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8.88: Dementia of the Alzheimer’s Type (294.1x)

  • Page ID
    23284
  • Diagnostic criteria

    A. The development of multiple cognitive deficits manifested by both

    (1) memory impairment (impaired ability to learn new information or to recall previously learned information)

    (2) one (or more) of the following cognitive disturbances:

    • aphasia (language disturbance)
    • apraxia (impaired ability to carry out motor activities despite intact motor function)
    • agnosia (failure to recognize or identify objects despite intact sensory function)
    • disturbance in executive functioning (i.e. planning, organizing, sequencing, abstracting)

    B. The cognitive deficits in Criteria A1 and A2 each cause significant impairment in social or occupational functioning and represent a significant decline from a previous level of functioning.

    C. The course is characterized by gradual onset and continuing cognitive decline.

    D. The cognitive deficits in Criteria A1 and A2 are not due to any of the following:

    (1) other central nervous system conditions that cause progressive deficits in memory and cognition (e.g. cerebrovascular disease, Parkinson’s disease, Huntington’s disease, subdural hematoma, normal-pressure hydrocephalus, brain tumor)

    (2) systemic conditions that are known to cause dementia (e.g. hypothyroidism, vitamin B12 or folic acid deficiency, niacin deficeincy, hypercalcemia, ceurosyphilis, HIV infection)

    (3) substance-induced conditions

    E. The deficits do not occur exclusively during the course of a delirium.

    F. The disturbance is not better accounted for by another Axis I disorder (e.g. Major Depressive Disorder, Schizophrenia).

    Code based on presence or absence of a clinically significant behavioral disturbance:

    • 294.10 Without Behavioral Disturbance: if the cognitive disturbance is not accompanied by any clinically significant behavioral disturbance.
    • 294.11 With Behavioral Disturbance: if the cognitive disturbance is accompanied by a clinically significant behavioral disturbance (e.g., wandering, agitation).

    Specify subtype:

    • With Early Onset: if onset is at age 65 years or below
    • With Late Onset: if onset is after age 65 years

    Coding note: Also code 331.0 Alzheimer’s disease on Axis III. Indicate other prominent clinical features related to the Alzheimer’s disease on Axis I (e.g., 293.83 Mood Disorder Due to Alzheimer’s Disease, With Depressive Features, and 310.1 Personality Change Due to Alzheimer’s Disease, Aggressive Type).

    Associated Features

    • Dementia of Alzheimer’s Type is increasingly diagnosed in individuals with Down Syndrome and those with a history of head trauma. Brain atrophy is present in the majority of individuals diagnosed with Dementia of Alzheimer’s Type, and they generally have wider cortical sulci and larger cerebral ventricles than would be expected given the normal aging process.
    • Few motor and sensory signs are seen in the first years of illness. Also, myoclonus and gait disorder may appear as the illness progresses. 10% of individuals with Dementia of the Alzheimer’s Type begin having seizures.

    Child vs. Adult presentation

    This disorder is not seen in children, it is present in adults only. Very few cases are seen before age 50. Late onset of Dementia of Alzheimer’s Type is more typical than early onset, meaning that the age of onset is typically after age 65 years.

    Epidemiology

    The prevalence rates of Dementia of Alzheimer’s Type increases dramatically with increasing age, rising from .6% in males and .8% in females at age 65 to 11% in males and 14% in females by age 85. As age increases so do the prevalence rates; at age 90 the rates rise to 21% in males and 25% in females, and by age 95 the prevalence rates are as high as 36% in males and 41% in females. Unfortunately, 40%-60% are moderate to severe cases.

    DSM-5 proposed changes (DSM5.org)

    1. Removing the term “Dementia” and adding “Major Neurocognitive Disorders”
    2. Adding a category of “Minor Cognitive Disorders”
    3. Categorizing behavioral disturbances, particularly the syndromes of psychosis and depression, associated Neurocognitive Disorders
    4. Selecting specific domains as well as measures of severity of cognitive functional impairment

    Major Neurocognitive Disorder (DSM-5)

    Disorders subsumed under this overarching category would include, but not limited to, the following: Dementia Due to a General Medical Condition, Dementia Not Otherwise Specified, Dementia of the Alzheimer’s Type, Vascular Dementia, Dementia Due to Multiple Etiologies, Amnestic Disorder Due to a General Medical Condition, and Amnestic Disorder Not Otherwise Specified. Some individuals meeting criteria for Cognitive Disorder Not Otherwise Specified may also meet criteria for this disorder. Certain specific etiologies would be coded as subtypes, such as the Alzheimer’s Disease Subtype of Major and Minor Neurocognitive Disorders.

