Neuro anatomical changes due to aging, cellular changes, auditory and visual changes

1. AGE RELATED CHANGES -
NERVOUS SYSTEM
Vaibhavi Rathod

2. Neuro anatomical changes with aging
• BRAIN WEIGHT
• GYRAL ATROPHY
• VENTRICULAR DILATION
• CNS METABOLISM & CEREBRAL BLOOD FLOW
• SUB CORTICAL NUCLEI
• MYELIN SHEATH
• CELLULAR CHANGES

3. 1.Decreased Brain weight

4. 2.Gyral Atrophy

5. 3.Ventricular
Dilation
• It accompanies aging and
decreased brain weight
• Impairments in naming and
abstract
• Language, cognition and
memory is spared

6. 4. Decrease in Cerebral blood flow and
decreased cerebral metabolism

7. 5.Sub Cortical Nuclei

8. 6.Cerebellum

9. 7.Neuronal degeneration

10. Cellular changes
• Integrated action is affected.
• Accumulation of lipofuscin intercellularly.
• Increasing phagocytic debris, dumping of mitochondria & deterioration of
neurotransmitter receptors.
• Synthesis of neurotransmitter is also reduced.

11. SOMATOSENSORY SYSTEM
An age related decline in some of the peripheral receptors as well as
afferent nerve fibers @ 5%-8% per decade after the age of 40
• Meissner’s corpuscles- decrease in number
• Pacinian corpuscles decrease in number
• Sensory and motor conduction velocities
decrease
• Touch – pressure perception approaches a
fourfold reduction in males
• Sensation in the lower extremity appears
more affected by aging than the upper
extremity
• age related increase in thresholds to
thermal pain
• age-related change in A delta mediated
pain(sharp, pricking)
• Joint position sense deteriorated with
advancing age
• Merkel cells unaltered
• Longer fibers and larger fibers are not most
affected
• Steregnosis and graphesthesia usually
remain intact
• no age related changes in pain threshold
• not in C-fiber mediated pain(dull,burning
or aching

12. Cognitive aging

13. Auditory Changes
• Prebycusis – age related changes in inner ear leading to decreased hearing
power
• 75% people above 60 yrs
• Decreased hair cells in cochlea of inner ear
• Loss of high frequency sounds
• Loss of sound localization
• Impairment of speech disturbances

14. Visual changes
• Loss of upper gaze and peripheral vision deficit
• Difficulty in depth perception, colour perception
• Difficulty to judge the distance
• Cannot reach the levels of dark adaptation that younger people can.
• Visual acuity affected due increased thickness of lens
• SENILE CATARACT, GLAUCOMA, MACULAR DEGENERATION, RETINOPATHY,
PRESBYOPIA, are common conditions leading to visual defects.

15. Common diseases :

16. In experimental settings the age related
changes in the brain are manifested as:
• Decrease in the ability to register, retain and recall recent experiences.
• Slower rate of learning new material
• Slower motor performance on task that require speed
• Increased reaction time
• Decreased NCV
• To initiate physiological response they require higher level of intensity and
longer duration.