Quality of Life Research (2005) 14: 867–874
Springer 2005
Medical technologies, nonhuman aids, human assistance, and environmental factors in the assessment of health states Yukiko Asada Department of Bioethics, Dalhousie University, Halifax, Nova Scotia, Canada (E-mail:
[email protected]) Accepted in revised form 22 June 2004
Abstract Researchers have developed various health state measures to capture the value of living well. They have reached a consensus that health state measures focus on functionality and general symptoms. One can assess functionality and general symptoms with or without medical technologies (for example, medication, laser surgery, or a pacemaker), nonhuman aids (for example, glasses or a wheelchair), human assistance (for example, the help of another person), and accommodating environmental factors (for example, a barrier-free physical environment). Researchers have paid little attention to these distinctions. In this paper, I discuss why such distinctions are important and explore what implications they have for the construction and application of health state measures. I use the Health Utilities Index Mark 3 (HUI) and the health state measure in the World Health Survey (WHS) as examples of pioneer measures that explicitly acknowledge different levels of functionality and general symptoms. I conclude that the inclusion of medical technologies and nonhuman aids in the assessment of health is reasonable, but not human assistance or accommodating environmental factors. While this conclusion is in line with the HUI and WHS, I discuss a rationale for this boundary and make further suggestions regarding scoring of health states. Key words: Health status, Health Utilities Index, Measurement, Quality of life, World Health Survey Abbreviations: DALY – Disability-adjusted Life Year; HALex – Health and Activity Limitation Index; HIV – human immunodeficiency virus; HRQOL – health-related quality of life; HUI – Health Utilities Index; ICF – International Classification of Functioning, Disability and Health; WHS – World Health Survey
Introduction In our appreciation of health, we value both living long and living well. To capture the value of living well, researchers have developed various measures that assess general health states, generically called health state measures. They include but are not limited to: the Health Utilities Index (HUI) [1–3], EQ-5D [4, 5], the Health and Activity Limitation Index (HALex) [6, 7], and the health state measure in the World Health Survey (WHS) [8–10]. These health state measures all focus on functionality (for example, physical, social or role, and cognitive functions) and general symptoms (for example, pain, energy or vitality, emotion, and senses) rather
than specific diseases or conditions [11, p. 46]. While they vary according to the dimensions of functionality and general symptoms included for assessment, researchers have reached a consensus that functionality and general symptoms are the right focus for attempts to quantify a variety of possible health states between dead and full health [11]. One can assess functionality and general symptoms with or without medical technologies (for example, medication, laser surgery, or a pacemaker), nonhuman aids (for example, eye glasses or a wheelchair), human assistance (for example, the help of another person), and accommodating environmental factors (for example, a barrier-free physical environment). These distinctions are
868 important because they could change the assessment of health and touch on the fundamental question of what health is. However, researchers have paid little attention to these distinctions in the development and application of health state measures. In this paper I discuss why such distinctions are important and explore what implications they have for the construction and application of health state measures. To illustrate the issues I raise in this paper, I start with a hypothetical case. Mai was born to a poor family in rural Cambodia. At the age of five, she became a victim of a landmine. The landmine blew off one of her arms and paralyzed her two legs. Because her family were farmers living in a poor rural area, they could not afford an artificial arm for her and could only occasionally borrow an old wheelchair from a community assistance center. Mai’s physical activities totally depended on the help of her family members, who were usually very busy earning their livings in whatever ways possible. At the age of 10, Mai was adopted by a wealthy Japanese couple. Upon moving to Japan, an artificial arm and an electric wheelchair ensured her mobility, although she still required human assistance for many daily activities, including getting in and out of the wheelchair. Mai’s cheerful nature and intelligence flourished in her new life in Japan, and her new parents were loving and wealthy. Her life in Japan was nevertheless still tough. She always needed to fight to study in a ‘normal’ school for ‘normal’ children, could seldom use public transportation, and was careful about which restaurants ‘accepted’ her as a welcome customer. Frustrated by social barriers encountered in Japanese society, at the age of 19 Mai moved to Berkeley, California, the birthplace of the disability movement in North America. Here her opportunities dramatically expanded. The city provided the personalized human attendant and accessible public transportation so she could live independently, while the university warmly accepted her simply as a hardworking student. Is Mai’s health different in Cambodia, Japan, and the US? Leaving aside obviously important cross-cultural issues, let us assume the legitimacy of using the same health state measure to assess
Mai’s health in three different countries. Should we assess Mai’s health with or without an artificial arm, an electric wheelchair, societal support, and the accommodating physical environment?
