clinically, our findings clearly support both the functional and psychological benefits of optical device use by older adults with age-related vision impairments. Although we failed to find similar support for adaptive device use, this should not be interpreted as providing evidence for the benefit of one type of assistive technology over the other. Optical and adaptive devices serve different purposes, and they are typically of varying importance for older adults with different levels of visual disability. Older adults may view adaptive devices more negatively because use of these aids requires making major adjustments in the way tasks are performed (e.g., using a long white cane for mobility, talking books for reading, etc.). Thus, it is likely that greater attention to education and counseling, in addition to training, is needed in the rehabilitation process in order to underscore that although these compensatory devices may require greater adjustment, they can be as successful as optical devicesin helping the older adult meet desired goals.
This study adds to the growing body of research that supports the efficacy of assistive devices for older people in general, and of low vision optical devices, in particular, for improving quality of life for the increasing numbers of older adults with age-related vision impairments. Health care policy, however, lags far behind. Although the Medicare Modernization Act of 2004 included a provision for a national demonstration project for covering vision rehabilitation services for older adults in six limited geographic sites across the country, current Medicare policy and most health insurance plans fail to cover the costs of low vision devices. This is especially unfortunate given that many optical devices are relatively inexpensive and most low vision patients require simple, low magnification aids (Leat & Rumney, 1990). Federal health insurance programs now emphasize personal assistance for functional problems. However, Verbrugge and colleagues (Verbrugge et al. 1997; Verbrugge & Sevak, 2002) compared the efficacy of using equipment only with using personal assistance only, and they found that the former group had a higher likelihood of improved functioning. These investigators proposed that assistive devices, which are typically task specific and available upon demand, are more likely to maintain a person's sense of self-sufficiency and efficacy (i.e., competence) when compared with having to rely on the help of another individual. The importance of technological aids in supporting a continued sense of independence and autonomy among older adults with disabilities should not be underestimated in aging network services; it deserves support in current health care and insurance programs.
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Acknowledgments |
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Footnotes |
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Received for publication October 28, 2004. Accepted for publication January 3, 2006.
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This article has been cited by other articles:
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  M. Brennan and S. J. Bally Psychosocial Adaptations to Dual Sensory Loss in Middle and Late Adulthood Trends in Amplification, December 1, 2007; 11(4): 281 - 300. [Abstract] [PDF]
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