dementia case study

DementiaA Family Tragedy

Mark Gronowski

Monday, 29 April, 13

What is Dementia?

• A brain disorder that produces wide spread deterioration of mental functions and social capabilities

• A chronic condition that is usually progressive, although the term can also be applied to static conditions

• A tragedy for the victim and for family and friends


Forms of Dementia• Alzheimer’s Disease (AD)

• Vascular Dementia (VaD)

• Frontotemporal Dementia (FTD)

• Pick’s Disease

• Dementia with Lewy Bodies

• Creutzfeldt-Jakob Disease (CJD)

• Huntington’s disease (HD)

• Parkinson’s disease (PD)

• Wernicke-Korsakoff Syndrome

• And more..


Types of Dementia• More then half of all dementias are Alzheimer’s

Disease (AD), followed by Vascular Dementia (VaD)

• AD and other forms of dementia are irreversible, however there are some that can be reversed with the appropriate treatment

• The assessment process, many of the symptoms and effects of the illness on the victim and family are similar whatever the type of dementia


Alzheimer’s Disease• AD is the 4th most common cause of death after heart disease,

cancer and stroke

• Gradual onset and continuous cognitive decline

• Late-onset AD occurs at 65 years of age and up (majority)

• Early-onset AD can occur between age 40 and 65 years

• There is no cure for AD, however there are several treatments to help slow down progress of AD

• Interventions

• Anti-depressants / Antipsychotics

• Nutrition, meaningful activities, and a familiar environment


Early stage deficits• Usually the first symptom to emerge in AD and many other

dementias is forgetfulness

• Increasing impairment of learning and short term memory

• Impoverished speech

• Shrinking vocabulary and decreased word fluency

• Patient is aware of these difficulties and may avoid new situations to minimize embarrassment or failure

• May become depressed as they realize what’s happening

• Difficulty with perception (agnosia) or executive movements (apraxia)


Middle stage deficits• Difficulties with executive functions

• Abstract thinking gradually becomes difficult

• Difficulty comprehending novel situations and subtle nuances of language and nonverbal expression

• Frequent incorrect word substitutions (paraphasia)

• Delusions and hallucinations

• Personality changes

• Rapid changes in emotion / agitation

• Impaired long-term memory


Late stage deficits• Profound anterograde and retrograde amnesia

• Poor judgement and impulse control

• Disinhibited behaviors are common

• Loss of insight (Anosagnosia)

• Alleviates depression

• Extreme apathy and exhaustion

• Loss of spontaneous speech / Mute

• “Vegetative state”

• Complete dependence on caregivers


Diagnosis• In general a longitudinal assessment demonstrating a

progression of cognitive deficits would be required to make a diagnosis

• Number of test batteries or Wechsler Scales can be given over time to assess progressive dementia

• Rating scales and questionnaires can also be given at regular intervals to assess daily functioning

• A history, physical examination, lab tests and brain imaging should be conducted

• Assess whether a specific organic factor is present that is etiologically related to the specific type of dementia

• Excludes other specific dementias


Assessment• MMSE (Mini Mental State Examination) is the most common measure

of global cognitive decline

• Shows any decline in cognitive functioning, particularly in memory function

• Single-photon emission CT (SPECT) measures regional cerebral blood flow and perfusion defects

• Good confirmation of AD diagnosis

• Can be used to distinguish AD from VaD

• Post-mortem confirmation

• Overdiagnosis and misdiagnosis

• Delayed diagnosis


Case Study• Sophie

• Journalist

• Prided herself on her excellent memory and often conducted entire interviews without taking notes

• Diagnosed with AD at age 51

• Genetic predisposition

• Not the first member of her family diagnosed with AD

• Her Mom was diagnosed with the disease at age 65 and had died at at the age of 70


Middle Stage Late StageEarly Stage

Initial Assessment


Sophie’s case: Early Stage

• Short term memory problems started at age 49

• Found difficulties with reading

• Aware of the history of AD in her family

• Decided to see a psychologist - But told that her low scores were probably attributed to fatigue and anxiety

• ‘Imagining her problems’


Sophie’s case: Initial Assessment

• Results of her initial assessment:

• Wechsler Adult Intelligence Scale (WAIS) & Wechsler Memory Scale (WMS)

