Chapter 28: The Effect of ageing on the Nervous System Flashcards
Definition of dementia?
Loss of cognitive ability associated with gradual death of brain cells.
What is Alzheimer’s disease
Degenerative disease of the nervous system that particularly affects the temporal and frontal lobes of the brain.
Risk increases with age
Peptide molecule Beta-amyloid are produced by normal cerebral cortex neurones throughout life
An abnormal form of B-amyloid is associated with formation of plaques.
Causes of Alzheimer’s disease
Exact cause is unknown.
Multifactorial disease
- Increasing age - risk doubles every 5 years over age of 65.
- Family history of condition means risk is higher
What is familial AD?
Some alleles are known to cause AD, so inheriting them leads to early onset of disease (30-40)
Autosomal dominant alleles. - caused by:
Mutations in one of 3 genes:
- Gene for amyloid precursor protein (APP)
- gene for presenilin 1 and 2
What is sporadic AD?
Majority of cases are this. Risk factors: - Stroke - Severe or repeated head injury - Low level of education and intellectual activity - Variants of apolipoprotein E gene.... UNFINISHED!!!
What is vascular dementia?
Risk factors
- High BP
- Smoking
- High blood cholesterol
Memory and cognitive impairment occur due to reduced blood flow to the brain.
Often occurs as result of mini-strokes
Other symptoms of AD aren’t present, eg, no plaques
3 Main stages of development of AD
Early stages (mild AD)
Mid-stage (moderate AD)
Late-stage (severe)
Information on the early stages of AD
Memory loss + other cognitive deficits compensated for by the person, so can still function independently.
Difficult to express themselves.
Early signs of mood changes, eg, increased anxiety, agitation, confusion.
Ability to make decisions is reduced, as poor judgement.
Information on the mid-stages of AD
Personality changes and physical problems as cognitive ability declines further.
They require more care and support for daily activities
Increased confusion and disorientation
Disturbed sleep + mood swings
Information on the late-stages of AD
Symptoms more severe - distressing for patient, family, carers.
urinary + bowel incontinence
Completely dependent on care for daily life.
Frequent confusion and disorientation
Dysphagia.
Lifestyle choices to reduce age-related memory?
Regular Exercise Social Interaction Eating plenty of fruits and vegetables and drinks such as green tea. Managing stress Getting sufficient sleep Not smoking.
How does regular exercise help to reduce age-related memory?
Boosts brain growth factors
encourages development of new brain cells
How does social interaction help to reduce age-related memory loss?
Helps brain function by involving activities that challenge the mind.
Helps reduce stress and depression
How does eating plenty of food and vegetables and drinks such as green tea?
Contain abundant antioxidant
Foods rich in omega-3 fats (such as salmon, tuna, walnuts, flaxseed) have been found to improve memory
How does managing stress help to reduce age-related memory loss?
Cortisol, the stress hormone, damages the brain over time and an lead to memory problems
How does getting sufficient sleep help to reduce age-related memory loss?
Sleep is necessary for memory consolidation, the process of forming and storing new memories.
Lack of sleep also reduces growth of new neurones in the hippocampus.
Can cause problems with memory, concentration and decision-making.
How does not smoking help to reduce age-related memory loss?
Increase the risk of vascular disorders
Can cause stroke
Leads to constriction of arteries that deliver oxygen to the brain.
Differences between normal age-related memory changes and symptoms that indicate dementia?
Normal
- Person can live independently and carry out normal activities, despite occasional memory lapse.
Dementia
Person has difficulty performing simple daily tasks (washing up, dressing appropriately)
Normal
Person can recall and describe incidents of their forgetfulness
Dementia
Person unable to remember or describe incidents of their memory loss
Normal
Person’s judgement and decision -making ability is unaffected.
Dementia
Person has trouble making choices and may show poor judgement
Normal
Person may pause to remember directions but doesn’t get lost in familiar locations
Dementia
Person gets lost or disorientated even in familiar locations.
Examples of normal memory lapses?
- Forgetting where regularly used items have been left, eg, glasses/keys
- Forgetting names of acquaintances or blocking one memory with a similar one, eg, calling grandson by son’s name.
- Occasionally forgetting an appointment
- Having trouble remembering what the person has just read.
- Becoming easily distracted
- Walking into a room and forgetting why they went there.
Main difference between age-related memory loss and dementia?
Age-related memory loss isn’t disabling.
When memory loss becomes severe - disrupts person’s work, hobbies, social activities, family relationships. - possible warning signs of Alzheimer’s disease.
Causes of hearing impairments
Sensitive hair cells in cochlea (inner ear) damaged and die
Neurones in auditory nerve become damaged and die.
Other causes of hearing loss?
Noise-induced hearing loss caused by long-term exposure to sounds that are too loud, or for too long - damage sensory hair cells - once hair cells are damaged they don’t grow back and ability to hear is diminished
High blood pressure or diabetes
medications that are toxic to sensory cells in ears, eg, some chemotherapy drugs.
Disorders that affect vision as we age?
Age-related macular degeneration (ARMD)
Cataracts
Glaucoma
What is ARMD?
Age related macular degeneration
Can result in loss of vision in centre of visual field ( the macula) due to damage to the retina.
Two types - Dry ARMD, wet ARMD
