Neurological changes with aging

selective

"Cocktail Party"

Cognitive system changes

- Behavioral measures of intellectual function show little or no decline except in perceptual-motor tasks, timed tasks, and short-term memory tasks.

Changes in nerf cell morphology

- Decrease in *size of cell body, loss of dendritic density*, and decrease in number of dendritic spines on cortical pyramidal cells and motor neuron. - Overall *decrease in myelin*, accounting for much of the loss in brain volume with aging (rather than neuronal loss) - 2.5% loss of Purkinje cells per decade - Result in *slowing of movement and poor adaptability of movement responses*

Metabolic changes

- Decrease in cerebral blood flow with increase in cerebrovascular resistance. - Decrease cerebral oxygen consumption with age. - Rapid decline in cerebral blood flow & metabolism has been proposed from first to third decade of life. - Age-related declines in blood flow, oxygen need and metabolism are not profound enough to account for the degree of cerebral atrophy that accompanies aging.

Anatomical changes in the aging nervous system

- Decrease in size of brain - Weight decreases 5% by age 70, 20% by age 90. - Neuronal loss - Cortical neuronal loss is not present in normal aging - Present with dementia, neuro pathologies

Cognitive system changes: implications for PT

- Decrease rate of presentation or instruction of motor skills. - Allow for increased processing time. - Repeat often to compensate for memory deficits. - Facilitate learning by providing patients with organized strategies and/or memory aids. - Make learning meaningful. - Evaluate attitudes and biases regarding cognitive ability and learning potential in elderly.

Senile plaques

- Discrete structures located outside of the neuron. - Composed of degenerating small axons, dendrites, astrocytes and amyloid. - Begin to occur in fifth decade. - Exercise is a good prevention

Biochemical changes: neurotransmitters

- Evidence suggests that age-related changes do occur in each of the major neurotransmitters but the precise mechanism that produces a change is not known. - Loss of function can be related to - Synergistic effect of multiple neurotransmitters - Age-related lack of balance among neurotransmitters

Aging Cholingeric system: basal forebrain complex

- First cells to die in Alzheimer's - Produces Acetylcholine - Seem to regulated general brain excitability/arousal/ sleep/wake cycles (Thalamus) - May play a role in memory formation and learning (Hippocampus)

Explicit memory: age-related differences

- Free-recall tasks - Recall highly specific facts - Details of when & when

Outcome due to changes in motor behavior: vestibular system

- Function of vestibular system is to produce awareness of head position and to to control postural and ocular stability. - Presbyastasis - Age-related disequilibrium in the absence of pathology. - Vertigo, nystagmus, and postural imbalance may be symptoms of age-related decline if underlying vestibular pathology is ruled out

Changes in neurological function in healthy older adults

- Gradual slowing of ability to learn new information. - Gradual decline in some motor behaviors. - Muscle atrophy. - Decrease in number of functional motor units. - Increase in motor unit amplitude. - Decrease in motor nerve conduction velocities. - Decrease in proportion of fast-twitch muscle fibers.

Autonomic nerveuse system changes with aging

- Impaired ability to maintain internal homeostasis caused by problem with both neural and endocrine control mechanisms. - Basal sympathetic activity increases in old age. - Parasympathetic activity decreases in old age.

Senescence: progressive deterioration during the adult period of life

- Increase in vulnerability to challenges - Decrease in ability to survive

Neurological Pathologies

- Increased susceptibility and incidence of certain neurologic diseases as one ages - Stroke - Dementia - Alzheimer's disease - Certain vestibular disorders - Benign paroxysmal positional vertigo (BPPV)

Age-ralted decline in attention

- Intact - Selective - Focused - Divided - Decline - Selective - Divided - task complexity - simple vs more complex task - practice - experiences - x-ray technicians - task-specific practice

Secondary aging

- Interaction between primary aging and environmental influences and disease - Free radicals in mitochondria or as a result of environmental toxins promote aging

Noradrenergic system

- Involved in regulation of: attention, arousal, sleep/wake cycles, learning/memory, anxiety, pain, mood, brain metabolism - Part of ascending reticular activating system → arouse/awaken forebrain - Neurons of locus coerulus best activated by: new, unexpected, non-painful sensory stimuli from environment

Outcome due to changes in motor behaviors

- Maximal speed of movement is decreased. - Balance impairment - Increased postural sway. - Decrease in limits of stability. - Increase in threshold for vibration sensation and decreased proprioception. - Decreased ability to use peripheral vision.

sustained

- Military officer monitoring radar for enemy - Actively processing incoming information over given amount of time - Often measured in vigilance tasks -Classic test: "The Clock Test" - Performance significantly drops after approximately 30 minutes

Sustained attention: age-ranted differences

- Mixed evidence - may involve more than sustained attention alone (fatigue?) - Exposure time - if too short, older adults may miss target - Level of distinction - older adults may not observe difference if too subtle - Working memory load

Autonomic nerveuse system changes with aging: impact on physical therapy

- Monitor vital signs. - Teach patient to monitor own vital signs. - Know your numbers, Blood Pressure, Heart Rate - Avoid quick changes in body position. - Adjust rate and intensity of exercise. - Use perceived exertion scales - Stress can threaten internal homeostasis.