• Scored in the average range

• Rey Complex Figure delayed recall

• Scored 2 SD’s below the average score for a woman of her age

• Showed mild symptoms of verbal and visuospatial memory impairment and word-finding problems



Initial Assessment

Followup Assessment & Diagnosis


Sophie’s case: Middle Stage

• Over the next 18 months it became apparent even to her family that something was wrong

• Sophie retired from her radio talk-back show

• She was frequently unable to find the words she wanted

• Repeated questions she had asked only minutes before and forgot the name of the person she was interviewing

• Referred to a geriatrician to be assessed


Sophie’s case: Medical Assessment

• MMSE (Mini Mental State Examination)

• Sophie’s score fell in the moderately impaired range

• Physical examination was normal

• Sophie, “could have passed for 40 rather than 50”, “her voice was strong and clear”

• No history of hypertension, strokes, heart problems, metabolic imbalances or endocrine disease that could account for her symptoms of memory impairment and speech difficulties

• No neurotoxic exposure or other physical effects from work

• No history of psychiatric disturbance

• No metabolic disorders


Sophie’s case: Brain• CT scan:

• No areas of infarction (stroke) or any mass lesions

• Lateral ventricles slightly larger then normal for her age

• Minor cortical atrophy

• Reversible causes of dementia were ruled out

• However, irreversible dementia was not yet certain, so further studies were conducted


Sophie’s case: Gradual Cognitive Decline

• Important dates and events were recalled and explored

• A gradual decline of memory, word-finding abilities and a problem finding her way around were all evident

• Onset consistent with a dementing process such as AD

• Not consistent with vascular dementia

• Tends to have a more distinct onset and a stepwise progression

• A more abrupt onset of memory and cognitive difficulties would increase likelihood of depression as a causative factor, which was not evident


Sophie’s case: Executive Function

• Wisconsin Card Sorting Task (WCST)

• Grasped the first category after 4 card sorts

• Preservation

• After 8 incorrect sorts, she sorted to the correct category but then immediately returned to the original category

• Became increasingly angry with each failure to sort correctly

• Difficulty making decisions involving abstract concepts

• Difficulty modifying performance in response to verbal feedback


Sophie’s case: Executive Function

• Interpreted as indicative of frontal-lobe dysfunction

• Consistent with the middle stages of AD

• Demonstrated insight into her difficulties, indicating that frontal-lobe dysfunction was not yet advanced

• These findings had implications for her care and treatment:

• Treatment with antidepressants or counselling would help alleviate the depression

• She still had the ability to think for herself and make decisions about her treatment and future


Sophie’s case: Premorbid IQ• National Adult Reading Test (NART)

• A word pronunciation test

• Good estimate of premorbid IQ for dementia

• Correlates highly with the WAIS IQ

• Since pronunciation of irregularly spelled English words do not deteriorate at the same rate as other cognitive abilities in dementia

• Sophie’s premorbid IQ estimated to be in the superior range


Sophie’s case: Longitudinal Assessment

• Initial assessment, 18 months earlier, made longitudinal assessments possible

• The second instance of the WAIS demonstrated Sophie’s scores now fell 1 or 2 SDs below average

• Visuospatial abilities (block design, object assembly and picture arrangement)

• Abstract concepts (similarities and questions asking for an explanation of proverbs)

• Slowed responses (digit symbol subtest)

• Word-finding problem (struggled to find the words to define a simple word that she was able to demonstrate by circumlocution)


Sophie’s case: Longitudinal Assessment

• Second instance of the Rey Complex figure

• Dramatic deterioration from initial assessment

• Showing further decline in visuospatial function


Sophie’s case: Memory

• Episodic memory

• Informally assessed by comparing events she recalled to those recalled by her husband

• Could spontaneously recall details of major events held in the past year (i.e. her 50th birthday)

• Unable to recall any details of a television series they watched over a recent 6-week period

• Vague feeling of familiarity but could not add any detail


Sophie’s case: Memory

• Showed significant decrease in memory test scores (WMS)

• Poor recall of logical memory passages

• Paired-associates memory subtest

• Recalled all obvious pairs (e.g. baby-cries), but none of the unusual pairs (e.g. school-grocery)

