Memory and Aging PowerPoint Presentation

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Memory and Aging

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Memory as We Age An irony – comparing our own current memory with our past memory requires memory. People are less able to accurately report memory lapses as they age. Sunderland et al. (1986) Complaints about memory in the elderly are more related to depression than actual memory performance. Rabbit and Abson (1990) Impaired memory is the earliest and best predictor of the onset of Alzheimer’s disease. 2

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Methods for Studying Aging A representative sample of people tested repeatedly over time Advantages: The effect of age can be determined on an individual basis, helping to pinpoint precursors of disease Disadvantages: Expensive Time consuming High dropout rate, often making the sample less representative Practice Effects: Participants get better at taking the same test with repeated testings Different groups of people are sampled across the age range, with each being tested once Advantages: No re-testing Quicker and less expensive Lower dropout rate Disadvantages Performance can’t be related to earlier/future data Cohort Effect: People born at different times differ due to: Diet Education Number of siblings Social factors (war, economic depression) Longitudinal Studies Cross-Sectional Studies 0 yrs +10 yrs +20 yrs Test #1 Test #2 Test #3 20-year- olds 0 yrs 20-year- olds 30-year- olds Test #1 40-year- olds 3

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Cohort Effects Flynn Effect: IQ has been rising across generations (Raven’s matrices) People have become taller and more educated, while family size has shrunk across generations From Rönnlund and Nilsson (2008). Copyright © Elsevier. Reproduced with permission. From Rönnlund and Nilsson (2008). Copyright © Elsevier. Reproduced with permission. 4

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Methods for Studying Aging Cross-sectional and longitudinal studies lead to different results Cohort and practice effects can be quite influential A Comparison Memory Decline with Age Longitudinal Data Cross-Sectional Data Based on Rönnlund et al. (2005). 5

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A Hybrid Method Combine longitudinal and cross-sectional approaches Add a new cohort at each test point Comparison down the columns measures learning effects e.g. 30-year-old cohort Test #1 to 20-year-old cohort Test #2 So both are then 30 years old at that point Comparisons across a test point for each group measure cohort effects e.g. 20-year-old cohort Test #1 to 30-year-old cohort’s Test #1 0 yrs +10 yrs +20 yrs Test #1 Test #2 Test #3 20-year- olds Test #2 Test #3 Test #1 Test #2 Test #3 Test #1 Test #2 Test #3 30-year- olds 40-year- olds 6

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Working Memory (WM) and Aging WM span progressively declines with age But it is a very small decline Effects are larger when tasks involve speed of processing or episodic, long-term memory May et al. (1999) The WM decline may be due to a build up of proactive interference that older adults are less able to inhibit 7

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Working Memory and Aging Hasher and Zacks’ (1988) Inhibition Deficit Hypothesis of Aging: A major cognitive effect of aging is the reduced capacity to inhibit irrelevant stimuli Molander and Bäckman (1989): Participants: Older and younger mini-golf players, matched in skill Task: Make golf shots Results: Concentration (measured by heart-rate deceleration) increased in the younger under competition conditions and performance was maintained, in contrast to a decline in performance in the elderly.  However, there were large individual differences. In another study, Bäckman and Molander (1986) showed that competition decreased the accurate recall of specific shots, and increased irrelevant recall in the older golfers, but did not influence recall in the young. Conclusion: Older adults are less able to shut out potential distracters. Inhibiting Interference 8

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Working Memory and Aging Charness (1985): Younger chess players scan more possible moves. Older chess players scan fewer moves but in greater depth. May reflect increased difficulty keeping track of multiple sources of information. Divided Attention in Aging: Dual-task performance is worse in advanced age than on the two separate tasks. This probably reflects general difficulty handling heavy cognitive loads, however. When tasks are made easier, dual-task performance is not affected by age. Concentration and Attention 9

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Aging and Long-Term Memory Episodic memory declines steadily through the adult years, across the board: Recall and recollection tests Verbal and visual materials Rivermead Behavioural Memory Test (everyday memory situations) Doors and People Test (people’s names, locations) Memory for card hands Memorizing passages Memory for conversations The magnitude of the decline depends on the nature of the task and the method of testing (recall vs recognition). Episodic Memory 10

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Declines in Episodic Memory The overall decline in episodic memory is modulated by: Processing capacity of the learner Elderly take longer to perceive and process materials Elderly are less likely to develop and use complex learning strategies Level of environmental support provided during retrieval Age effects are largest in tests lacking external cues (e.g. free recall) Modulating Factors (Craik, 2005) 11

