What happens to the brain and mind as we get older?

Dr Catherine Loveday

“A youth who does not respect his elders will achieve nothing when he grows up”

Confucius

INTRODUCTION

Why study the ageing brain?

Increasing no. of people over the age of 65

Research helps us to learn more about the ageing brain so that we can enhance the quality of old age Office for National Statistics

Variations in the effects of ageing

Changes in normal ageing brain not uniform: certain subsets of cells & areas of the brain more prone to age-related damage

Time of onset, extent of physical alterations & effect on intellect differ dramatically from one person to another

Leland McPhie age 95

SENSORY CHANGES Vision:

Lens becomes less flexible & yellowing of lens Cataracts, glaucoma, macular degradation

Hearing Large percentage of people 70 & above, have some hearing loss,

usually at high frequencies Taste & smell

Three-quarters of people over 80 have major difficulties with smell Smell more affected than taste but both linked Taste buds & smell receptors continue to be replaced throughout life so

more resilient Consequences for mental functioning & can be misleading

BRAIN CHANGES - vascular

Changes to the cardiovascular system: Circulation less efficient

brain less well nourished and toxins less efficiently removed

Greater likelihood of strokes and blood clots

Better cardiovascular health leads to better brain health

BRAIN CHANGES – key anatomical changes Overall number of brain neurons

decrease but pattern is not uniform. Parts particularly affected include

limbic system (learning, memory and emotion),

frontal lobes (planning, strategy, working memory)

substantia nigra (movement, reward, learning)

locus coeruleus (stress, panic, REM sleep)

BRAIN CHANGES - Neuronal

Damage to internal architecture of neurons may occur, e.g. neurofibrillary tangles

Areas between neurons may also be affected, e.g. amyloid plaques

Tangles & plaques occur in all ageing brains but are a particular marker of Alzheimer’s disease

BUT, not all neuronal changes are destructive…

Neuronal plasticity

Coleman, Flood & Buell (1987) Net growth of dendrites in

regions of hippocampus & cortex - middle age & early old age

Regression again in late old age. Postulated that initial dendritic

growth represents an effort by viable neurons to cope with the loss of their age-associated neighbours

BRAIN CHANGES- molecular Characterised by increased

numbers of free radicals and oxidised proteins (N.B. Progeria)

Ironically, proteases (enzymes responsible for breaking down oxidised proteins) are themselves oxidised

Studies in rats have shown that maze learning is directly related to numbers of free radicals and oxidised proteins

COGNITIVE CHANGES

Behavioural & cognitive changes surprisingly few Coping strategies may be developed in mid old age -

strengths focused on & lost abilities compensated (probably less effective in v old age)

Few people decline on all mental abilities - by 60s, most people have declined on one or two abilities (typically those used least throughout their life)

Not all individuals decline; few do so at a steady pace – tends to be stair-step (typically related to life events)

So which cognitive functions are affected by age?

Usually some reduction in fluid intelligence (logical problem

solving) memory (especially recall,

source memory, prospective memory and working memory)

processing speed (affects ability to do complex tasks or those with timed element)

executive functions (e.g. planning, disinhibition)

Which cognitive functions are not affected by age?

Knowledge & wisdom continue to grow

Crystallised intelligence remains stable (ability to apply knowledge & skills)

Vocabulary continues to grow Some aspects of memory are

resilient, e.g recognition memory

Piano – DrumEgg – SeedPoem – StatueEnemy – Friend

How to age-protect your brain (1)A healthy body means a healthy brain:

Physical activity, e.g. walking, running (physical & psychological benefits)

Keeping healthy: low incidence of cardiovascular or other chronic diseases

Good sensory systems with aids where necessary

Good diet + antioxidants? Avoidance of ingestion of agents that

interfere with the nervous system (e.g. alcohol, tranquilizers)

How to age-protect your brain (2) Psychological wellbeing is

just as important (direct impact on physical health & cognitive functioning)

Favourable and stimulating environment

Optimism & flexibility Minimising major life

changes in late old age Sleep & relaxation

How to age-protect your brain (3)

Maximise brain power Mental activity: “Use it or lose it!” Use strategies:

Make important things habitual Use memory aids & mnemonics Maximise attention when it

matters Use all senses One thing at a time

Allow more time

How do we detect changes in pathology over and above cognitive changes associated with ageing? Look at overall profile & observe nature & rate of change Eg Alzheimer’s disease begins with noticeable decline in

remembering event-based information. Rate of decline & appearance of new cognitive symptoms can

help to distinguish between dementia & mild cognitive impairment: More memory loss; disorientation for time, place & person; silly

errors in action & speech; depression & anxiety; personality intact Frontal lobe dementia will present first with personality

changes and executive dysfunction Diagnosis very important & also important to identify reversible

dementias

Conclusions Ageing leads to a range of physiological changes

both in the brain and the senses This leads to noticeable decline in some cognitive

functions but growth or resilience in others Keeping physically & psychologically well will age-

protect the brain and using strategies to compensate will also help

Sometimes ageing leads to abnormal brain changes - accurate diagnosis is important