How Types of Dementia Affect Neuropsychological Assessment of Competence and Capacity

Paper Presented at the Annual Conference of the American Psychology-Law Society, San Diego, California, March 20, 2015

In the clinical setting, “capacity” refers to the clinician’s judgment of seniors’ cognitive, decisional, affective, and practical abilities, especially when a lack of capacity puts their assets, property, or health at significant risk (Moye & Braun, 2010). In health care settings, capacity focuses mostly on medical consent, sexual consent, financial management, independent living, and driving. In the forensic setting, the focus is on financial capacity, testamentary capacity (capacity to execute a will), donative capacity, capacity to contract, and capacity to convey real property. Capacity also applies to criminal cases, such as capacity to stand trial or capacity for criminal responsibility. Other areas include one’s capacity to vote or to consent to participate in scientific or medical research.

While capacity refers to specific areas functioning, competency usually implies an “all or nothing” state (either one is competent or one is not), resulting in competency being less often considered in legal proceedings (Moye & Braun, 2010). However, when legal definitions of competency are considered, they often vary with circumstances. For example, competence may be defined narrowly when a senior seeks consent for a questionable and potentially dangerous medical procedure, but defined more broadly when a senior refuses to take a particular psychoactive medication (Melton et al., 2007).

As a legal term, capacity refers to a judicial finding regarding a senior’s abilities, raised in context of legal hearing or dispute, and in consideration of legal standard (Moye & Braun, 2010). All adults are presumed to have capacity in eyes of the law unless otherwise determined in a court of law, and to define incapacity the neuropsychologist should consider four elements: the disabling condition, cognitive impairment, functional impairment, and necessity (degree of risk and failure of less restrictive alternatives that necessitates a guardianship intervention). Courts are now less interested in overall diagnoses and more on “functional abilities” – how a disorder and its symptoms affect a senior’s strengths and weaknesses in decision-making and judgment and in independent activities of daily living (IADLs).

Legal capacity standards vary between states, and summaries of legal standards for common civil capacities can be found in handbook produced by the American Bar Association Commission on Law and Aging and the American Psychological Association (ABA & APA, 2008; www.apa.org/pi/aging). 

Testamentary Capacity

Testamentary capacity refers to a senior’s capacity to meet the legal threshold required to perform the task of writing a will (Melton et al., 2007). For seniors to be competent, they must be “of sound mind,” which encompasses four attributes: (1) knowing at time that they are making their will, (2) knowing in a general way (not every detail) of the nature and extent of their property, (3) knowing “the natural objects of their bounty” (their relationship with individuals who may naturally claim to benefit from the property left to them), and (4) knowing the “practical effect” of their will (the manner in which their will distributes their property). 

The law does not require “perfect” capacity or knowledge, only that a senior is above a determined threshold of functioning and has the requisite functional abilities at the time the will is executed. For example, if a senior has forgotten to include one particular family member as a beneficiary, this would not automatically invalidate the will, or if a senior with a florid mental illness executes a will during a “lucid interval,” the will may still be deemed valid. If a senior believes that a particular potential beneficiary has attempted to injure him or her, this would also not invalidate the will, unless it can be shown that the senior’s belief “has no basis in reason, cannot be dispelled by reason, and can be accounted for only as the product of a mental disorder” (Melton et al., 2007).

            If there is an issue of undue influence at the time a will was executed, the legal issue would focus on whether the senior’s distribution of property was too heavily influenced by a third party. Four factors determine the presence of undue influence, including: (1) a confidential relationship existed between senior and influencer (e.g., close relative or advisor), (2) the influencer used the relationship to secure a change in how the senior distributed the estate, (3) the change in the estate plan was unconscionable or did not reflect the true wishes of senior, and (4) the senior was susceptible to being influenced (which would need to be clinically determined). 

Medical Decision Making Capacity

Medical decision making is a specific capacity in which informed consent for medical treatment must be voluntary (the senior must not have been coerced) and knowledgeable (the senior must be informed about condition, treatments, and alternatives), and the senior must have the capacity to make the decision (Moye & Braun, 2010). The Uniform Health Care Decisions Act (1993) defines medical consent capacity as a senior’s “ability to understand the significant benefits, risks, and alternatives to proposed health care and to make and communicate a health care decision.” State-specific definitions regarding medical consent capacity are often located in advance directive statutes, durable power of attorney statutes, and in the body of case law.

