Section 6 Flashcards
Define senescence.
The progressive deterioration of many bodily functions over time
How can senescence effect motor processes?
Sarcopenia - weakness
Controversy about whether slowing and tremor seen in some people with age are a forme fruste (unfinished form) of PD or truly “normal aging”
How can senescence effect sensory processes?
Decline in vision, hearing, decreased sensation
In real-world performance, sensory, motor, and cognitive changes interact
E.g., listening to speech in noise:
Bottom-up negative aging effects: Peripheral changes (e.g., presbycusis) + deficits in central auditory processing (e.g., decreased efficiency of temporal and spectral resolution) + cognitive changes (e.g., reduced processing speed, decreased working memory
capacity, inhibitory deficits)
Top-down positive aging effects: Knowledge of language and content, which can bypass perceptual deficits
Age-related visuospatial decline on tasks such as three-dimensional construction and drawing
Howcan senescence effect cognition processes?
Slower rate of thinking, impaired memory, diminished ability to learn new things (e.g., languages)
With increasing age, humans slow down psychologically as they do physically
- Slower at perceiving, processing, and reacting to information, particularly when the situation requires rapid processing of complex information
- Healthy, older adults are more variable than younger adults
Main theory of cognitive aging is that it represents reduced inhibition and slow speed, with contributions from perceptual deficits, domain-specific cognitive impairments (e.g., in declarative memory encoding), and reduced cognitive capacity
E.g., more errors reading in noise if words are visually similar than if words are visually different; benefit on cognitive tasks from improved signal:noise ratio
How can senescence impact learning and memory?
Aging affects learning/encoding and retrieval of information more than fund of knowledge
(memories)
Slowing in information processing speed may result in a slower learning rate and greater need for repetition of new information
Changes in executive/control aspects of learning may affect learning strategies and therefore depth and rate of encoding new information, transfer of learning to novel situations, and retrieval
of newly learned information
Not all types of learning and memories are equally vulnerable
○ episodic > WM > semantic/lexical memory > procedural memory
Many older persons experience cognitive decline, also known as MILD COGNITIVE IMPAIRMENT
○ Some debate about whether all MCI is a precursor to Alzheimer-type dementia
How does aging change the brain?
Older adults, compared to younger ones, show structural changes in terms of gray and white matter volume reduction or reduced brain connectivity
These age-related changes are often accompanied by performance decline in additional cognitive processes such as executive function (i.e., attentional control, inhibition, working memory, and task monitoring), and episodic memory
Older adults exhibit lower performance than younger ones in lexical retrieval tasks using explicit and effortful paradigms such as picture naming and word naming from definitions
When executive function effects are minimized using tasks that do not require explicit lexical access, such as priming paradigms with word stimuli, studies have often reported comparable
performance in older, and younger participants
What does selective attention require?
(a) restricting access of irrelevant information to attention and working memory (i.e., access control);
(b) deleting irrelevant information from attention and working memory (i.e., deletion control); and
(c) restraining strong but inappropriate responses (i.e., restraint control)
What does age-related reduction in inhibitory control lead to?
(a) reduced ability to ignore concurrent distraction,
(b) reduced ability to delete information that is no longer relevant to the current task, and
(c) reduced ability to restrain responding when a prepotent response is inappropriate
What aspects of language decline with age?
Confrontation naming (word-finding) and generative naming may decline but not so to the extent that it interferes with communication
Language comprehension may be affected if information is complex and presented rapidly
Main effects on language are secondary to slower processing and poorer attention
What are the functions of the brain stem?
Conduit for pathways
Corridor for all major sensory, motor, cerebellar and cranial nerve pathways
Location of cranial nerve nuclei
Location of other nuclei with unique functions
Nuclei critical for control of consciousness, cerebellar circuits, muscle tone, and cardiac, respiratory, and other essential functions
Small lesions can result in major deficits involving motor, sensory, and neuroregulatory (e.g.,consciousness) modalities
What is the role of the reticular formation?
Core of nuclei that runs through the brainstem
Continuous rostrally with the diencephalon and caudally with the spinal cord
Rostral RF functions with diencephalic structures to maintain alert conscious state of forebrain
Caudal RF works with variety of CN & SN nuclei to carry out reflex, motor, autonomic
functions
Describe Alzheimer’s dementia.
Amyloid (A) build up in plaques that can be both a product or a cause of neuronal death (extracellular)
Tau (T) causes neurofibrillary tangles within cells caused by abnormal phosphorylation. This interferes with axonal transport and typically develops first in the entorhinal cortex, hippocampus and basal forebrain.
Inflammation
Neurodegeneration (N) is nerve cell death which is caused by the plaques and tangles resulting in inflammation
Describe frontal temporal dementia?
Pickbodies in the cortex with later atrophy of frontal and temporal lobes.
Describe semantic dementia.
Bilateral pathology of temporal lobes (left>right), may also affect frontal lobe:
TDP-43
Describe vascular dementia.
Focal neurologic signs
Describe lewy body dementia.
Neuropathology is distributed in frontal lobe, temporal lobe, basal
ganglia
Protein deposits (Lewy Bodies) in cell bodies
What is spontaneous recovery?
Associated with aphasia
No definite predictions concerning its length or extent
Maximum improvement in first 3 months
Probably continues for at least 6 months
In global aphasia, probably starts later, lasts longer; likewise in severe TBI (not in hypoxic injury)
At this point, several aphasia studies have looked at spontaneous recovery in absence of treatment
All support statistically significant improvement in first weeks after stroke
What are some important factors to consider in acute care intervention?
Patient status depends on medical factors
For stroke, type of stroke and extent of brain damage
Hemorrhage patients (if they survive) begin spontaneous recovery later, improve more than patients with thromboembolic strokes. True of cortical and subcortical stroke
For other ABI, recovery depends on extent of axonal vs. neuronal damage
Symptoms may evolve rapidly
What structures, aetiologies, and syndromes are commonly involved in language, according to the localization framework?
Left hemisphere: stroke and aphasia
What structures, aetiologies, and syndromes are commonly involved in cognition, according to the localization framework?
Frontal lobe: TBI and CCD
Right hemisphere: right-hemisphere pathology and RHD
Mesial temporal lobes: neurodegeneration and dementia.
What are some issues with talking commonly seen in aphasia?
Can’t think of the words you want to say.
Say the wrong word. Sometimes, you may say something related, like “fish” instead of “chicken.” or you might say a word that does not make much sense, like “radio” for “ball.”
Switch sounds in words. For example, you might say “wish dasher” for “dishwasher.”
Use made-up words.
Have a hard time saying sentences. Single words may be easier
Put made-up words and real words together into sentences that do not make sense.
What are some issues with understanding commonly seen in aphasia?
Not understand what others say. This may happen more when they speak fast, such as on the news. You might have more trouble with longer sentences, too.
Find it hard to understand what others say when it is noisy or you are in a group.
Have trouble understanding jokes.
What are some issues commonly seen with reading and writing with aphasia?
Reading forms, books, and computer screens.
Spelling and putting words together to write sentences.
Using numbers or doing math. For example, it may be hard to tell time, count money, or add and subtract.
Define dementia.
A syndrome resulting from acquired brain disease. It is characterized by a progressive decline in memory and other cognitive domains that, when severe enough, interferes with daily living and independent functioning