    Major Neurocognitive Disorder
    A. Evidence of significant cognitive decline from a previous level of performance in one or more of the domains outlined above based on:
    1. Reports by the patient or a knowledgeable informant, or observation by the clinician, of clear decline in specific abilities as outlined for the specific table above.
    AND
    2. Clear deficits in objective assessment of the relevant domain (typically > 2.0 SD below the mean [or below the 2.5th percentile] of an appropriate reference population [i.e., age, gender, education, premorbid intellect, and culturally adjusted])

    B. The cognitive deficits are sufficient to interfere with independence (e.g., at a minimum requiring assistance with instrumental activities of daily living, i.e., more complex tasks such as finances or managing medications)
    C. The cognitive deficits do not occur exclusively in the context of a delirium.

    D. The cognitive deficits are not wholly or primarily attributable to another Axis I disorder (e.g., Major Depressive Disorder, Schizophrenia)
    Rationale for Change

    Major Neurocognitive Disorder (including what was formerly known as Dementia) is a disorder with greater cognitive deficits in at least one (typically two or more) of the following domains:
    Complex attention (planning, decision-making, working memory, responding to feedback/error correction, over-riding habits, mental flexibility),
    Executive ability (planning, decision-making, working memory, responding to feedback/error correction, overriding habits, mental flexibility),
    Learning and memory(immediate memory, recent memory [including free recall, cued recall, and recognition memory])
    Language(expressive language [including naming, fluency, grammar and syntax] and receptive language),
    Visuoconstructional-perceptual ability (construction and visual perception),and
    Social cognition (recognition of emotions, theory of mind, behavioral regulation).
    The cognitive deficits must be sufficient to interfere with functional independence. Important changes from the DSM-IV criteria include: change in nomenclature (MNCD or Dementia), not necessarily requiring memory to be one of the impaired domains, allowing cognitive deficit limited to one domain. In the introductory text, we offer a table that offers more details about the assessment of each domain in the form of specific symptoms of decline that can be elicited or observed, and assessment procedures that can be used to document the cognitive impairment and quantify its severity.

    • The term “dementia” is replaced by Major Neurocognitive Disorder, which is conceptualized as including what was formerly known as dementia as well as entities like amnestic disorder. “Dementia” is an accepted term for older adults (e.g., with Alzheimer’s disease)—although even in this setting it has acquired a pejorative or stigmatizing connotation, it is less well accepted among younger adults with deficits related to e.g., HIV or head injury.
    • This rewording focuses on decline (rather than deficit—consistent with the requirement in the basic definition of an acquired disorder) from a previous level of performance.
    • The previous criteria for dementia used Alzheimer’s disease as their prototype and thus required memory impairment as a criterion for all dementias. There is growing recognition that, in other neurocognitive disorders (e.g., HIV-related cognitive decline, cerebrovascular disease, frontotemporal degeneration, traumatic brain injury, etc.), other domains such as language or executive functions may be impaired first, or exclusively, depending on the part of the brain affected and the natural history of the disease.
    • The terminology for the cognitive domains has been updated to reflect current usage in neuropsychology and neurology.
    • The new definition, consistent with DSM-wide changes, focuses first on performance rather than disability. In the introductory table, we provide for each domain examples of specific symptoms or observations consistent with the Major level of decline and objective assessments. This encourages the use of objective measures, including formal neuropsychological testing where feasible with lesser exclusive reliance on individual judgment.
    • The presence of both symptoms/observations and objective assessment is included to ensure specificity. This is a larger issue for Minor Neurocognitive Disorder but included here for parallel structure of the criteria.

    NOTE: The committee is in the process of refining criteria A1 and A2 to achieve a balance between preferred formal neuropsychological assessment and what may feasible in some clinical settings. They welcome input on this issue.

    • The new language preserves the traditional function-based threshold for dementia but tries to operationalize it more clearly as a loss of independence.