            There are four functional elements in legal standards for medical consent, including understanding, appreciation, reasoning, and expressing a choice (Moye & Braun, 2010):

  • “Understanding” is the ability to comprehend diagnostic and treatment-related information, including not only the ability to remember newly presented words and phrases, but also the ability to demonstrate one’s comprehension of the information to a physician or evaluator.
  • "Appreciation” is the cognitive and emotional belief in the nature of the diagnosis, that the belief is based on accurate information, and that the treatment applies to one’s situation.
  • "Reasoning” is the process of deciding on a treatment by comparing alternatives in light of consequences, and through integrating, analyzing, and manipulating information, including drawing inferences about the impact of alternatives on everyday life and considering one’s own personal values and preferences.
  • "Expressing a Choice” is the ability to communicate one’s decision about the treatment, and applies mostly to seniors who either cannot or will not express a choice, or who choose to remain ambivalent.

A senior may choose to execute an Advance Healthcare Directive (Health Care Proxy), which names a person to make health care decisions if the senior is unable to do so during and/or following medical treatment. During the process of evaluating capacity, the neuropsychologist may wish to disclose each element of document, and then ask questions to ascertain the senior’s degree of understanding, such as: What is an advance directive? What will your health care proxy do for you? Who would you choose as the person to make decisions for you? Why would you choose or trust this person? What is a living will? Why do you want to do it? What happens if you get worse and you are unable to speak for yourself? (Moye & Braun, 2010). 

Of ethical significance is whether decisions by appointed caregivers on behalf of the senior are made in accordance to the senior’s values, preferences, and best interests, especially when those values and preferences change as a result of the symptoms of dementia (Chiong, 2013). As the disease progresses, changes in personal, philosophical, and religious beliefs may be in conflict with the senior’s past decisions in an advance directive, posing a moral and ethical challenge for the appointed caregiver. For example, how does the caregiver respond to a senior’s current request that all measures are taken to keep him or her alive, when the senior’s original directive at the time he or she was competent was that no heroic measures be taken?

Financial Capacity

Financial capacity is a senior’s ability to make decisions regarding a number of financial tasks, such as general financial management of assets and debts, writing checks, paying bills, knowing and using currency and coin, making contracts, and writing wills (Marson, 2013). Financial capacity also relates to more specific legal capacities, such as contractual capacity, donative capacity, and testamentary capacity, and so is the basis for determining conservatorship (or guardianship) of the senior’s estate.

Decisions regarding financial capacity should take into consideration the senior’s financial experience, which can vary widely based on the senior’s education, culture, religion, and socioeconomic status. Cognitive components of financial capacity include verbal conceptual knowledge and memory, as well as visual attention and scanning, visual memory, mental and written arithmetic abilities, executive abilities (e.g., organizing and retaining tax documents), and procedural learning (using a checkbook register or an ATM). 

Capacity for Independent Living

Three functional elements associated with independent living are understanding, application, and judgment (APA, 2008):

  • "Understanding” refers to the basic abilities necessary to live independently, such as paying utility bills on time, grocery shopping, kitchen safety (not leaving the stove on), taking medications, and the ability to foresee potential problems in not performing these tasks.
  • "Application” refers to cognitive insight in recognizing that certain tasks must be done (e.g., personal hygiene, doing the dishes, feeding and cleaning up after pets), and the willingness to accept help if one is unable to perform these tasks.
  • "Judgment” is the senior’s ability to consistently follow through on performing tasks or on asking for help, and to avoid high-risk behaviors when alone or responding to emergency situations (e.g., a kitchen fire). Seniors with cognitive, emotional, or thought disorders are often unmotivated to perform IADLs or to seek assistance from others, and often cannot accurately foresee the potential consequences of not performing day-to-day tasks related to home safety and personal survival.