• Recall of Rey figure after 45min consisted of a rectangle and nothing else

• Recognition Memory Test

• Scored 2 SDs below average on word and face recognition


Sophie’s case: Language

• Aphasia Battery

• Good comprehension

• Difficulty repeating meaningless sentences (e.g. “The day, that the dream thought, jumped cheaply”)

• Descriptions of ‘actions’ in pictures was impoverished


Sophie’s case: Diagnosis

• Results support the evidence that her poor performance was not of pseudodementia (i.e. depression)

• Demonstrated a generalized cognitive decline

• In relation to estimated premorbid IQ, decline was even more significant

• A diagnosis of probable AD was made with the results of the neuropsychological assessment and medical investigations



Initial Assessment

Followup Assessment & Diagnosis

Management


Sophie’s case: Management• Lived at home for 4 years, and eventually placed in a hospice as the

dementia progressed

• Sophie’s depressed mood improved as her insight decreased, and within a year of diagnosis she no longer experienced periods of depression

• Made inappropriate/insensitive comments

• Forgot or confused her children’s names

• Became agitated for no apparent reason

• Cognitive function deteriorated rapidly once placed in the hospice, within 6 weeks she was mute and could recognize no one

• Death followed soon after


Sophie’s case: Conclusions

• Post-mortem it was confirmed that she had suffered from AD

• Sophie’s assessment and diagnosis were more straightforward than is often the case

• Primarily because of her own knowledge of the disease


Sophie’s case: Contributions

• Sophie’s case has shown us that:

• Longitudinal assessments are key to diagnosing AD, as they show any trend of cognitive decline

• Premorbid IQ is also an aspect that should not be overlooked

• Placement in an environment with no support leads to rapid decline in cognitive function

• A supportive family and familiar environment may be the best way to help slow progression of AD


Sophie’s case: Additional Tests• Natural Environment Testing

• Frequently exposing patient to “open experiences” of novel stimuli

• Nature and city walks, social experiences with new people..etc

• Assess changes in attention (Trail Making Test), language abilities (Aphasia Battery) and executive function (Tower of London)


D.H.’s Case Study• Patient D.H.

• Teacher, with 2 years of college education

• Medically and cognitively healthy

• Recruited as a control participant through the Alzheimer’s Disease Research Centre for a study of executive functions in older adults

• Annual neuropsychological assessments

• Followed for 6 years, beginning at age 81

• Diagnosed with probable AD in her 6th year of assessment

Jacobson et al. (2009)


D.H.’s case: Assessment• Premorbid IQ in the high average range

• Mattis Dementia Rating Scale

• Above average range

• MMSE

• Score remained within normal limits

• Performance on most individual tests in most domains (e.g., language, psychomotor..etc) were above typical cutoff levels for impairments relative to the normative group

• CVLT long-delay recall score

• No decline into an impaired range until her final assessment prior to her AD diagnosis


D.H.’s case: Diagnosis• 5th assessment

• Reported symptoms consisted with mild depression

• Diagnosed with pseudodementia

• Referred for neuroimaging studies

• 6th assessment (age 86)

• Complained of subjective changes in memory ability and some functional impairment in activities of daily living

• Assessment revealed moderate impairment on memory tests and in multiple cognitive domains

• Received a diagnosis of probable AD


D.H.’s case: Brain• MRI scan

• Following 5th assessment, one year prior to diagnosis of probable AD

• Asymmetric atrophy in medial temporal regions (particularly in left hemisphere)

• Generalized cortical atrophy in temporal lobe regions

• Enlarged ventricles


D.H.’s case: Pre-AD Analysis

• Annual assessments before diagnosis, during the asymptomatic preclinical stage of AD, have provided much data for pre-AD analysis

• Discrepancy scores used to identify subtle declines in cognitive skills relative to ones more resilient to dementia


D.H.’s case: Verbal vs Spatial tasks

COGNITIVE DISCREPANCY CASE STUDY 283

impairment until one year prior to her AD diagno-sis. Her cognitive-discrepancy scores steadilyincreased over time, yielding a 1 SD differencebetween verbal/visual recall in four of six assess-ments.