    NOTE: The committee is still refining criterion D and discussing to what extent Major Neurocognitive Disorder should be diagnosed in the setting of disorders like schizophrenia and depression (although this concern applies primarily to Minor Neurocognitive Disorder). They also realize that issues of this nature are being addressed at the DSM-wide level, and are awaiting input of these larger discussions, as well as public input on this issue.

    Minor Neurocognitive Disorder(DSM-5)

    A. Evidence of minor cognitive decline from a previous level of performance in one or more of the domains outlined above based on:
    1. Reports by the patient or a knowledgeable informant, or observation by the clinician, of minor levels of decline in specific abilities as outlined for the specific domains above. Typically these will involve greater difficulty performing these tasks, or the use of compensatory strategies.
    AND
    2. Mild deficits on objective cognitive assessment (typically 1 to 2.0 SD below the mean [or in the 2.5th to 16th percentile] of an appropriate reference population (i.e., age, gender, education, premorbid intellect, and culturally adjusted). When serial measurements are available, a significant (e.g., 0.5 SD) decline from the patient’s own baseline would serve as more definitive evidence of decline.
    B. The cognitive deficits are not sufficient to interfere with independence (Instrumental Activities of Daily Living are preserved), but greater effort and compensatory strategies may be required to maintain independence.
    C. The cognitive deficits do not occur exclusively in the context of a delirium.

    D. The cognitive deficits are not wholly or primarily attributable to another Axis I disorder (e.g., Major Depressive Disorder, Schizophrenia).
    Rationale for Change

    Minor Neurocognitive Disorder has been added to recognize the substantial clinical needs of individuals who have mild cognitive deficits in one or more of the same domains but can function independently (i.e., have intact instrumental activities of daily living), often through increased effort or compensatory strategies. This syndrome, known in many settings as Mild Cognitive Impairment may be particularly critical, as it may be a focus of early intervention. Early intervention efforts may enable the use of treatments that are not effective at more severe levels of impairment and/or neuronal damage, and, in the case of neurodegenerative disease, may enable a clinical trial to prevent or slow progression.

    • Minor Neurocognitive Disorder is added to account for individuals with minor levels of cognitive impairment who may require assessment and treatment, but are not sufficiently impaired the Major diagnosis. To some extent, this entity will take care of individuals currently coded as Cognitive Disorder NOS without specific criteria. This change is driven by the need of such individuals for care, and by clinical; epidemiological; and radiological, pathological and biomarker research data suggesting that such a syndrome is a valid clinical entity with prognostic and potentially therapeutic implications. Prime examples are the prevalent neurocognitive disorders associated with various neuromedical conditions such as traumatic brain injury, HIV, substance-use-related brain disorders, diabetes, and early/mild stages of neurodegenerative disorders like Alzheimer’s disease and of cerebrovascular disease. As these conditions are increasingly seen in clinical practice, clinicians have a pressing need for reliable and valid diagnostic criteria in order to assess them and provide services including treatment of associated mood symptoms, further investigation of brain function, identification of treatable causes, and, for progressive disorders, appropriate early interventions.
    • The Neurocognitive Disorders Work Group is aware that the specific term “minor” can be challenged on the grounds that it implies lack of need for services and are open to alternative suggestions. They chose “minor” rather than “mild” to be parallel with “major” and to be able to maintain the mild, moderate, and severe distinction within Major NCD.
    • The combination of symptoms/observations and objective assessment is critical in Minor Neurocognitive Disorder to maintain specificity: a report of a change in abilities protects against overcalling the disorder in those with lifelong poor performance (sincedecline can only be inferred from a single observation), and objective assessment protects against overcalling the disorder in “the worried well.”
    • The Neurocognitive Disorders Work Group is in the process of refining these criteria to achieve a balance between preferred formal neuropsychological assessment and what may be feasible in some clinical settings. The issue is particularly difficult for Minor Neurocognitive Disorder because at lesser levels of cognitive impairment symptom reports may be unavailable or unreliable, observation may be less informative, the interpretation of objective assessments is complicated by variable premorbid abilities, and simpler assessments are likely to be insensitive. They welcome input on this issue.
    • The Neurocognitive Disorders Work Group is still refining criterion D and discussing to what extent Minor Neurocognitive Disorder should be diagnosed in the setting of disorders like schizophrenia and depression. They also realize that issues of this nature are being addressed at the DSM-wide level and are awaiting input of these larger discussions, as well as public input on this issue.