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Declines in Episodic Memory Naveh-Benjamin (2000) Task: A recognition test for word pairs that were either semantically related or not Results: The older group had difficulty for unrelated items, but not for related Initial Conclusion: Elderly are less able to form new associative links Follow-up (Naveh-Benjamin et al., 2003): Gave younger group a concurrent task, which resulted in impairment for both related and unrelated items—this didn’t match the elderly group’s results – so it isn’t that the elderly are just slower processing information. Final Conclusion: Associative Deficit Hypothesis: The differences between young and old are attributable to basic learning capacity, rather than to attentional or strategic differences related to processing speed. Limited Attention or Capacity? 12

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Declines in Episodic Memory An age-related difficulty in binding together unrelated things Simply recognizing old faces or names is unaffected by age However, a concurrent task does reduce performance Recalling which name went with a face, is diminished in the elderly, as this requires binding This decline is even more pronounced than in the divided-attention condition Self-Performed Task Effect: Age effects are minimized by asking elderly to perform an action associated with a to-be-remembered item This deepens encoding, providing auditory, visual, manual, and self-related codes for the memory Associative Deficit Hypothesis From Naveh-Benjamin et al. (2004b). Copyright © American Psychological Association. Reprinted with permission. 13 “Break the match-stick. Shake the pen”

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Declines in Episodic Memory Age effects are clearest in recall tests, which lack external cues, while recognition tends to be relatively preserved in the elderly. This difference may reflect a combination of: Fewer retrieval cues in the recall task A greater involvement of association in free recall Whether recognition is impaired or not depends on the nature of the task: If familiarity (“knowing”) is sufficient—no deficit If recollection (“remembering”) is necessary—some impairment Level of Environmental Support at Retrieval 14

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Declines in Episodic Memory Recollection based Involves remembering the event in its context Declines substantially with age Does not represent a difference in confidence between young and old Consistent with the associative deficit hypothesis of aging Familiarity based Able to recognize an item as familiar, without being able to recall the context Relatively spared in the elderly Remembering Knowing Recognition: Remembering and Knowing 15

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Declines in Episodic Memory Prospective Memory: Remembering to carry out an intended action in the future without explicit reminders Test: Participants perform an ongoing task and respond either After a specified time After a cue occurs Results: An age-related decrement for both time-based and event-based tasks Prospective memory requires: Encoding the action to be performed Encoding the time when it should be performed Maintaining the information over a delay More difficult in real-life situations with divided attention Through rehearsal and/or periodic retrieval from LTM An external retrieval cue helps Actually performing the task when appropriate Prospective Memory in the Laboratory 16

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Declines in Episodic Memory Unlike laboratory situations, in real-life prospective memory scenarios the elderly often perform better than younger adults. Example Tasks: Ask participants to make a telephone call or send a postcard at a specified time. Rationale: Older people are more aware of their memory limitations and compensate with various strategies, such as: Diaries Reminders Older people live more ordered and structured lives, making it easier to form plans. Older people may have been more motivated to perform well on a memory task; younger people can explain memory slips by “being too busy”. Prospective Memory in Real Life 17

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Semantic Memory and Aging Semantic memory does not decline with age It actually expands with age in some areas: Vocabulary Historical facts Speed of access (a more sensitive measure) does decline, however. Naturalistic, longitudinal diary study (Kemper, 1990) revealed: Older adults tend to use sentences that demand less working memory. But they also write “better” and “more interesting” sentences. Baddeley et al.’s (1992) Speed and Capacity of Language Processing (SCOLP) Test: Spot-the-word vocabulary test: Participants pick the real word from the pseudo-word Highly resistant to age and disease Semantic processing test: Participants verify sentences as quickly as possible High accuracy rates Reaction times are very sensitive to age and other factors 18

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Implicit Learning and Memory Results are mixed, due to the wide range of implicit processes Moderately impaired with advanced age: Priming tasks involving response production (e.g. stem completion) Small/no impairment in the elderly: Identification tasks (e.g. lexical decision/word fragment) Stronger implicit effects in the elderly False Fame Effect: Participants first see unfamiliar names Then are asked to mark names that are famous Previously processed, unfamiliar names are judged as more famous Especially true for elderly participants Due to impaired recollection, forcing them to rely on familiarity The elderly may be more susceptible to false information and leading questions 19

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Implicit Learning and Memory Motor performance declines with age Speed of perception and movement decline Leads to slower learning rate on time-based tasks The rate of motor learning need not decline with age, however Young and old adults show comparable rates when learning: A sequence of motor movements New stimulus–response mappings To make serial responses to a number of stimuli under self-paced conditions To navigate a computer maze Motor Skills 20