A model and problem statement Mai’s case permits us the opportunity to measure functionality and general symptoms at different levels. Drawing from the existing literature [1, 10, 12, 13], I identify five levels of functionality and general symptoms (Table 1). The first level is ‘bare’ functionality or general symptoms that involves no medical technologies and nonhuman aids. The ‘bare’ vision of a shortsighted person, for example, is the vision level without glasses. After becoming a victim of a landmine, Mai’s ‘bare’ mobility is her mobility with two paralyzed legs. The second level is functionality and general symptoms with medical technologies that aim at physiological changes [10]. I broadly use the term ‘medical technologies’, including such medical interventions as surgery, gene therapy, behavioral counseling, and medication, and such a medical device as a pacemaker. Should one focus on this level of functionality, one would measure, for example, the vision level of a shortsighted person after laser surgery, and the functionality of a person with HIV receiving antiretrovirals. In Mai’s case, nowhere are medical technologies currently available to regenerate a lost arm or revive paralyzed legs. The third level is functionality and general symptoms with nonhuman aids. Nonhuman aids do not change human physiology but aim to improve functionality and general symptoms [10]. Examples of human aids include glasses, a hearing aid, a wheelchair, and artificial arms. Mai’s functionality in Japan and the US at this level is her functionality with an artificial arm and a wheelchair. The fourth level is functionality and general symptoms with human assistance. Human assistance is the help of another person provided either informally (for example, by family members) or formally (for example, by a personal care attendant service). Access to human assistance depends
869 Table 1. Functionality and general symptoms at five levels Level
Description
Example
1
‘Bare’ functionality and general symptoms
Mobility with two paralyzed legs Vision with no glasses, contact lenses, and laser surgery
2
With medical technologies
Surgery Gene therapy Behavioural counselling Medication Pacemaker
3
With nonhuman aids
Glasses Contact lenses Hearing aid Wheelchair Artificial arms
4
With human assistance
Human attendant
5
With accomodating environmental factors
Barrier free physical environment Newspapers with large fonts
both on individual and societal resources. In addition, such nonmaterial factors as societal support, acceptance, culture, and tradition affect the use of human assistance. In Cambodia, Mai could not afford human assistance primarily due to the lack of resources of her family and society. The lack of human assistance to her in Japan, on the other hand, was more to do with the social acceptance of people with disabilities rather than the lack of resources. Finally, the fifth level of functionality and general symptoms include accommodating environmental factors. Similar to human assistance, accommodating environmental factors depend on the resources and nonmaterial factors of a society. A farsighted person, for example, could read newspapers with large fonts without glasses. Mai could move around more widely in the US than Japan because of the barrier free physical environment in the US. Using the model I offered above, one can summarize Mai’s health as follows. After becoming a victim of a landmine, her ‘bare’ functionality and general symptoms in Cambodia, Japan, and the US were the same. No medical technologies that change her physiology existed in any of these three countries. Nonhuman aids improved her health in Japan. Human assistance and accommodating environmental factors further improved her health in the US.
Which level of functionality and general symptoms should health state measures assess? Should they only assess ‘bare’ functionality and general symptoms (level 1)? Or should they assess functionality and general symptoms with medical technologies (level 2), nonhuman aids (level 3), and human assistance (level 4)? Should health state measures also pay attention to environmental factors specific to the person being assessed (level 5)?