The neuropsychologist must determine to what extent cognitive deficits will affect the senior’s ability to live alone, and confirm what adjustments should be made to the senior’s environment to enhance cognitive strengths. The senior must demonstrate the ability to be alert enough to know that things need to be done and to actively plan on doing them. The senior should recall when events occurred and which ones did not, and understand which items are at home, what needs to be replaced, and what precautions need to be taken. Seniors should be able to read labels on food and medications, to communicate with others, or understand what others are saying, or to direct another person to perform tasks or assist with their personal care. Seniors should also be able to manage their medications, manage their money and finances, and maintain their overall health, safety, and well-being.

Neuropsychologist’s Role in Capacity Evaluation

The neuropsychologist forms an opinion regarding capacity after considering functional skills relevant to capacity in question, cognitive functioning, psychiatric functioning, medical diagnoses and prognoses, the senior’s values, and situational risks relevant to capacity. Clinical findings and capacity judgments are framed within the general context of applicable legal standards, and clinical findings are closely linked to decisional framework and processes of court. All decisions regarding capacity should be understood in context of the senior’s lifestyle or life patterns, values, culture, and religious preferences, which may vary depending on the senior’s age, sexual orientation, race, ethnicity, gender, culture, religion, or other life experience that informs life perspective. The senior’s core values may impact preferences for who is named guardian, medical decisions, financial decisions, and living arrangements (ABA & APA, 2008).

The American Bar Association and American Psychological Association Handbook for Psychologists (2008) outlines nine components necessary for clinical capacity assessment of older adults: (1) Legal Standard; (2) Functional Elements; (3) Diagnosis; (4) Cognitive Underpinnings; (5) Psychiatric or Emotional Factors; (6) Values; (7) Risk Considerations; (8) Steps to Enhance Capacity; and (9) Clinical Judgment of Capacity (ABA & APA, 2008). The neuropsychologist’s report should include relevant diagnoses with explicit discussion of prognoses and recommendations for reevaluation, capacity conclusions that integrate functional findings with cognitive and psychiatric data in view of values and risks considerations, and recommendations for management and treatment.

            In order to determine capacity, the neuropsychologist examines the following areas of functioning (ABA & APA, 2008):

  • Sensory Acuity: Examining the ability to hear, see, smell, and touch confirms how sensory deficits impact seniors’ functioning in their environments.
  • Motor Activity (active, agitated, slowed) and motor skills (gross and fine): Examining visual, auditory, and tactile stimuli confirms the extent to which seniors’ motor deficits impact functioning in their environment.
  • Attention: Examining a senior’s ability to attend to tasks is an important first step in completing an assessment, and one’s inability to do so may indicate a state of delirium, hypersomnia, or other impairment in subcortical functioning.
  • Language: Examining one’s ability to express a choice is a critical component of capacity assessments. Complex medical and financial decisions require an ability to read and comprehend written documents, and speech production, language comprehension, and written language skills are necessary components in establishing legal capacity.
  • Memory: Memory disorders impair decision-making by disrupting the senior’s ability to recall previously learned information, integrate information across choice options, and learn new information.
  • Speed of Processing: Slowed speed of processing can result in poor decision making, especially in context of coercive interactions in cases of undue influence.
  • Executive Functioning: The senior’s ability to plan, think flexibly, respond to feedback, and inhibit impulsive responses is critical to decision making capacity.
  • Judgment and Reasoning: Examining the distinction between one’s responses to posed problems and one’s abilities to implement them is critical to determining capacity for making a decision. For example, when posed the hypothetical problem “What would you do if you saw smoke and fire in the home,” a senior may answer “run and put it out,” even though the senior had significant mobility issues.
  • Arithmetic or Mathematical Skills: Understanding basic quantities and making simple calculations are important for financial decision making and in performing daily financial tasks.
  • Visual-Spatial and Visual-Constructional Reasoning: Includes visual-spatial perception and visual problem solving, which are important for functioning in the home and community and an essential component of driving capacity.
  • Insight: Often considered a part of executive functioning, seniors should be able to acknowledge their deficits and the potential benefits of intervention, and be willing to accept help in order to use home services.
  • Psychopathology: Assessment should include identification of symptoms associated with depressed or anxious mood, including insomnia, fatigue, low energy, low appetite, loss of interest or pleasure, irritability, feelings of helplessness, worthlessness, hopelessness, or suicidal ideation, as well as assessing symptoms of thought disorders, including delusions, hallucinations, and/or irrational, hostile, and aggressive behaviors.
  • Personality Inventories: Occasionally used in capacity assessment to explore unusual interpersonal interactions or reality judgments that may impact sound decision making.
  • Tests of Effort, Motivation, or Response Style:  Serve as one type of evidence in judging the validity of overall cognitive testing, and making a clinical judgment regarding the meaning associated with intentional (or in some cases subconscious) test-taking approach to exaggerate (or hide) deficits.

