9. Ageing Brain Flashcards
Vision changes
Corneal flattening Cataracts Decreased retinal efficiency Decreased lens elasticity- presbyopia Macular degeneration Glaucoma
Hearing changes
Decreased electricity of the eardrum
Reduced hearing of high frequencies due to less vibrations
50% over 75s have hearing loss, 8% wear AIDS
Taste
Less taste buds
Dampened taste
Touch
Reduced touch acuity sir to reduced blood supply and nerve fibres
Neuropathy
Age related changed to CNS
Gross brain atrophy Increased ventricular size Increased Semite plaques and neurofibrillartory tangles Selective regional neuronal loss Demyelination Reduced neurotransmitters Reduced blood supply and metabolic rate
Genetic evidence for ageing
3 main lines of support
Perl et al 2002
Siblings of centenarians live longer and have reduced incidence of Alzheimer’s
Swan et al 1992
MZ twins have more similar patterns of cognitive decline than DZ twins
Genes located in fruit flies which are related to lifespan
Perl et al
2002
Siblings of centenarians also live longer and have reduced incidence of Alzheimer’s
Swan et al
1992
MZ twins have more similar patters of cognitive decline than DZ twins
Which abilities are affected in cognitive decline
Inductive reasoning
Verbal memory
Perceptual speed
Spatial orientation
Attention is also decreased- mainly ability to switch attention (WM)
Driving is therefore implicated
Which abilities are spared with ageing
Numeric ability remains fairly constant across lifespan
Increase in verbal ability with speed
Blumenfeld and raganath
2007
Brain areas associated with stages of memory
ENCODING- VLPFC (BA44), parahippocampus
STORAGE- sensory (visual and motor cortex), stm (prefrontal), LTM (cerebellum and hippocampus)
RETRIEVAL- cognitive process dependent on strength of encoding
Age associated memory impairment
Normal memory problems with ageing such as forgetting famous people and appointments. Doesn’t interfere with daily life too much
Linear decrease in STM with age from 35 years
Motor skills, priming and learning are relatively spared- cerebellum spared
Temporary memory loss due to depression, anxiety, medication, infection, pregnancy etc
Park and Reuter-Lorenz
2009
Brain areas affected by ageing
Caudate nucleus
PFC
Hippocampus
Adults can compensate by making new neuronal networks to distribute functions to other brain areas
Mild cognitive impairment
When forgetting affects ADL
Similar to initial stages of of dementia
WM and LTM are affected
Environmental factors
Toxins Medication Drugs and alcohol B12 deficiency Thyroid Depression