Cognitive discrepancies: Executive function and Memory tasks

We examined verbal fluency discrepancies using threeconditions of the D-KEFS Verbal Fluency test:

Letter Fluency (average of F, A, and S), CategoryFluency (animals and boy’s names) and Category-Switching (alternating fruit and furniture words); seeFigure 4. Her test scores demonstrated consistentlyabove-average and stable performance on letter flu-ency relative to a gradual decline on the two types ofcategory-fluency tasks. The cognitive-discrepancyscores between letter and category-switching fluencywas greater than 1 SD in all six assessments.

We used the D-KEFS Trail Making Test toexamine discrepancies between complex visuomotorsequencing/shifting ability, and a basic-skill task

TABLE 3 Verbal vs. spatial discrepancies: Mean (SE), frequency and range over six years

Mean (SE) z-score discrepancy

# Years with >1 SD z-score discrepancy

Minimum and maximum z-score discrepancy

Cognitive Discrepancy: Verbal vs. Spatial Task ComparisonsNaming (BNT) vs. Visuoconstruction (BD) 2.56 (.72) 5/6 0.85–5.26Auditory Attention (DS) vs. Visuospatial Attention (VS) 1.38 (.13) 5/6 1.0–1.66Verbal Recall (CVLT) vs. Visuospatial Recall (HVRT) 1.47 (.41) 4/6 0.31–3.04

Basic-level Task vs. Complex Skill Comparisons Letter (LF) vs. Category Fluency (CF) 1.89 (.31) 5/6 0.67–2.66Letter vs. Category-Shifting Fluency (CSF) 2.71 (.23) 6/6 1.99–3.66Motor Speed (MS) vs. Number/Letter Sequencing &

Shifting (SS)1.05 (.36) 3/6 0.25–2.66

Color Naming & Word Reading (CNWR) vs. Color/Word Inhibition only (CWIT)

0.73 (.33) 2/6 0–1.66

Color Naming & Word Reading (CNWR) vs. Inhibition & Shifting (CWITS)

2.39 (.60) 5/6 0–3.33

Vocabulary (VOC) vs. Verbal Learning Trials (CVLT1-5) 1.40 (.42) 3/6 0.05–2.90

Abbreviations: BNT, Boston Naming Test; BD, WAIS-R Block Design subtest; DS, WAIS-R Digit Span subtest; VS, Visual Scanningcondition D-KEFS Trail Making; CVLT, California Verbal Learning Test Delayed Recall; HVRT, Heaton Visual Reproduction Test–Russell version (Russell, 1975); LF / CF / CSF, D-KEFS Verbal Fluency: Letter / Category / Category Shifting; MS / SS, D-KEFSTrail Making Motor Speed / Sequencing and Shifting; CNWR, D-KEFS Color Word Interference Test combined Color and Wordreading; CWIT, D-KEFS Color Word Interference Test-Interference condition; CWITS / Interference Shifting condition; VOC,WAIS-R Vocabulary subtest; CVLT1-5, California Verbal Learning Test Learning Trials 1–5.

Figure 1. Visual Scanning versus Verbal Attention Span Discrepancies: D-KEFS Visual Scanning with Mildly Impaired Digit Span Scores.

VISUAL SCANNNG VERSUS VERBAL SPAN

–1.5

–1

–0.5

0

0.5

1

1.5

YEARS TO AD DX

Z-SC

ORE

D-KEFS Visual Scanning Digit Span Subtest

6 5 4 3 2 1

Downloaded By: [Canadian Research Knowledge Network] At: 01:05 25 February 2010


D.H.’s case: Verbal vs Spatial tasks284 JACOBSON ET AL.

requiring visuomotor speed (tracing a line between aseries of circles with no letters or numbers; seeFigure 5). While DH’s performance on thebasic-ability task remained stable (and withinnormal limits), her scores on the Number/LetterSwitching showed considerable variability,eventually declining into the impaired range. Hercognitive-discrepancy scores reflected a 1 SDdifference between complex and basic-skill tasks onthree of six assessments.