The neuropsychologist’s report should take into consideration six main areas upon which judges most often base their decisions regarding a senior’s capacity: cognitive functioning, functional independence, ability to maintain values, risk of harm to self or others, required level of supervision, and possible accommodations to compensate for lack of capacity (ABA & APA, 2006).

Streisand and Spar (2008) discuss three key principles for evaluating decisional capacity in seniors with dementia:

  • Confirming impairment in cognitive functioning, including attention and concentration, immediate, recent and remote memory, language comprehension and expression, ability to calculate, capacity for abstract thinking, reasoning and planning, general fund of knowledge, and nonverbal skills.
  • Timing of the evaluation, which should be as close as possible to the date that the decision (e.g., execution of a will) was made. A long time period between evaluation and decision-making increases the possibility of changes in mental status, thus making the capacity evaluation moot.
  • Avoidance during testing of any extraneous factors that may compromise cognitive performance, such as testing environment (e.g., poor lighting, distracting noises), senior factors (e.g., emotional distress, medication side-effects, excessing sleepiness), or examiner factors (any technique that either provokes anxiety or fails to evoke a reasonably representative performance).

Types of Dementia

There are several neuropathologically distinct age-related neurodegenerative disorders, each of which has a discrete pattern of cognitive deficits that help the neuropsychologist determine a senior’s levels of capacity in various areas (Salmon & Bondi, 2009). While normal age-related cognitive decline can negatively affecting a senior’s working memory, processing speed, and sensory and perceptual abilities, it rarely results in a significant lack of decisional capacity, although it may still increase a senior’s vulnerability to undue influence (Streisand & Spar, 2008). 

Alzheimer's Disease (AD)

Alzheimer’s disease (AD), seen in approximately 70% of seniors with dementia, is caused by a progressive brain disease involving protein deposits in brain and disruption of neurotransmitter systems. Symptoms includes initial short-term memory loss, followed by problems in language and communication, orientation to time and place, everyday problem solving, and eventually recognition of people and everyday objects. In the early stages, a senior may retain some decisional and functional abilities, but central nervous system deterioration is progressive and irreversible, resulting ultimately in death in roughly 8-10 years (ABA & APA, 2008).

            Seniors with early AD have impairment in delayed recall (abnormally rapid forgetting), including impairment in effectively transferring information from primary to secondary memory stores, and have problems with proactive interference, or difficulty recalling new information immediately after the occurrence of prior learning (Salmon & Bondi, 2009). Seniors with AD have a true and insidious loss of semantic memory (for facts and general information) and episodic memory (for past events and experiences), running in reverse from the most recently acquired information to the most remote knowledge from the past. They begin to lose capacity for critical self-awareness, leading to an increasing lack of awareness of the extent of their cognitive deficits (called anosognosia).

Later stages of AD include significant impairment in memory, orientation to time and place, recognition of familiar people, and functional abilities such as bathing, dressing, and eating. Significant language impairment also affects seniors’ abilities to communicate their needs to family members, physicians, and caregivers. They often experience dysfluency of speech with paraphasias (unintended syllables, words, or phrases), bizarre word combinations, and intrusions, and impairment in visual memory and visuospatial orientation. Development of aphasia (impairment in speech) and apraxia (impairment in motor planning to perform movements or tasks) can affect capacity for independent living, including driving capacity. Development of agnosia (difficulty recognizing objects despite intact sensory abilities) can also affect a senior’s financial capacity. Later impairment in executive function can both testamentary capacity and medical decision-making (Manning & Ducharme, 2010).