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Implicit Learning and Memory Generally: When the response is obvious and performance is measured in terms of speed improvements The elderly perform well When the response is non-obvious, novel associations must be learned Older adults are impaired This is often the case for learning about new technologies Wilson, Cockburn, and Baddeley (1989) Task: Patients learn a simple process of entering the time/date into a handheld computer Results: Rate of learning was extremely sensitive to episodic memory deficits 21

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Resisting Age Effects Factors tending to correlate with resistance to memory impairment: Good physical health Appropriate diet Regular exercise Continued mental activity But rates of decline don’t differ across professors/blue-collar workers (Christensen et al., 1997) Meaningful material may allow the active learner to compensate for declining episodic memory (Shimamura et al., 1995) Explicit memory training (e.g. mnemonics) can help But young participants gain substantially more from training than the elderly An enriched environment (at least it works for rats …) Better to be safe than sorry: Follow the tips, even though evidence is still lacking in some respects 22

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Resisting Age Effects Ball et al. (2002) Participants: 2,832 older adults, divided into four groups 6-week Training Program: Group 1: Strategy training; practice on words and shopping lists Group 2: Practice on verbal reasoning tasks Group 3: Speed training on visual search and divided attention tasks Group 4: Controls (no training) Final testing all the task types and on everyday tasks Results: Groups 1 to 3 improved on the skills trained Despite being tested on novel materials No change occurred for untrained skills, however Improvements did not generalize to everyday tasks either Conclusion: Only specific skills can be trained; no generalization It’s possible that training had some protective effects Memory Training Programs—Worth It? 23

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Theories of Aging Many of the cognitive effects of aging are caused by reduced processing speed Based on extensive correlational data Digit Symbol Substitution Test (DSST) is a good predictor of age deficits The rest of the decline could be caused by a more general decline in cognitive functioning (Salthouse & Becker, 1998) Problems with the theory: Measures that correlate with age deficits aren’t pure speed tests DSST also involves strategy and working memory Many other physical and cognitive capacities that decline with age could have a causal effect Speed measures don’t always explain the most variance Grip strength is an even better predictor! Baltes and Lindenberger (1997) Speed Theory -- Salthouse (1996) 24

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Theories of Aging Reduced processing resources Dividing young participants’ attention can mimic performance of older adults However, this isn’t always true e.g. Naveh-Benjamin et al. (2003; 2004) Episodic deficits are more like amnesia than an attentional limitation Conclusion: Probably one of many factors Reduced ability to inhibit irrelevant information (Hasher, Zacks, & May, 1999) Problems: Why would this influence free recall? Why is performance on the Peterson task not influenced by age? After all, forgetting on this task is assumed to be caused by built up proactive interference Reduced WM Capacity – Inhibition Theory 25

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Theories of Aging The frontal lobes atrophy with advanced age Tasks thought to be supported by the frontal lobe also tend to decline with age These tasks typically rely on the executive component of working memory and/or inhibition However, the correlation between frontal lobe atrophy and age-related cognitive decline is weak and the theory is not well-specified currently Frontal Lobe Deficits 26

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The Shrinking Brain The latency of Evoked Response Potentials (ERP) increases with age The P300 increases at an average of 2 ms/year The rate of slowing becomes more dramatic in dementia 27

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The Aging Brain Broader activations in the elderly: WM and visual attention yield bilateral activation in the elderly (Cabeza et al., 2004) It is strongly lateralized in young participants Autobiographical memory activation in the hippocampus is bilateral in the elderly (Maguire & Frith, 2003) It is left lateralized in young participants Use of other brain structures is thought to compensate for overload of one brain component Reduced activations in the elderly: Elderly don’t show occipito-temporal activation that younger participants do in a complex visual memory task (Iidaka et al., 2001) Suggests the elderly aren’t using visual imagery Elderly benefited less from a visual mnemonic strategy With complex tasks, the elderly are no longer able to compensate and so rely on simpler strategies Neuroimaging Studies 28

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The Aging Brain Dopamine Related to numerous cognitive functions Agonists (e.g. bromocriptine) improve spatial working memory Antagonists (e.g. haloperidol) diminishes spatial working memory Levels correlate with episodic memory performance (Bäckman et al., 2000) R2 = 38% on word recognition R2 = 48% on face recognition Decreases 5–10% per decade of life According to both post-mortem and PET studies Depletion is associated with cognitive deficits in Parkinson’s and Huntington’s diseases Covarying out dopamine level nearly eliminates the effect of age on memory performance (Erixon-Lindroth et al., 2005) Neurotransmitters 29

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Normal Changes with Aging Normal changes with age: Slower thinking. Difficulty paying attention. Need more cues - like words, pictures, smell, etc. - to recall information. Using fewer memorization skills like visualization and organization. Associations are more difficult. Decline in vision and hearing. Common causes: Health related: High blood pressure Prescription drugs Bad nutrition Low Blood Sugar or diabetes Depression Anxiety Taking multiple prescriptions Lifestyle – lack of sleep, lack of activity, stress http://www.alz.org/alzheimers_disease_10_signs_of_alzheimers.asp