DH’s performance on four conditions of the D-KEFS Color/Word Interference Test (CWIT) isshown in Figure 6. A basic-skill composite measurewas computed as the average of the Color Naming(CN) and the Word Reading (WR) conditions. Thecomplex skills consisted of (a) interference-onlycondition (traditional Stroop test), and (b) theinterference/shifting condition (switching between

naming the dissonant ink-color and reading thedissonant word). Cognitive-discrepancy scoresbetween basic-skill and interference-only measureswere greater than 1 SD in two of six assessments.However, the cognitive discrepancy score usingthe more difficult interference/shifting paradigmresulted in a greater than 1 SD discrepancy relativeto the basic-skill measure (mean of CN & WR) infive of six assessments, largely the result of declin-ing scores on the two complex CWIT conditions.

We examined the participant’s discrepancybetween basic word knowledge (WAIS-R Vocabu-lary subtest) and complex verbal learning ability(CVLT learning trials; total for trials 1–5) (seeFigure 7). DH showed a significant cognitive dis-crepancy between her word knowledge and hertotal verbal learning ability on three of the sixassessments prior to her diagnosis change.

Figure 2. Visuoconstruction versus Verbal Naming Discrepancies: Stable Block Design Scores with Declining Boston Naming Scores.

VISUOCONSTRUCTION VERSUS VERBAL NAMING

–5

–4

–3

–2

–1

0

1

2

Years to AD Diagnosis

Z-SCORE

Block Design Test Boston Naming Test

6 5 4 3 2

Figure 3. Visual Recall versus Verbal Recall Discrepancies: Increasing Discrepancy between HVRT and CVLT Long-delay RecallScores.

VISUAL RECALL VERSUS VERBAL RECALL

–2–1.5

–1–0.5

00.5

11.5

22.5

Years to AD diagnosis

z-sc

ore

HVRT Delay Free Recall CVLT Long Delay free recall

6 5 4 3 2 1



D.H.’s case: Verbal vs Spatial tasks

284 JACOBSON ET AL.

requiring visuomotor speed (tracing a line between aseries of circles with no letters or numbers; seeFigure 5). While DH’s performance on thebasic-ability task remained stable (and withinnormal limits), her scores on the Number/LetterSwitching showed considerable variability,eventually declining into the impaired range. Hercognitive-discrepancy scores reflected a 1 SDdifference between complex and basic-skill tasks onthree of six assessments.

DH’s performance on four conditions of the D-KEFS Color/Word Interference Test (CWIT) isshown in Figure 6. A basic-skill composite measurewas computed as the average of the Color Naming(CN) and the Word Reading (WR) conditions. Thecomplex skills consisted of (a) interference-onlycondition (traditional Stroop test), and (b) theinterference/shifting condition (switching between

naming the dissonant ink-color and reading thedissonant word). Cognitive-discrepancy scoresbetween basic-skill and interference-only measureswere greater than 1 SD in two of six assessments.However, the cognitive discrepancy score usingthe more difficult interference/shifting paradigmresulted in a greater than 1 SD discrepancy relativeto the basic-skill measure (mean of CN & WR) infive of six assessments, largely the result of declin-ing scores on the two complex CWIT conditions.

We examined the participant’s discrepancybetween basic word knowledge (WAIS-R Vocabu-lary subtest) and complex verbal learning ability(CVLT learning trials; total for trials 1–5) (seeFigure 7). DH showed a significant cognitive dis-crepancy between her word knowledge and hertotal verbal learning ability on three of the sixassessments prior to her diagnosis change.

Figure 2. Visuoconstruction versus Verbal Naming Discrepancies: Stable Block Design Scores with Declining Boston Naming Scores.

VISUOCONSTRUCTION VERSUS VERBAL NAMING

–5

–4

–3

–2

–1

0

1

2


Z-SCORE

Block Design Test Boston Naming Test

6 5 4 3 2

Figure 3. Visual Recall versus Verbal Recall Discrepancies: Increasing Discrepancy between HVRT and CVLT Long-delay RecallScores.

VISUAL RECALL VERSUS VERBAL RECALL

–2–1.5

–1–0.5

00.5

11.5

22.5

Years to AD diagnosis

z-sc

ore

HVRT Delay Free Recall CVLT Long Delay free recall

6 5 4 3 2 1



D.H.’s case: Executive function and Memory tasksCOGNITIVE DISCREPANCY CASE STUDY 285

She exhibited a gradual decline in verbal learningability, relative to stable and average to above-average performance on the Vocabulary task.