Cerebrovascular disease: ischemic vs hemorrhagic strokes

- More than half a million Americans have strokes each year, most are elderly, same risk factors as heart disease - Severity of stroke depends on area of brain affected and total amount of brain affected - Paralysis, speech disorders, confusion, balance problems, memory impairment and sensory impairment are common results - Diagnosis and treatment need to be swift to reduce impairment and risk of death

Serotoneric system

- Neurons most active during wakefulness/activity; least active during sleep - Part of ascending reticular activating system → arouse/awaken forebrain - Involved in control of mood & emotional behavior - Involved in perception of pain

Divided attention: age-related differences

- No age differences on simple tasks - Perceptual identification task - Simple reaction time task - Older adults perform worse than younger adults on more complex tasks - Task involving response to 2 distinct items presented simultaneously - little to no practice - Increased practice may reduce age-related differences

Focused attention: age-related differences

- No age-related differences in ignoring of distractors - Older adults able to find target as well as younger - No difference noted between groups

Neurofibrillary tangles - abnormal neurofibers

- Occur in hippocampal formation and certain brain stem nuclei in healthy aging brain. - Often displaces the nucleus, distorting the cell body - Greater incidence with age and with dementia.

Gains in cognition with age

- Postformal operations: problem-solving - Wisdom

Types of memory

- Procedural memory: Implicit memory - Perceptual representational system (PRS): Implicit and/or explicit - Sensory memory: Implicit and/or explicit - Episodic memory: Explicit memory - Semantic memory: Explicit memory

Varieties of attention

- Selective - focused - sustained - divided

Anatomical changes in the aging nervous system: neuronal loss

- Selective to certain subcortical areas. - thalamus, - basal ganglia, - locus coerelus, - hippocampus - basal forebrain

Types of memory

- Short-term memory: working (primary) - Long-term memory: permanent (secondary)

Keys to longevity

- Sleep: -Decrease inflammation/ better immune response - Diet: -Eat plants; fiber; protein -Minimize sugar - Exercise: -strength, stamina, aerobic capacity, mental acuity, reduction of disease risk, bone density, flexibility, balance, - Mental Health: -physical and mental health intertwined through personality, mood, stress & coping - Social and Environmental Factors: - sun exposure, noise, pollution, crime, stimulating environment, personal control, education, relationships

Dopaminergic network

- Substantia nigra - Facilitates initiation of voluntary movements/motor responses in response to the environment - *Area of the brain affected in Parkinson's Disease*

focused

- Watching movie in crowded theater - Knowing where a target will appear while distractors as also present - Involves concentration - Interest in target, motivation and fatigue are factors in ability to focus attention

divided

- Watching television while reading magazine - Simultaneously performing more than 1 task - Difficult to differentiate divided attention and task switching, usually considered one process - Task switching: rapidly switching between 2 or more tasks - Cognitive TUG?

Explicit memory: less impaired, sometimes superior to younger adults

- Word priming - Recognition memory - Knowledge of word meanings

selective attention: age-related differences

- Younger adults were faster than older adults on conjunction search task - Results suggest age-related differences in selective attention may be reduced in high experienced tasks - Older adults benefit more than younger adults from cuing in search task - May turn task from selective to focused attention

Primary (short-term) memory

- decline - may be able to train

Fundamental characteristics of aging

- intrinsically - universality - progressively - irreversibility - genetrically programed

Perceptual representational system

- not a lot of research but some assumptions - - should also be spared as early processes of implicit; but - others fear that sensory component is affected

Normal aging

-vSenescence in the absence of disease Natural death without disease - Very rare - Bone Loss

Pathological (disease)

Decline in function that occurs as a result of disease/pathology.

Functional (disuse)

Decline in physical function associated with the reduced physical activity.

Progressivity

Gradual increase in magnitude

Intrinsically

Inherent characteristic of the organism

Cellular senescence

Loss of proliferative ability of cell

Universality

Occurs in all member of a species

Primary aging

Universal change associated with age and not caused by disease and/or environmental influence

Cognitive system changes: crystallized intelligence

acquired through education and acculturation, remains stable through age 70.

biological aging

age-associated changes that involve the physical structures and functioning of the body and that affect a person's ability to function or survive.

Cognitive system changes: Fluid intelligence

capacity to use unique kinds of thinking to solve unfamiliar problems - believed to decrease with age.

Episodic memory

declines but can be reduced with cues

Semantic memory

declines very little

Procedural memory

well protected from aging & brain damage