While neurocognitive changes occur gradually, often over several years, the senior with AD will eventually cross a threshold where cognitive deficits become global and severe enough to interfere with normal functioning, at which point the senior’s capacities are called into question. The goal of capacity evaluations for seniors with AD is to establish a pattern of neurocognitive deficits based on the relevant statutory criteria for capacity. The evaluation need not determine seniors’ actual knowledge and understanding of facts and events, but rather their ability to learn, recall, and comprehend information presented in order to make a reasoned decisions regarding executing a will, accepting or refusing medical care, engaging in financial tasks, or living independently in safety and security.

Lewy Body Dementia

Lewy body dementia (DLB) occurs in approximately 20% of dementia cases, and is characterized by neurocognitive impairment caused by deposition of Lewy bodies (abnormal intracytoplasmic eosinophilic neuronal inclusion bodies) in subcortical structures of the brain, including the limbic system and neocortex. Symptoms include mild spontaneous Parkinsonian motor deficits (e.g., bradykinesia and rigidity), but with no resting tremors commonly seen in individuals with Parkinson’s disease. There are also recurrent and well-formed visual hallucinations and severe fluctuations in arousal, attention, and cognitive functioning. Rapid eye movement (REM) sleep behavior disorder, in which seniors physically act out their dreams while sleeping, occurs in about 50% of seniors with DLB (Josif & Graham, 2008). 

About 80% of seniors with DLB have well-formed, three-dementional, detailed, and colorful visual hallucinations (Josif & Graham, 2008; Manning & Ducharme, 2010). The hallucinations are typically non-threatening, and are either misrepresentations of objects in a room (e.g., seeing a rumpled towel as a white rabbit), or as a clearly define person who appears real but does not visually acknowledge or speak to the senior (which would more likely occur in individuals with psychosis). Of considerable concern is that seniors with DLB respond poorly (often with extrapyramidal side effects) to neuroleptic medications, which are very often given by clinicians in response to reports of visual hallucinations. 

Parkinsonian symptoms, which occur in approximately 75% of seniors with DLB, usually present one year prior to the onset of noticeable cognitive impairment (Josif & Graham, 2008; Manning & Ducharme, 2010). Symptoms include poor regulation of body function (resulting in dizziness, gait instability, impotence, falls from orthostatic hypotension, and swallowing difficulties), extrapyramidal symptoms (e.g., motor restlessness, irregular muscle movements, and muscle rigidity), and akinesia (reduced control of voluntary muscle movements). Pathological changes in the occipital cortex and accompanying pathways result in severe visual-spatial, visual-perceptual, and visual-constructional impairments significantly greater than in seniors with AD, all of which can have a significant negative impact on driving capacity and capacity for IADLs (Salmon & Bondi, 2009). 

Seniors with DLB usually have less severe impairment in memory encoding and retention than those with AD due to less severe damage to medial temporal lobe structures, but greater deficits in memory retrieval due to frontostriatal impairment (Salmon & Bondi, 2009). Seniors with DLB often also have greater deficits than those with AD in attention and executive function, caused by accumulation of Lewy bodies in the frontal lobes and by basal ganglia impairment that interrupts signals through frontostriatal circuits to the forebrain. As a consequence, they have greater impairment in decision making, calling into question their testamentary, medical, and financial capacity.

Cognitive fluctuations, which occur in approximately 75% of seniors with DLB, are periods of behavioral confusion, inattention, and incoherent speech alternating with episodes of lucidity and capable task performance, with each period lasting minutes, weeks, or months (Trachsel et al, 2014). These episodes occur spontaneously and are apparently not caused by environmental triggers or stressors (Bradshaw et al., 2004).  The neuropsychologist must address these fluctuations in neurocognitive functioning during capacity evaluations. For example, assessment results from a senior who exhibits lucidity and cognitive clarity in the morning hours may be considered valid measures of the senior’s capacity, but results may not be valid if that same senior experiences inattention and confusion in the afternoon. The neuropsychologist should also confirm that periods of apparent inattention and confusion are not the result of fatigue, hypersomnia, or side-effects of medication.

