Discussion.Especially among visually impaired elderly, dual sensory loss (DSL) is highly common. Of all the related difficulties, communication is perhaps the most challenging and it may negatively affect a patient’s health and wellbeing. We expect the newly developed DSL protocol to reduce these difficulties. This may lead to better hearing aid use, improved use of effective communication strategies and hence, better quality of life, health and wellbeing. This paper describes the ‘Dual Sensory Loss-protocol’ and the design of a multicenter international RCT to determine the effectiveness and cost-effectiveness of the DSL protocol.
In the development of the DSL protocol, designed for OTs working in low vision rehabilitation, we obtained information from the literature, which we complemented with interviews and discussions with patients and professionals (working in ear and eye care). The trial will test the effectiveness of the additional DSL protocol compared to a waiting list control group on use and maintenance of hearing aids; communication; coping with a dual sensory impairment; social participation and quality of life of the patient and communication partner; and cost-effectiveness from a societal perspective.
The development of the protocol and design of the RCT required decisions as to which professionals would be most suitable to perform the protocol, and which DSL patients should be included in the trial.
Firstly, the DSL protocol consists of three chapters suitable for different rehabilitation professionals. On the one hand, the first two chapters of the DSL protocol focus on maximizing use of the senses with the use of hearing aids; other assistive devices; and minor adaptations to the living environment; these are considered highly suitable topics to be handled by OTs. On the other hand, the last chapter focuses on psychosocial issues: it discusses communication difficulties, psychosocial problems, coping with dual sensory impairment, and also teaches communication strategies; some consider that these topics are more suitable for social workers. To be able to build a relationship of trust, the patient can best be handled by one professional, and we decided OTs are the most competent. Secondly, we decided to recruit DSL patients who already received usual low vision and audiology care, i.e. patients who possess hearing aids and who have received low vision rehabilitation. This allows us to investigate the added value of the DSL protocol compared to a waiting list control group (which was allowed to receive other interventions if needed).
Several studies have aimed to meet the urgent need for evidence-based protocols and interventions in rehabilitation [91-94]. However, until now, little attention has been paid to the development and evaluation of interventions for the vulnerable group of DSL patients, who represent an urgent research need [47]. Our innovative study on rehabilitation of DSL for use in low vision rehabilitation is one of the few addressing these needs in older patients with age-related DSL. Additionally, low vision patients who seek help for their impairment at multidisciplinary low vision rehabilitation centers will likely be open to rehabilitation in general. We believe our DSL protocol will assist frail elderly with DSL in low vision rehabilitation; it addresses urgent needs not yet addressed by other interventions.
However, there are limitations to the study concerning both the protocol and the RCT. First, the DSL protocol was developed for patients with some residual vision and hearing, which concerns the vast majority of DSL patients [95], and focuses on maximum use of both senses. Therefore, the protocol is less suitable for totally blind and/or deaf patients; information on teaching tactile sign language is not incorporated. Also, although we believe that the DSL protocol is comprehensive and includes various forms of rehabilitation, eccentric viewing is not included. It maybe worthwhile for future implementation of the protocol to include eccentric viewing strategies to improve speech reading in patients with central scotoma [38]. Other limitations are related to the choice of a pragmatic instead of an explanatory trial. Further standardization of the DSL protocol would increase the ability to adequately evaluate the effectiveness. Standardization of the protocol could be improved by, e.g. standardizing the exact amount of time per exercise and chapter, and the number of sessions per patient. However, in daily practice it is very important to adapt to the needs of the individual patient, e.g. severity of vision and hearing impairment; or other impairments/limitations due to comorbidity, learning abilities, fatigue or concentration. For this reason, the current DSL protocol is adaptive to suit the needs of the individual patient. In line with the suboptimal standardization, the rather heterogeneous study population could be another limitation. However, to ensure generalizability, the study population had to reflect the variations among patients which occur in actual rehabilitation practice and to best represent patients in whom the treatment would be applicable.
Second, due to budgetary restrictions it was not possible to provide information on the long-term effects. Third, blinding of participants and OTs is not possible since no placebo treatment is included in the study to account for the placebo effect. Participants may report change as a result of simply meeting with an empathetic professional each week to discuss problems. Therefore, the effect of the DSL protocol is the total difference between groups, including both treatment and associated placebo effects. This has both advantages and disadvantages: a disadvantage is that the pure effect of the DSL protocol’s content remains unclear whereas, on the other hand, reality is best reflected. This pragmatic trial provides the best reflection of the likely rehabilitation outcome in actual practice.
This study provides useful information on DSL. Also, if the trial shows the DSL protocol to be effective, this will allow multidisciplinary low vision rehabilitation centers to provide an evidence-based treatment protocol for DSL patients. The DSL protocol will be an important tool for OTs to assist their older patients with DSL in the use of hearing aids, to maximize use of the senses, and to teach patients and/or communication partners specific skills to improve communication.
However, DSL needs more attention in other care settings (besides low vision rehabilitation), such as nursing homes and audiology rehabilitation. It is estimated that about 2% of the elderly who consult a hearing healthcare professional experience such visual impairment to such extent, that it limits the perception of facial cues for communication [54]. Although future research on DSL in audiology care is recommended, rehabilitation of DSL in the setting of audiology care requires even more effort. Hearing impairment in the elderly occurs much more frequently than visual impairment. Therefore, DSL in audiology rehabilitation is less common, so that more patients need to be screened to detect patients with DSL. In addition, low vision and hearing rehabilitation is organized in different ways. For example, in the Netherlands, many older adults with hearing loss in the Netherlands do not consult a multidisciplinary audiology rehabilitation center but go directly to a hearing aid dispenser; this occurs much less with low vision.
Besides special treatments for DSL, there is a need for more collaboration between low vision and audiology rehabilitation by, for example, making greater use of referrals [53]. To facilitate this, rehabilitation professionals working in low vision and audiology need interdisciplinary training, to enable them to detect problems associated with DSL and to refer patients as required.
In conclusion, until now, insufficient attention has been paid to the problems of elderly with DSL. However, the development of this DSL protocol represents an important step to improve the health and quality of life of DSL patients