Existing health state measures and different levels of health In this section I look at how existing health state measures deal with different levels of functionality and general symptoms. I use two examples of health state measures: the HUI Mark 3 (hereafter called the HUI) and the health state measure in the WHS (hereafter called the WHS). It is not my intension to provide a systematic review of existing health state measures. I selected these two measures as pioneers that explicitly acknowledge, and provide conceptual discussion of, different levels of functionality and general symptoms. The HUI The HUI assesses eight dimensions of functionality and general symptoms: vision, hearing, speech,
870 ambulation, dexterity, emotion, cognition, and pain [1, pp. 494–495]. According to its developers, the HUI aims to measure ‘within-the-skin’ experiences and to separate health from any assessment of social interaction [1, p. 491]. The concept of the ‘within-the-skin’ experiences derives from the work by Ware and his colleagues, who explain: In a model of health status at an individual level, physical and mental variables are similar in that they ‘end at the skin’. They do not directly involve other people or factors outside the individual. By contrast, social functioning extends the concept of health beyond the individual to include the quantity and quality of social contacts and social resources [13, p. 621]. Although ‘within-the-skin’ and ‘end at the skin’ give slightly different connotations, following the description by Ware and his colleagues, the dividing line is between level three and four in the model above. ‘Bare’ health (level 1) with medical technologies (level 2) and nonhuman aids (level 3) are within the assessment of health, while human assistance (level 4) and accommodating environmental factors (level 5) are not. How does the HUI questionnaire reflect the concept proposed by Ware and his colleagues? The HUI questionnaire does not ask about the use of medical technologies, by implication presuming their inclusion in the questions. Compatible with
the concept by Ware and his colleagues, the HUI questionnaire explicitly asks questions about the use of nonhuman aids (glasses and contact lenses in vision, hearing aids in hearing, walking equipment and wheelchairs in ambulation, and special tools in dexterity) and assesses health states with these nonhuman aids. The HUI questionnaire also asks questions about the use of human assistance (ambulation and dexterity). Inconsistent with the concept by Ware and his colleagues, it includes health states with human assistance in the assessment of health. The HUI questionnaire does not ask about environmental factors. The HUI scoring system penalizes the use of a nonhuman aid in all four dimensions that acknowledge nonhuman aids. A concrete example illustrates this point. Table 2 lists levels of vision and corresponding health-related quality of life (HRQOL) scores (single-attribute) in the HUI. As Table 2 shows, the HUI assigns a lower score for someone who is able to see well enough to read ordinary newsprint and recognize a friend on the other side of the street with glasses (0.95, level 2) than for someone who can do so without glasses or contact lenses (1.0, level 1). How does the HUI measure the ambulation level of Mai as a landmine survivor? Because the ambulation dimension in the HUI is specifically about walking, Mai’s ambulation level would consistently be level six, cannot walk at all, in Cambodia, Japan, and the US.
Table 2. The Health Utilities Index (HUI) Mark 3 vision Level
Single-attribute utility function
Description
1
1
Able to see well enough to read ordinary newsprint and recognize a friend on the other side of the street, without glasses or contact lenses
2
0.95
Able to see well enough to read ordinary newsprint and recognize a friend on the other side of the street, but with glasses
3
0.73
Able to read ordinary newsprint with or without glasses but unable to recognize a friend on the other side of the street, even with glasses
4
0.59
Able to recognize a friend on the other side of the street with or without glasses but unable to read ordinary newsprint, even with glasses
5
0.38
Unable to read ordinary newsprint and unable to recognize a friend on the other side of the street, even with glasses
6
0
Unable to see at all
871 Table 3. Health state descriptions, vision, World Health Survey Do you wear glasses or contact lenses? (If Respondent says YES to this question, preface the next 2 questions with ‘‘Please answer the following questions taking into account your glasses or contact lenses’’.) (1) Yes (2) No In the last 30 days, how much difficulty did you have in seeing and recognizing a person you know across the road (i.e. from a distance of about 20 m)? (1) None (2) Mild (3) Moderate (4) Severe (5) Extreme/cannot do
The WHS The WHS assesses dimensions of mobility, self care, pain, cognition, interpersonal activities, vision, sleep and energy, and affect [14]. The WHS bases its concept on the International Classification of Functioning, Disability and Health (ICF) [10, 12]. The WHO researchers provide insightful discussion regarding different levels of functionality and general symptoms [10]. They argue that the distinction between medical technologies and nonhuman aids is ‘‘inappropriate’’, because such a distinction ‘‘would omit many health system interventions that are commonly perceived to improve health’’ [10, p. 305]. They state: The distinction we propose here leaves us with personal interventions (drugs, implanted devices, external devices and aids) that improve capacity in a health domain and are available to individuals in the wide range of environments that they are likely to encounter, i.e., interventions that are essentially within individual control rather than environmentally determined [10, p. 305]. As to the environmental factors, ‘‘in the interest of comparability’’ the WHO researchers opted to assess health states by ‘‘a single global standard’’ rather than the environment within which a respondent lives [10, p. 305]. As in the HUI, the distinction dividing the measurement boundary is level three and four in the aforementioned model. The WHS questionnaire does not ask about medical technologies.