Figure 8 summarizes the pattern of the two typesof cognitive-discrepancy scores across six assess-ments. We plotted the average of the combined cog-nitive discrepancy scores (z-score differences) foreach assessment for all verbal/spatial discrepancies(Figure 8a), and for all complex/basic-skill discrep-ancies (Figure 8b). We fitted two linear trend lines tothese data, which indicated positive slopes over timefor verbal/spatial discrepancies (y = .391) and com-plex/basic-skill discrepancies (y = .387), suggesting

an overall increase in cognitive-discrepancy scoresas D.H. approached an AD diagnosis.

Neuroimaging

The participant underwent structural magneticresonance imaging (MRI) following the fifth assess-ment, one year prior to a change in diagnosis toprobable AD. High-resolution anatomical imageswere acquired using a T1-weighted fast-spin echo(SPGR) at a 1.5-Tesla GE MRI scanner (TR = 24ms, TE = 5 ms, flip angle = 45 degrees, FOV = 24

Figure 4. Verbal Fluency Discrepancies: Stable Letter Fluency Relative to Declining Category and Category Switching Scores.

VERBAL FLUENCY DISCREPANCIES

–2

–1.5

–1

–0.5

0

0.5

1

1.5

2

2.5

3


Z-SC

ORE

DKEFS Letter Fluency DKEFS Category Fluency

DEKFS Category Switching

6 5 4 3 2 1

Figure 5. Trail Making Test Discrepancies: Stable Basic Motor, Sequencing Skills with Variable Performance and Deficits in ShiftingCondition.

TRAIL MAKING TEST DISCREPANCIES

–3

–2.5

–2

–1.5

–1

–0.5

0

0.5

1

1.5

2


Z-SC

ORE

DKEFS Trails Motor SpeedDKEFS Trails Average of Num & Letter SequencingDEKFS Trails Number/Letter Sequencing + Shifting

6 5 4 3 2 1




She exhibited a gradual decline in verbal learningability, relative to stable and average to above-average performance on the Vocabulary task.

Figure 8 summarizes the pattern of the two typesof cognitive-discrepancy scores across six assess-ments. We plotted the average of the combined cog-nitive discrepancy scores (z-score differences) foreach assessment for all verbal/spatial discrepancies(Figure 8a), and for all complex/basic-skill discrep-ancies (Figure 8b). We fitted two linear trend lines tothese data, which indicated positive slopes over timefor verbal/spatial discrepancies (y = .391) and com-plex/basic-skill discrepancies (y = .387), suggesting

an overall increase in cognitive-discrepancy scoresas D.H. approached an AD diagnosis.

Neuroimaging

The participant underwent structural magneticresonance imaging (MRI) following the fifth assess-ment, one year prior to a change in diagnosis toprobable AD. High-resolution anatomical imageswere acquired using a T1-weighted fast-spin echo(SPGR) at a 1.5-Tesla GE MRI scanner (TR = 24ms, TE = 5 ms, flip angle = 45 degrees, FOV = 24

Figure 4. Verbal Fluency Discrepancies: Stable Letter Fluency Relative to Declining Category and Category Switching Scores.

VERBAL FLUENCY DISCREPANCIES

–2

–1.5

–1

–0.5

0

0.5

1

1.5

2

2.5

3


Z-SC

ORE

DKEFS Letter Fluency DKEFS Category Fluency

DEKFS Category Switching

6 5 4 3 2 1

Figure 5. Trail Making Test Discrepancies: Stable Basic Motor, Sequencing Skills with Variable Performance and Deficits in ShiftingCondition.

TRAIL MAKING TEST DISCREPANCIES

–3

–2.5

–2

–1.5

–1

–0.5

0

0.5

1

1.5

2


Z-SC

ORE

DKEFS Trails Motor SpeedDKEFS Trails Average of Num & Letter SequencingDEKFS Trails Number/Letter Sequencing + Shifting

6 5 4 3 2 1


D.H.’s case: Executive function and Memory tasks


D.H.’s case: Executive function and Memory tasks286 JACOBSON ET AL.

cm, 1.2 mm contiguous sections). Selected axial andcoronal slices reveal asymmetric atrophy in medialtemporal regions (Figure 9a), particularly in the lefthemisphere. The neuroradiologist’s impressionsdescribed generalized cortical atrophy greater intemporal lobe regions, ventricular enlargement,and no indication of significant ischemic changes,tumor or mass. A 3-dimensional reconstruction(Bigler et al., 2002) of the T1-weighted image is alsodepicted (Figure 9b) to illustrate cortical atrophyand ventricular enlargement.