Frontotemporal Dementia

Frontotemporal dementia (FTD), occurring in approximately 6% to 12% of seniors with dementia, is one of three types of frontotemporal lobe dementias, the other two being semantic dementia and primary progressive aphasia. Subtypes of FTD include Pick’s disease and familial chromosome 17-linked frontal lobe dementia (Manning & Ducharme, 2010). FTD typically begins with insidious but profound changes in personality and social behavior (e.g., inappropriate social conduct, tactlessness, increase in apathy, disinhibition, loss of empathy, perseverative behavior, loss of insight, lack of judgment, decreased speech output, and decline in personal hygiene), which are often initially suspected to be psychiatric disturbances rather than dementia, especially in light of earlier age of onset (between 40 and 65 years of age).

Later symptoms of FTD include extrapyramidal changes, such as tremor, muscle rigidity, and akinesia, and neurocognitive impairment in executive function and attention, while visuospatial abilities, reasoning skills, and memory remain relatively intact (ABA & APA, 2008; Salmon & Bondi, 2009). Unlike the other variants of frontal lobe dementias, progressive nonfluent aphasia (difficulty with smooth, fluid word production) and semantic dementia (fluent speech, but devoid of meaning), language in seniors with FTD is relatively preserved (Manning & Ducharme, 2010).

Seniors with FTD demonstrate greater executive function impairment than those with AD, which may be a strong predictor of incapacity. Lesions in the anterior cingulate, medial frontal cortex, and dorsolateral prefrontal cortex often result in a lack of motivation, drive, and emotional control necessary for planning and abstract thought, and orbitofrontal impairment often leads to erratic behavior and loss of emotional control. Executive dysfunction affects a senior’s ability to cognitively and morally understand presented information, weigh the pros and cons of that information, and then make a final reasoned decision. Difficulties in adapting to change can pose a challenge when faced with complex planning processes necessary to make decisions related to complicated legal, medical, financial, or life planning issues (Álvaro, 2012).. 

While seniors with FTD may present clinically as cognitively intact and often maintain normal intellectual functioning, relatives and caregivers often report severe negative changes in behavior and significant impairment in real-life decision making, including difficulties in planning daily tasks and future events, inappropriate choices of friends and activities, making financial decisions that lead to bankruptcy, and engaging in behaviors that lead to legal problems (Manes et al., 2010). Patients with FTD are more likely to make decisions based upon instant gratification and short-term reward, while ignoring potentially negative long-term risks to their social relationships, personal finances, and overall health and well-being. This poses a problem in determining legal capacity, which is based on neurocognitive impairments that prevent a senior from making proper decisions, not a senior’s cognitively intact decisions to engage in inappropriate or even unlawful behaviors.

Vascular Dementia

Vascular dementia (VaD) is not a neurodegenerative disease, but a consequence of infarctions, ischemic injury, or hemorrhagic lesions occurring in the brain following a number of cerebrovascular events (Salmon & Bondi, 2009). Common risk factors are those that normally lead to these events, including high blood pressure, high cholesterol, coronary heart disease, peripheral artery disease, diabetes, and smoking. Symptoms vary considerably based on the cause and location of damage in the brain, occur with sudden onset after a cerebrovascular event, and then plateau until the next event, with each new event producing additional cognitive impairment (Manning & Ducharme, 2010). Symptoms appear gradually and in a stepwise fashion, and are often not noticed by the individual or family members for some time, but when enough brain tissue is damaged cognitive and functional impairments become severe enough to warrant a diagnosis of VaD (Streisand & Spar, 2008). 

Memory in individuals with VaD is relatively spared with better recall and recognition than in those with AD. Impairment in executive function is usually related to frontal subcortical dysfunction, leading to difficulties in problem solving, focused attention, processing speed, and visual-constructional abilities (Manning & Ducharme, 2010; Salmon & Bondi, 2009). Increased levels of apathy consistent with frontal subcortical damage in individuals with VaD often results in decreased capacity in performing activities of daily living. Because individuals with VaD have greater cognitive abilities than those with AD, their greater awareness often leads to higher incidences of anxiety and depression. 

