There are two black boxes. One is Pandora's, stuff of myth and legend, and remembered for releasing into the world all its cares and troubles, leaving only hope behind in the bottom of the box. The other, more recent and less mythical, is the in-flight recorder, used to monitor the events in an aircraft's flight, for later analysis in case of difficulty. Both these boxes have their analogy when we consider the role and current state of rehabilitation research in physiotherapy.

Being able to perform physically at a level which ensures a satisfying and independent life is taken for granted in youth, but it comes under threat as physical capabilities deteriorate with advancing age. An independent lifestyle requires muscle strength, muscle power, cardiorespiratory endurance, as well as balance and motivation. It used to be assumed that deterioration in these capabilities with the passage of time in later life was inevitable. Now it is clear that much of the deterioration is due to reduced levels of physical activity. This means that it can be reversed. If physical activity increases so do physical capabilities, even in extreme old age.

Like other organs in the body, the kidneys undergo age-associated anatomical, structural and physiological changes. Starting at 50 years of age, there is a 3-10% decline in kidney weight for each subsequent decade of life, with the loss of cortical mass greater than medullary mass. In fact, the number of glomeruli start to decrease progressively after age 40, and the number of sclerotic glomeruli increases, making the distinction between involutional and disease-related sclerosis unclear in some cases. The outer cortical glomeruli are, in general, more extensively involved than deeper glomeruli, but glomerular size does not change. In general, the loss of the glomerular mass is proportional to the loss of tubular mass, maintaining glomerulotubular balance. In addition to glomerular sclerosis, there is a gradual increase in interstitial fibrosis, and there is focal thickening of both glomerular and tubular basement membranes, probably due to the accumulation of type IV collagen.

Falls and funny turns are very common in old people, and many clinicians feel at a loss as to how to deal with them. Over the past few years, there have been important advances in our understanding of the causes of falls and how best to manage these in the vulnerable elderly population. Given the magnitude of the problem, it is important that such research finds its way into clinical practice.

The problems of undernutrition, weight loss and feeding difficulty are more prevalent in elderly people than in their youngercounterparts and are particularly prevalent in patients with dementia. These aspects of dementia challenge several members of the multidisciplinary team caring for elderly people with dementia, including geriatric and psychogeriatric physicians, dietitians and nurses.

Chronic obstructive pulmonary disease (COPD) is the fifth leading cause of mortality in the USA. For 1984 to 1993, among Canadian seniors aged over 65, COPD was the fourth cause of mortality in men and the seventh in women. Though the underlying pathology is initially confined to the lungs, the associated physical deconditioning and the emotional responses to chronic respiratory disease contribute greatly to the resulting morbidity. Increased shortness of breath leads to inactivity and consequent cardiorespiratory and muscular deconditioning, which in turn leads to further inactivity, social isolation, fear of dyspnoea and depression. Respiratory rehabilitation may offer a way to break this vicious circle.

The ability to differentiate science from science fiction might be considered an essential quality in those who stand on their soapboxes to proclaim the virtues of particular therapies. Not so the protagonists of electrotherapy. It is difficult to think of any treatment modality which until recently has been so neglected by the purists. This is reflected in the plethora of literature churned out on the subject, much of which relates to 'back street' studies which are woefully short on science and method.

Complementary medicine (CM) can be defined as 'diagnosis, treatment and/or prevention which complements mainstream medicine by contributing to a common whole, by satisfying a demand not met by orthodoxy or by diversifying the conceptual frameworks of medicine'. It has become a hotly debated subject, mostly because many physicians remain sceptical about its usefulness while consumers vote for it with their feet and their purses.

Since pronounced aging of the population became evident in the 1976 Australian census, there have been repeated expressions of concern about the health care costs associated with this trend. The latest of these has come from the National Commission of Audit (NCA) which was established by the newly elected conservative Commonwealth Government in June 1996 to undertake a wide-ranging review of the financial position of the Commonwealth Government. The Terms of Reference on which the NCA was to report included 'the impact of demographic change on Commonwealth finances, with the intention of making recommendations as to how emerging pressures could be provisioned'. Many of the themes canvassed in its report are in common with those raised in analyses of the implications of aging for health care costs in other countries, but some reflect particular characteristics of the Australian aged care system and social policy context.

One of the greatest challenges of medicine in old age is for physicians to understand the process of aging and to be able to distinguish it from disease, lifestyle factors and environmental exposures whose cumulative effects account for many of the changes observed in older people. As a result, physicians have a duty to recognize and intervene appropriately against age-related diseases.