Neurocognitive and Language Function in Aging and Dementia VanessaTaler, Ph.D. University of Ottawa Élisabeth Bruyère Research Institute
Neurocognitive and Language Function in Aging and Dementia Vanessa Taler, Ph.D. University of Ottawa Élisabeth Bruyère Research Institute
The aging brain
• lower volumes of grey matter resulting from reduced synaptic densities • some regions are more affected than others • e.g., prefrontal cortex • medial temporal structures
images from http://www.cse.buffalo.edu/, http://www.mybrainnotes.com/
Changes in white matter
Effects of aging on cognitive function
• With normal aging, we see declines in: • processing speed • episodic memory • working memory • executive function
• these declines are associated with brain changes (e.g., prefrontal volume, white matter integrity)
Intelligence
• Fluid intelligence: ability to think and reason abstractly and solve problems • Correlated with volume of prefrontal cortex
� Crystallized intelligence: the ability to use skills, knowledge, and experience
� Preserved in normal aging
Language changes with age
• Language function remains largely intact • However, it can be afffected by other changes with age (e.g., in processing speed, working memory) • Discourse comprehension is affected by both processing deficits and increases in language experience related to age: • working memory (integration of concepts, maintenance of thematic information over multiple sentences). • topdown influences (real world knowledge)
Considerations
• Many common health problems can have a deleterious—and additive—effect on cognition • Medications can affect cognitive function • Sensory acuity (visual and hearing function) is an important predictor of cognitive performance • Cross-‐sectional vs. longitudinal studies give different results
What is dementia?
• Significant loss of intellectual abilities such as memory capacity, severe enough to interfere with social or occupational functioning. • Criteria for the diagnosis of dementia include: • impairment of attention, orientation, memory, judgment, language, motor and spatial skills, and function • by definition, dementia is not due to major depression or schizophrenia.
What causes dementia?
• Most common causes include: • Alzheimer’s disease (AD) – 64% of cases
• vascular dementia (VaD) – up to 20% of cases
• Lewy body dementia (LBD) – 5-‐15% of cases
• frontotemporal dementia (FTD) – 2-‐5% of cases
• atrophy • senile plaques: buildup of beta-‐amyloid may interfere with neuronal communication. • neurofibrillary tangles: threads of tau protein become twisted.
image from http://alzheimer.ca/
Memory in AD • Memory impairment + impairment in one other cognitive domain • Affects primarily declarative memory (not procedural) • Declarative memory = memory for what • semantic memory (world knowledge, knowledge about the meaning of things) • episodic memory (personal memories)
• Procedural memory = memory for how (e.g., how to ride a bike) • Often remote memories are better recalled
Other cognitive domains in AD
• Impairments are also seen in: • executive function • judgment, decision making • calculations • visuoperceptual function • language function
Other dementias
• Lewy body dementia: • both AD-‐like and Parkinsonian symptoms (rigidity; tremors; stooped posture; slow, shuffling movements.); visual hallucinations
• Vascular dementia: • often co-‐occurs with AD and manifests similarly • stroke is a common cause; symptoms vary depending on brain regions affected
• Frontotemporal dementia: • behavioural variant (frontal) • language variant (temporal)
Language deficits in AD
• Word-‐finding difficulty • Gradual loss of knowledge about word meaning • Deficits in standardized language tests: • Naming • Verbal fluency, especially semantic fluency
• Language production • semantically impoverished discourse that is lacking in coherence
Communication in dementia
• Communication is profoundly affected in dementia, and has a major impact on quality of life
• Declining communication function leads to: • increased stress
• loneliness, and social withdrawal
• earlier institutionalization
How do we improve communication?
• Learning about dementia, its progression, and how it affects individuals. • Believing that communication is possible. • Focusing on remaining abilities and skills. • Reassuring the individual with dementia and being positive. • Meeting people with dementia where they are and accepting their reality.
(Alzheimer Society of Canada)
Strategies for communication cont.
• Eliminate distractions (TV, radio, etc.)
• Use body language and non-‐verbal communication
• Letting the person see your face helps them understand you
• One thing at a time
• Don’t use elderspeak!
The effects of bilingualism
• The number of bilinguals in Canada is large and increasing • Bilingualism affects neuropsychological assessment, especially since most tasks are administered verbally. • Bilingual patients prefer care in the native language, and caregiving in the second language reduces apparent competence and quality of life.
• Bilingualism may delay the onset of dementia. • Why?...
What is “cognitive reserve”?
• Cognitive reserve (CR) is the brain's capacity to cope with cerebral damage to minimize clinical manifestations. • Researchers do not yet fully understand what CR is but some factors may include: • education • occupation • social interactions • physical activity
• “Use it or lose it” – bilingualism may be a form of “using it”
Looking after your brain
• Stay intellectually engaged • At best, mental activity seems to protect against age-‐related declines and progression to AD. • At worst, it increases an individual’s baseline level so that age-‐related declines begin to affect everyday functioning later in life. • Enriched environments stimulate neurogenesis in aged rats, indicating a possible mechanism for the benefits of cognitive stimulation.
Looking after your brain cont.
• Maintain cardiovascular physical activity
• Exercise appears to:
• aid executive function
• reduce declines in tissue density in frontal, parietal and temporal cortex
Looking after your brain cont.
• Minimize chronic stressors • Proneness to distress is associated with increased risk of AD and a faster rate of cognitive decline • Increased glucocorticoid levels, which accompany stress, might damage hippocampal neurons over the lifespan
Thanks to:
• Alzheimer Society of Canada
• Canadian Institutes of Health Research
• Élisabeth Bruyère Research Institute
• All the members of my lab!