Understanding and investigating the quality of life of people with communication disabilities is particularly challenging, as few people beyond the person, his/her family, and the speech pathologist identify and experience the power that communication contributes to life quality. Communication is implicated in relationships, personal development, identity, and social interactions, and has been perceived by clients and clinicians as having a primary role in life. Society has overlooked the importance of communication because of a focus on body, health and functioning. Three factors have deterred inquiry into quality of life investigation with people with communication disabilities: the lack of a sound theoretical and socially valid definition of quality of life, as it relates to communication and disability; the lack of appropriate assessment tools; and the perceived barrier of communication disability to the evaluation process. It is precisely the relationship between communication and quality of life, and the suitability of using significant others as proxy respondents for obtaining quality of life information, which are the foci of the research described in this thesis.
Two population groups were chosen to investigate the relationship of communication to quality of life: older people with aphasia (pathological communication change) and healthy older people (normal communication change). Communication in aphasia and healthy ageing was conceptualised as impairment, activity and participation, in accordance with the disability framework of the World Health Organisation, the International Classification of Impairment, Activity and Participation Revised. Quality of life was evaluated by personal descriptions and global rating, as well as using standard assessments of health-related quality of life and psychological well-being.
In order to examine the relationship between communication and quality of life, 30 older participants with predominantly mild to moderate aphasia and 75 healthy older people were interviewed and assessed. For both groups, participants' communication was associated with their social health and psychological well-being, however age, emotional health and physiological and functional health exhibited powerful influences over the relationships. In aphasic participants, functional communication ability and language functioning to a lesser degree, were implicated in their quality of life, while social participation and communicative activities were more important to healthy older people. Naming, vision and hearing functioning were also associated with healthy participants' health-related quality of life, suggesting that health remains a primary concern in an ageing population.
The research provided substantial evidence that older people's communication relates to being actively involved in conversation, reading and writing; that family and friends are essential in communicative and socially active lives; and that leisure activities are important social components in ageing. Contrasted with healthy older people, aphasic participants had restricted and unsatisfying communicative and social lives, with fewer social contacts. Overall, the results of interviews suggested that communication in life is interpreted as activities and social participation, that communication is more important in the aphasic than healthy population, and that communication is valued more by people who experience aphasia, and naming and hearing impairments.
Collectively, family members and friends were poor judges of older people's quality of life, having only fair to moderate agreement with participant responses. Proxy respondents were better at estimating objective quality of life domains, such as physical health, than subjective domains such as pain, vitality and emotional health. Living with participants, providing emotional support, and knowing the participant for a length of time generally increased proxy reliability for some subjective life quality domains. Proxy respondents for aphasic people were considerably worse than their counterparts with up to 38% less agreement than proxies for healthy people. Proxy respondent depressive symptoms, communication barriers, different perceptions of functioning, and altered life priorities were proposed as reasons for this further discrepancy in ratings in aphasia.
The implication of this research from a clinical perspective is that aphasia rehabilitation needs a multidisciplinary approach, including speech pathologists, counsellors, social workers and physiotherapists in assessment and intervention, and needs to concentrate on people's activities and reduce disability as a means of improving their quality of life. The findings indicate that quality of life is influenced by people's emotional and physical health as much as it is determined by their communication. From a theoretical perspective, communication was associated with social participation and psychological well-being, and physical functioning was relevant for people with concomitant physical disability. Conversely, healthy older people's quality of life constituted both health and well-being. The relationship between communication and quality of life is stronger for people with aphasia, suggesting that communication becomes important when loss is experienced. From a socio-political perspective, the results imply that communication is a devalued determinant of social participation and quality of life, and calls for attitudinal changes at a community level. Society's focus on the primacy of health restricts quality of life to a solely health-related concept. Communication is thus excluded and its importance is not recognised. This view needs to be altered so that speech pathologists can demonstrate how communication rehabilitation for clients relates to achieving and maintaining a satisfying quality of life.