            Unlike evaluating individuals with progressive dementias, evaluating capacity in individuals with VaD is based only on the individual’s current levels of capacity, and no true predictions can be made regarding their future neurocognitive functioning. While there may a potential and possible likelihood of additional cerebrovascular events, until such events occur it must be assumed that the individual’s capacity will remain constant. Therefore, with less possibility of changes in mental status, a relatively longer time period can elapse between an individual’s decision making (e.g., executing a will) and the performance of a capacity evaluation without the evaluation being considered moot or void.

Huntington’s Disease

Huntington’s disease (HD) is an inherited, autosomal dominant disease often appearing in midlife (ages 30-40 years). It is often described as a “subcortical” dementia based on symptoms of impaired attention, slowness of thought, executive dysfunction, poor learning, visual-perceptual and visual-constructional deficits, and personality changes such as apathy and depression. Other symptoms include the development of movement disorders (e.g., chorea, dysarthria, gait disturbance, oculomotor dysfunction), behavioral changes (e.g., depression, irritability, anxiety) and dementia (Salmon & Bondi, 2009). These deficits arise primarily from a progressive deterioration of the neostriatum and accompanying projections to the frontal cortex that influence both motor control and higher cognitive functions. 

While seniors with AD have severe deficits in episodic memory and difficulties in consolidating new information, individuals with HD have a mild-to-moderate memory impairment resulting mostly from impairment in encoding and retrieving information, but not in retaining information in their memory stores (Salmon & Bondi, 2009). Relatively early in the course of HD, all aspects of working memory are more significantly affected including the maintenance of information in the temporary memory buffers, inhibition of irrelevant information, and the use of strategic aspects of memory such as planning and organization, while similar impairment in working memory occurs only in later stages of AD. 

Individuals with HD experience significant impairment in executive function that progresses throughout their illness, including planning and problem solving, goal-directed behavior, the ability to generate multiple response alternatives, the capacity to resist distraction and maintain response set, and the cognitive flexibility to evaluate and modify their behavior (Salmon & Bondi, 2009). 

References 

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American Bar Association Commission on Law and Aging & American Psychological Association. (2008). Assessment of older adults with diminished capacity: A handbook for psychologists. Washington, DC: American Bar Association.

American Bar Association Commission on Law and Aging & American Psychological Association (2006). Judicial determination of capacity of older adults in guardianship proceedings. Washington, DC: American Bar Association.

Bradshaw J, Saling M, Hopwood M, Anderson V, Brodtmann A. (2004). Fluctuating cognition in dementia with Lewy bodies and Alzheimer’s disease is qualitatively distinct. Journal of Neurological and Neurosurgical Psychiatry, 75, 382-387.

Chiong, W. (2013). Dementia and personal identity: Implications for decision-making. In: J. L. Bernat & R. Beresford (Eds.), Handbook of Clinical Neurology, Vol. 118 (Ethical and Legal Issues in Neurology). New York: Elsevier, pp. 409-418.

Josif, S. J, & Graham, K. (2008).. The diagnosis and treatment of dementia with Lewy bodies. Journal of the American Academy of Physician Assistants, 21, 22-26 

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Manning, C. A., & Ducharme, J. K. (2010). Dementia syndromes in the older adult. In: P. A. Lichtenberg (Ed.). Handbook of assessment in clinical gerontology. (2nd Ed.). London: Academic Press, pp. 155-178.

Melton, G. B., Petrila, J., Poythress, N. G., & Slobogin, C. (2007). Psychological evaluations for the courts (3rd Ed.). New York: Guilford Press.

Salmon, D. P., & Bondi, M. W. (2009). Neuropsychological Assessment of Dementia. Annual Review of Psychology, 60, 257-282.

Streisand, A. F., & Spar, J. E. (2008). A lawyer's guide to diminishing capacity and effective use of medical experts in contemporaneous and retrospective evaluations. ACTEC Journal, 33, 180-194.

Trachsel, M., Hermann, H., & Biller-Andorno, N. (2014). Cognitive Fluctuations as a Challenge for the Assessment of Decision-Making Capacity in Clients with Dementia. American Journal of Alzheimer’s Disease & Other Dementias, pp. 1-4. Downloaded from aja.sagepub.com at UCLA on January 1, 2015. DOI: 10.1177/1533317514539377