The only nonhuman aids mentioned in the WHS questionnaire are glasses and contact lenses in the vision dimension. It is unclear how the WHS questionnaire reflected the concepts of human assistance and the environmental factors. The WHS does not specifically ask about human assistance in each dimension, but, at the beginning of the questionnaire, the WHS asks: ‘‘please answer this question taking into account any assistance you have available’’ [14]. The WHS does not mention about environmental factors, but, again, at the beginning of the questionnaire, the WHS states: ‘‘… while doing the activity in the way that you usually do it’’ [original emphasis 14]. The WHS score is currently under development and not yet available [15]. Judging from the questionnaire, unlike the HUI, the WHS does not penalize the use of nonhuman aids. Questions in the vision dimension proceed as in Table 3. The WHS first identifies the use of glasses or contact lenses. It then asks the same question about vision regardless of the use of glasses or contact lenses. The WHS treat users and nonusers of glasses and contact lenses as identical. Based on the intended concept and construct of WHS, Mai’s mobility was worse in Cambodia than in Japan and the US, but the same in Japan and the US.
Implications for health state measures Why should we be concerned about different levels of functionality and general symptoms in the construction and application of health state measures? Mai’s case demonstrates that the assessment of the same functionality and general symptoms would differ depending on at which level one looks at them. When health state survey questions are ambiguous about which level of functionality or general symptoms they are enquiring, the decision on the inclusion of medical technologies, nonhuman aids, human assistance, and environmental factors in the assessment of health is inevitably left to the respondents. Just looking at answers, researchers would not know what factors respondents decided to include or exclude. Even using the same health state survey, then, researchers may, without recognizing it, be assessing ‘bare’ health at one time and ‘bare’ health with aids or assistance at another time. The preceding discussion, at the
872 very least, suggests that researchers need to decide what they want to measure and develop a health state measure that reflects their decision. The HUI and the WHS are examples of health state measures that explicitly acknowledge different levels of functionality and general symptoms. Yet, neither of them applies their chosen concepts consistently to their health state questionnaires. For example, the HUI’s concept of separating health from the assessment of social interaction does not support the inclusion of human assistance in the assessment of ambulation and dexterity. The WHS questionnaire only mentions glasses and contact lenses as nonhuman aids, whereas the HUI also mentions walking equipment and wheelchairs in the mobility dimension. Neither the HUI nor the WHS explicitly asks about use of medical technologies. Can one always assume that respondents of the HUI and WHS surveys assess their health with, for example, medication or a pacemaker? Even if the questionnaires perfectly reflected the chosen concepts, the HUI and the WHS would assess the health of the same person differently. Mai’s mobility level, for example, would be different according to the HUI and the WHS due to different definitions of mobility. The HUI asks about walking, while the WHS moving around. Researchers using a health state measure should pay attention to how the questionnaire reflects the chosen concept.
What should health state measures assess? Both the HUI and the WHS agree that the assessment of health should include medical technologies and nonhuman aids. The boundary that the HUI and the WHS set out is the individual. Things that can be within a person or move with a person are within the assessment of health. I agree with their decision on setting the boundary at the individual for two reasons. First, the focus on the individual maintains a unique feature of health that each individual has a distinct health experience. Second, the focus on the individual is appropriate in the light of a widely shared understanding of health: health as a multipurpose resource useful for any life plan [16, 17]. Health as a resource belongs to a person. If we were to include social interactions in health measurement,
the point of being concerned about health as a resource belonging to an individual would be lost. In addition, health as a basic, multipurpose resource implies universality. Thus, as the WHS researchers argue [10, p. 305], one should assume functionality and general symptoms in the standardized environment rather than a specific environment in which a respondent is living. One possible objection to the inclusion of medical technologies and nonhuman aids in the assessment of health is that they may jeopardize international or longitudinal comparison of health states. If two populations were vastly different in terms of medical and technological development, the availability of medical technologies and nonhuman aids could greatly affect the assessment of health states. Is this a problem? I think not. Even basic health statistics, such as life expectancy and infant mortality, are not free from medical and technological development. We do not adjust these basic health statistics for the level of medical and technological development of countries where we obtain the statistics. Similarly, we do not need to worry about the effect of the medical and technological development on health states. Availability of medical technologies and nonhuman aids is part of the determinants of functionality and general symptoms. Setting the boundary between level three and four, how best can researchers construct health state measures? It is beyond the scope of this paper to give a full account of the construction of health state measures. Here I discuss only two issues. First, an ideal health state measure would be decomposable by medical technologies and nonhuman aids. For example, a decomposable health state measure would not only assess the vision of the shortsighted after laser surgery or with glasses or contact lenses but also identify how much of the vision is attributable to laser surgery, glasses, or contact lenses (Figure 1). An ideal questionnaire would then ask questions about functionality and general symptoms with and without medical technologies and nonhuman aids, and identify what medical technologies and nonhuman aids a respondent uses. The practicality of this proposal needs further examination. Nonetheless, decomposition is attractive because in a world of limited resources we would be interested in knowing how a certain level of functionality and general symptoms are realized and at what cost.
