From the simplest cells to complex creatures gifted with language, imagination and creativity, life has a beginning, interims and an ending.
There’s no escape. Good genes, a healthy lifestyle, timely and effective intervention, treatment for threats along the way and luck may put off the inevitable for a while — but in the end, there is an end.
The fact that there is an end, however, is out of sight and mind for most people, except for illnesses and death that affect their parents or grandparents.
Life between birth and the early 30s is spent learning and honing increasingly elaborate motor skills, learning language, how to read the intentions and emotions of others, developing a sense of self-awareness, fitting in with increasingly large, and complex social communities and adopting family, cultural and community norms.
Then come the middle years between the early 30s to the late 60s. This four-decade period is, for the most part, a period of consolidation and continued learning from experience, and like the earlier period, a time when most take for granted good health and adapt to new challenges in the workplace and home with relative ease.
Even so, there are warning signs: MRI studies suggest that during this middle period, the neocortex begins to shrink, even If there are few if any obvious functional correlates.
Physiological studies by Alan McComas at McMaster University in the 1970s suggested that the sixth decade marks the beginning of losses of motor nerve cells in the spinal cord.
If so, there are probably similar losses, affecting other nerve cells in the brain and spinal cord even though studying the latter cells is harder to do.
Losses of nerve cells are accompanied by losses of the connections those cells had with other nerve cells and, in the case of motor nerve cells in the brainstem and spinal cord, with muscle fibres.
Despite these losses, the impact on function may, initially, be minor because surviving related nerve cells manage to cover the functional deficit — until those initial survivors begin to succumb, too.
The period in the 60s and 70s is also marked by the beginnings of degenerative changes including microvascular changes, continued atrophy of the neocortex and other structures in the brain, and for some subjects, the accumulation of malformed proteins in the brain in the form of beta-amyloid and tau – even if there are no relatable symptoms yet.
What sets the 80s apart from the 70s is that degenerative changes and beta-amyloid and tau depositions become common in the brain become common, and clinically significant cognitive and memory changes eventually affect one-third of those in their 80s.
The 80s are also marked by the cumulative impact of other challenges such as the increasing prevalence of deafness, macular degeneration and significant degenerative arthritis in the lower back, hips and knee joints, which coupled with cognitive and memory losses, lead to significant functional disabilities and limit mobility and social activities.
By this time in life, atrophy of the brain is very obvious and marks the loss of large numbers of nerves and other supporting cells in the brain.
The impact of cognitive changes on social activity is very apparent among those with dementia in long-term care facilities.
My observation is that residents with dementia rarely form meaningful relationships with other affected residents, despite living together in the community for many months and even several years.
With social isolation comes a withering of their social and language skills that compounds the problems of isolation. That’s where well-trained and motivated staff can make a big difference by making efforts to talk to individual patients and listen to their responses.
Residents do respond to cheery, literally hands-on staff members, but not so much to group activities.
While it may be useful for clinical purposes to separate the cognitively healthy from those with early signs of dementia, the fact that the percentage of those with dementia continues to rise in the 90s suggests that the spectrum is seamless and that eventually, the majority of those in their 90s will suffer from significant cognitive impairment made worse by social isolation as friends of the same age become similarly affected or die and their social world contracts.
I doubt there will be a truly effective drug for dementia anytime soon and given that most people have developed several impairments that limit their quality of life in the last two decades, it’s important that the province plan for far more creative living space for seniors, much as some European countries have pioneered for humane care for elders.
That means higher training standards and salaries for those who provide care for those who are out of sight and mind for most Canadians in late life.
Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.