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Alzheimer’s Disease (AD) Prevalence: Accounts for over 50% of senile dementia cases Occurs to 10% of the population over age 65 The rate of occurrence increases with age Diagnosis: Requires memory impairment plus two other deficits Language, action control, perception, or executive function Difficult to diagnose early Ultimate diagnosis typically requires post-mortem examination finding dense Amyloid plaques Neurofibrillary tangles Warning signs (Petersen et al., 2001): Memory loss affecting job skills Difficulty performing familiar tasks Language problems Disorientation in time and place Poor/decreased judgment Problems with abstract thinking Misplacing things Changes in mood/behavior Changes in personality Loss of initiative Primary feature: Defective episodic memory 31

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Alzheimer’s Disease (AD) Disease Progression 32

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Alzheimer’s Disease (AD) Garrard et al. (2005) studied the progression of AD in Murdoch’s writings. Linguistic problems increased as the disease progressed Difficultly coming up with specific words Spelling deteriorated Sentences became shorter and used fewer low-frequency words This was probably a compensatory strategy Semantic difficulties Major problems in defining words appropriately Naming pictures became difficult Difficulty generating items from a semantic category A Case Study: Novelist and Philosopher Iris Murdoch 33

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Alzheimer’s Disease (AD) Deficits in/for: Recall Recognition Verbal materials Visual materials Everyday memory Recency is relatively preserved (like amnesic syndrome) At late stages, recency also tends to decline Performance on earlier items is grossly impaired Episodic Impairments Data from Greene et al. (1996). 34

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Alzheimer’s Disease (AD) Although AD patients have great difficulty acquiring new information, forgetting rates match those of normal elderly Kopelman (1985): Task: Matched picture recognition performance to normals’ (at a 5-minute delay) by increasing exposure time Re-tested picture recognition after 24 hours Results: Equivalent performance for AD patients and control elderly individuals Forgetting 35

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Alzheimer’s Disease (AD) Hodges, Patterson, and Tyler (1994) found that the degree of temporal lobe atrophy predicts deficits in semantic memory, as measured by a battery testing: Picture (objects or animals) naming Picture–name matching Describing characteristics of named/pictured objects Verifying sentences about objects The semantic deficits in AD are not as severe as they are for semantic dementia, in which: Episodic memory is relatively spared Atrophy primarily occurs in the left temporal lobe Damage in AD tends to be more medial Semantic Difficulties 36

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Alzheimer’s Disease (AD) Implicit Memory 37

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Alzheimer’s Disease (AD) Working memory is relatively less impaired than episodic memory; however, there are modest deficits in: Digit span Corsi block tapping (visuo-spatial memory) AD patients can maintain small amounts of material over unfilled delays, so long as they can use the phonological loop to rehearse Articulatory suppression causes rapid forgetting Normal elderly individuals are only affected by intellectually demanding filler tasks (e.g. counting backward by threes) The capacity for sustained attention is not significantly compromised Working Memory 38

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Alzheimer’s Disease (AD) Baddeley et al. (1986) Task: Matched digit load to normal performance Also matched secondary, nonverbal rotary pursuit task Had to perform digit span task either: Alone Simultaneously with the tracking task Results: Young and normal elderly: A slight performance decrease in dual-task condition AD patients: Showed a drastic decrease in the dual-task condition Deficits increase as disease progresses (Baddeley et al., 2001) All three groups behave similarly: In the single-task condition, regardless of difficulty level Working Memory 39

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Alzheimer’s Disease (AD) Donepezil, Rivastigmine, and Galantamine Inhibit cholinesterase Prevents the breakdown of acetylcholine A neurotransmitter that normally is depleted in AD In the disease’s early stages: Rely on preserved procedural and implicit memory to teach skills Errorless learning Fading cues Remember: “JOHNNY” Fill in “JOH_ _ Y” Fill in “J_H_ _ Y” Fill in “J_ _ _ _Y” Use simple memory aids like Message boards Calendars Modify the environment to make it clear where things should go Pharmacological Behavioral Treatment 40

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Alzheimer’s Disease (AD) Spector et al. (2000) Improved performance on specific areas trained Does not generalize to everyday memory performance Reduced depression Reality Orientation Training (ROT) Helps the patient orient in time and place Reminiscence Therapy Helps patients maintain a sense of personal identity Incorporates photographs and other reminders of their past life Can have them construct a personal life-story book Can be done in groups Facilitates patient–therapist interactions Training Programs 41