873 symptoms. Despite the availability of laser surgery, for example, most people rely on glasses or contact lenses to improve vision. The wider use of glasses or contact lenses reflects consideration of such various factors as safety, effectiveness, cost, and convenience. One way to investigate the best way to improve health is to conduct cost-effectiveness analysis. To do so, we need to assess the effectiveness using the same scale for all alternatives as Figure 1 illustrates. With the HUI in the current form, it is difficult to conduct a fair cost-effectiveness analysis for medical technologies and nonhuman aids.
HRQOL score
1
0
‘Bare’ vision
After laser surgery
With glasses or contact lenses
Figure 1. Assessment of the vision of the shortsighted. A shortsighted person can improve the vision by laser surgery or using eye glasses or contact lenses. An ideal health state measure would be able to identify how much improvement is attributable to laser surgery, glasses, or contact lenses, and give the same score for the same improvement brought by medical technology (in this example, laser surgery) and nonhuman aids (in this example, glasses or contact lenses).
The second issue relates to the scoring system of health state measures. Should a health state measure assign the same score for the same function level regardless of the use of medical technologies or nonhuman aids? The WHS does so, but the HUI does not. I support the WHS’ procedure. Recall that the HUI penalizes the use of nonhuman aids. The HRQOL score for someone with good vision without laser surgery, glasses, or contact lenses is 1.0 (Table 2). Assuming laser surgery as a ‘within-the-skin’ experience, the HRQOL score for someone with the same good vision after laser surgery would also be 1.0. However, the HRQOL score for a user of glasses or contact lenses with the same good vision would be 0.95. By penalizing the use of nonhuman aids, the HUI implies that ‘bare’ health and ‘bare’ health with medical technologies are equally good and they are better than ‘bare’ health with nonhuman aids. A reason for the penalty may be that one can lose, forget, or break nonhuman aids. However, what is the best way to improve health is a social policy question that requires examination. We do not always prefer medical technologies to nonhuman aids to improve functionality or general
Conclusion In this paper I discussed the importance and implication of medical technologies, nonhuman aids, human assistance, and accommodating environmental factors in the assessment of functionality and general symptoms. I concluded that setting the boundary at the individual is appropriate, and the inclusion of medical technologies and nonhuman aids in the assessment of health is reasonable. While my conclusion is in line with the HUI and the WHS, I discussed a rationale for the inclusion of medical technologies and nonhuman aids in the assessment of health and made further suggestions regarding the HRQOL scoring. This paper has at least three limitations. First, I treated similarly all different dimensions of functionality and general symptoms in my discussion. Further exploration of issues of medical technologies, aids, assistance, and the environmental factors may require different assessment for different dimensions of functionality and general symptoms. Second, I only used examples of the HUI and the WHS. A systematic review of existing health state measures is necessary to investigate how health state measures commonly deal with different levels of functionality and general symptoms. Finally, the question of which level of functionality and general symptoms health state measures should assess ultimately depends on what about health we wish to measure. I introduced a widely shared view of health as a multipurpose resource. My discussion on this point was admittedly shallow, and further exploration is necessary. For example, in a recent series of papers Reidpath,
874 Allotey, and their colleagues provide another view of what about health we should measure [18, 19]. They argue that Disability-adjusted Life Year (DALY) should measure the burden of disease ‘‘as it truly occurs’’ [18, p. 354]. In this view, DALY should include not only medical technologies and nonhuman aids but also human assistance and the environmental factors. The issues explored in this paper are complex, but, I believe, necessary considerations for the further development of health state measures. Acknowledgments I am indebted to Profs David Kindig, John Mullahy, Patrick Remington, Alberto Palloni, Daniel Hausman, and Daniel Wikler for their general assistance for my dissertation, from which this present study was derived. I am also grateful to Profs Nuala Kenny and George Kephart and the reviewers for their helpful comments. This project was supported by grant number 1 R03 HS 13116 from the Agency for Healthcare Research and Quality, and the Canadian Institute of Health Research Training Program for Ethics and Health Policy and Research.