DISCUSSION

The present case illustrates the diagnostic chal-lenges inherent in identifying preclinical AD whenan individual’s cognitive profile lacks many of the

typical hallmarks of this phase. Despite an even-tual diagnosis of probable AD after the sixth yearof participation, none of the first four assessmentswould justify an MCI diagnosis: her performanceson most individual cognitive tasks, including mem-ory tests, were within or above the average range,she was living independently, and she had no sub-jective memory complaints until the final assess-ment. With few exceptions (e.g., naming ability atthe fourth assessment), her performances on indi-vidual neuropsychological tests remained above alevel of impairment until the final year. Discrep-ancy scores have been used in many contexts as ameans of identifying subtle declines in cognitiveskills relative to those that are more resilient to aneurodegenerative process or dementia (Dori &Chelune, 2004; Finton et al., 2003; Ivnik et al.,2000; Wilde et al., 2001). Analysis of DH’s

Figure 6. Stroop Discrepancies: Color/word Naming Scores and Traditional Stroop Scores with Impaired Interference/SwitchingCondition.

COLOR WORD INTERFERENCE DISCREPANCIES

–3.5–3

–2.5–2

–1.5–1

–0.50

0.51

1.5


Z-SC

ORE

S

DKEFS Color naming/Word Reading Baseline DKEFS Interference conditionDKEFS Interference + Switching condition

6 5 4 3 2 1

Figure 7. CVLT Learning versus Vocabulary Discrepancies: Stable Basic-skill Word Knowledge Ability with Declining VerbalLearning Scores.

WORD KNOWLEDGE VERSUS VERBAL LEARNING

–3.5

–3

–2.5

–2

–1.5

–1

–0.5

0

0.5

1


Z-SCORE

Vocabulary CVLT Learning

6 5 4 3 2 1



D.H.’s case: Executive function vs Memory tasks

286 JACOBSON ET AL.

cm, 1.2 mm contiguous sections). Selected axial andcoronal slices reveal asymmetric atrophy in medialtemporal regions (Figure 9a), particularly in the lefthemisphere. The neuroradiologist’s impressionsdescribed generalized cortical atrophy greater intemporal lobe regions, ventricular enlargement,and no indication of significant ischemic changes,tumor or mass. A 3-dimensional reconstruction(Bigler et al., 2002) of the T1-weighted image is alsodepicted (Figure 9b) to illustrate cortical atrophyand ventricular enlargement.

DISCUSSION

The present case illustrates the diagnostic chal-lenges inherent in identifying preclinical AD whenan individual’s cognitive profile lacks many of the

typical hallmarks of this phase. Despite an even-tual diagnosis of probable AD after the sixth yearof participation, none of the first four assessmentswould justify an MCI diagnosis: her performanceson most individual cognitive tasks, including mem-ory tests, were within or above the average range,she was living independently, and she had no sub-jective memory complaints until the final assess-ment. With few exceptions (e.g., naming ability atthe fourth assessment), her performances on indi-vidual neuropsychological tests remained above alevel of impairment until the final year. Discrep-ancy scores have been used in many contexts as ameans of identifying subtle declines in cognitiveskills relative to those that are more resilient to aneurodegenerative process or dementia (Dori &Chelune, 2004; Finton et al., 2003; Ivnik et al.,2000; Wilde et al., 2001). Analysis of DH’s

Figure 6. Stroop Discrepancies: Color/word Naming Scores and Traditional Stroop Scores with Impaired Interference/SwitchingCondition.

COLOR WORD INTERFERENCE DISCREPANCIES

–3.5–3

–2.5–2

–1.5–1

–0.50

0.51

1.5


Z-SC

ORE

SDKEFS Color naming/Word Reading Baseline DKEFS Interference conditionDKEFS Interference + Switching condition

6 5 4 3 2 1

Figure 7. CVLT Learning versus Vocabulary Discrepancies: Stable Basic-skill Word Knowledge Ability with Declining VerbalLearning Scores.

WORD KNOWLEDGE VERSUS VERBAL LEARNING

–3.5

–3

–2.5

–2

–1.5

–1

–0.5

0

0.5

1


Z-SCORE

Vocabulary CVLT Learning

6 5 4 3 2 1




intra-individual differences revealed a consistentpattern of cognitive discrepancies that may havesignaled an impending decline despite generallyintact performances on individual tasks. DH’scomplex versus basic-level task discrepancy scoresreflected stable performance on more fundamentaltask components in the face of mild declines inexecutive function or memory abilities. Her verbalversus non-verbal discrepancies reflected an asym-metric decline in largely verbally mediated tasks.

Although the majority of DH’s discrepancyscores reflected at least a 2 SD difference by thefinal assessment, the question arises as to whatconstitutes an atypical discrepancy? There is a con-siderable body of literature addressing the questionof clinical versus statistical significance of cognitivediscrepancies (Crawford & Garthwaite, 2005;Crawford, Garthwaite, & Gault, 2007; Lange &Chelune, 2006; Lange, Chelune, & Tulsky, 2006).A commonly used criteria considers a discrepancy‘unusual’ or significant if it occurs in less than 10%of the population (Hawkins & Tulsky, 2001;Kramer et al., 2006), although methods for dis-crepancy score calculations vary. Fortunately,

many tests now incorporate discrepancy measures(e.g., CVLT-II, WAIS-III, D-KEFS, WarringtonRecognition Memory Test) as standardized varia-bles, although base rate information is not alwaysavailable. Chelune, Holdnack, and Levy (2006)examined D-KEFS normative data and found thata letter-category fluency scaled-score discrepancyof +3 occurs in 10% of the sample (with 13–15years of education). By comparison, DH’s letter-category fluency discrepancy (at age 82) showed ascaled score difference of 5, with a contrast scaledscore of 15 (95th percentile rank) based on hersame age peers in the D-KEFS sample. In additionto the discrepancy magnitude, the frequency of sig-nificant discrepancies is also a consideration.A pattern of large, recurring discrepancies that areinternally consistent may provide more convincingevidence of impending cognitive decline than a sin-gle, isolated discrepancy. For example, three signi-ficant discrepancy measures occurred in 2% of thein the CVLT-II normative sample, while a singlesignificant discrepancy occurred in 22% of the sam-ple (Donders, 2006). Finally, discrepancy scoresvary by IQ and education with higher functioning

Figure 8. Scatterplot and Trend Lines: Increasing Longitudinal Discrepancies in (a) Verbal/Spatial Discrepancies and (b) Basic-ability/Complex Task Discrepancies.

Mean Discrepancy Scores: Verbal vs. Spatial Task Contrasts

y = 0.3872x + 0.8046R2 = 0.643

00.5

1

1.52

2.53

3.5

(a)

(b)

4

1 2 3 4 5 6years

z-sc

ore

diffe

renc

e

Mean discrepancy scores:Combined Complex vs. Basic Task Contrasts

y = 0.3917x + 0.4275

R2 = 0.6927

0

0.5

1

1.5

2

2.5

3

3.5

1 2 3 4 5 6years

z-sc

ore

diffe

renc

e



D.H.’s case: Contributions

• Cognitive impairment can be masked in certain cases where declining scores remain above norm-based cutoff scores

• Serial assessments over time may improve detection of subtle cognitive changes in individuals

• Cognitive-discrepancy analysis may be beneficial in identifying normal-functioning elderly with preclinical AD


Questions?


References• Jacobson, Mark W., Delis, Dean C., Peavy, Guerry M., Wetter,

Spencer R., Bigler, Erin D., Abildskov, Tracy J., Bondi, Mark W. and Salmon, David P.(2009) 'The emergence of cognitive discrepancies in preclinical Alzheimer's disease: A six-year case study', Neurocase, 15: 4, 278 — 293, First published on: 21 April 2009 (iFirst)


dementia case study

Health & Medicine