References 1. Feeny D, Furlong W, Boyle M, Torrance GW. Multiattribute Health Status Classification Systems: Health Utilities Index. PharmacoEconomics 1995; 7: 490–502. 2. Feeny D, Furlong W, Torrance GW, et al. Multi-attribute and single-attribute utility functions for the Health Utilities Index Mark 3 system. Med Care 2002; 40: 113–128. 3. Health Utilities Group. Health Utilities Index and Qualityof-life. Available at http://www.fhs.mcmaster.ca/hug/, last accessed May 27, 2004. 4. EuroQol Group. Welcome to the website of the EuroQol Group. Available at http://www.euroqol.org/, last accessed May 27, 2004. 5. Brooks R, The EuroQol Group. EuroQol: The current state of play. Health Policy 1996; 37: 53–72. 6. Erickson P, Wilson R, Shannon I. Years of health life. Healthy people 2000, Statistical Notes 1995; 7: 1–14. 7. Erickson P. Evaluation of a population-based measure of quality of life – the health and activity limitation index (HAlex). Qual Life Res 1998; 7: 101–114.
8. World Health Organization: World Health Survey Home Page. Available at http://www3.who.int/whs/, last accessed May 27, 2004. 9. U¨stu¨n TB, Chatterji S, Mechebal A, Murray CJL, Groups WC. The World Health Survey. In: Murray CJL, Evans DB (eds), Health Systems Performance Assessment: Debates, Methods and Empiricism. Geneva: World Health Organization, 2003: 797–808. 10. Salomon JA, Mathers CD, Chatterji S, et al. Quantifying individual levels of health: Definitions, concepts, and measurement issues. In: Murray CJL, Evans DB (eds), Health Systems Performance Assessment: Debates, Methods and Empiricism. Geneva: World Health Organization, 2003: 797–808. 11. Fryback DG. Appendix C: Methodological issues in measuring health status and health-related quality of life for population health measures: A brief overview of the ‘HALY’ family of measures. In: Field MJ, Gold MR (eds), Summarizing Population Health: Directions for the Development and Application of Population Metrics. Washington, DC: Institute of Medicine, 1998: 39– 57. 12. World Health Organization. International Classification of Functioning, Disability and Health. Geneva: World Health Organization, 2001. 13. Ware JEJ, Brook RH, Davies AR, Lohr KN. Choosing measures of health status for individuals in general populations. Am J Public Health 1981; 71: 620–625. 14. World Health Organization. World Health Survey, short version questionnaire, rotation A. 2000; 2.1–2.2. Available at http://www3.who.int/whs/P/instrumentandrel8293.html, Last accessed May 27, 2004. 15. Salomon JA, Tandon A, Murray CJL. World Health Survey Pilot Study Collaborating Group. Comparability of self rated health: Cross sectional multi-country survey using anchoring vignettes. Br Med J 2004; 328: 258–263. 16. Anand S. The concern for equity in health. J Epidemiol Commun Health 2002; 56: 485–487. 17. Nussbaum MC. Women and Human Development: The Capabilities Approach. Cambridge: Cambridge University Press, 2000. 18. Reidpath DD, Allotey PA, Kouame A, Cummins RA. Measuring health in a vacuum: Examining the disability weight of the DALY. Health Policy Plann 2003; 18: 351– 356. 19. Allotey P, Reidpath D, Kouame A, Cummins R. The DALY, context and the determinants of the severity of disease: An exploratory comparison of paraplegia in Australia and Cameroon. Social Sci Med 2003; 57: 949– 958. Address for correspondence: Yukiko Asada, Department of Bioethics, Dalhousie University, 5849 University Avenue, Halifax, Nova Scotia, Canada B3H 4H7 Phone: +1-902-494-1899; Fax: +1-902-494-3865 E-mail:
[email protected]