    Alzheimer’s Disease Subtype of Major or Minor Neurocognitive Disorders (DSM-5)

    A. Major: Meets criteria for Major Neurocognitive Disorder, with memory being one of the impaired domains.
    Minor: Meets criteria for Minor Neurognitive Disorder with memory impairment AND there is clear supporting evidence for the Alzheimer etiology (e.g. a positive test for a known mutation in an Alzheimer’s disease associated gene), or with evolving research, documentation based on biomarkers or imaging.
    B. Early and prominent impairment in the Memory domain (rarely, other domains such as visuoconstructive perceptual domain may be prominently affected, but Alzheimer’s disease would not be diagnosed without clear supporting imaging, biomarker or genetic evidence).
    Major:Deficits are observed in at least one other domain, often Executive Ability, and as the disease progresses, in additional domains.
    Minor:Only Memory may be affected, but deficits in Executive Abilities are common.
    C. The course is characterized by gradual onset and continuing cognitive decline
    D. Evidence from history, examination, and investigations that deficits are not wholly or primarily attributable to other disorders. However, other such disorders may coexist.
    RATIONALE FOR CHANGE

    Alzheimer’s disease is a neurodegenerative disorder, typically seen in late life, but can occur earlier. It is marked by insidious onset, gradual decline, and typically an early prominent memory loss. For Major Neurocognitive Disorder this typical clinical picture has excellent predictive value for the Alzheimer subtype and is all that is required for a diagnosis of the Alzheimer subtype, although additional evidence adds to the certainty of diagnosis. For less typical clinical profiles such as posterior coritical atrophy or visual variant of AD, additional supportive evidence such as typical neuroimaging patterns of atrophy is required. For Minor Neurocognitive Disorder, because of the modest predictive value of the clinical picture alone and the significant social consequences of an Alzheimer diagnosis, the Alzheimer’s disease subtype is not commonly diagnosed. However, such a diagnosis is possible if there is sufficient information available (e.g., a positive genetic test for dominantly inherited AD, or as the field develops, evidence that certain imaging markers, atrophy of medial temporal lobe structures on MRI, temporoparietal hypometabolism on FDG PET, amyloid deposition on PET scanning or markers for tau and abeta in the CSF are sufficiently predictive of an underlying AD pathology).
    While patients in memory disorders clinics who meet current research criteria for Mild Cognitive Impairment (similar to Minor Neurocognitive Disorder with impaired memory) progress to dementia of the Alzheimer type at the rate of 12-15% per year and have neuropathological evidence of both neurodegeneration and cerebrovascular disease, population-based studies show a much lower rate of progression with some individuals improving. Research is ongoing into what specific features of MCI might reliably indicate the presence of prodromal Alzheimer’s disease. Until those features can be identified, the Neurocognitive Disorders Work Group does not feel that the predictive value of Minor Neurocognitive Disorder (minor NCD) with memory impairment is sufficient for a diagnosis of Alzheimer’s disease. However, such a diagnosis might be made in an individual with an autosomal dominant family history or positive test for a mutation in an autosomal dominant “AD gene”, or, after further research, with clearly predictive biomarkers or imaging studies.

    • This is an area in which knowledge is evolving rapidly; the procedures described above are increasingly used in clinical practice at tertiary care centers and outside the US. It is possible some of them will enter standard use in the near future.
    • Previous terminology was revised to recognize the clinical and pathological evidence that comorbidity is the norm in the population at large, that having cerebrovascular disease does not preclude also having Alzheimer’s disease and vice versa, and in the presence of both, it is not useful to arbitrarily assign causality to one or the other.
    • There is little scientific rationale for retaining the distinction between early and late onset, as the underlying pathology is the same, and the threshold of age 65 is arbitrary at best.

    Criteria for Psychosis of AD:

    A. Characteristics symptoms: Delusions or auditory or visual hallucinations

    B. Primary diagnosis: AD: Chronology of onset of symptoms of dementia prior to onset of psychotic symptoms

    C. Duration: >1 month, although the delusions and hallucinations may be intermittent; symptoms cause clinically significant distress or functional disruption

    D. Symptoms not exclusively during delirium

    E. Symptoms not due to direct physiological effects of a substance and cannot be better accounted for schizophrenia or other psychotic disorder

    Rationale

    (1) Public health importance: High prevalence & incidence

    (2) Associated with: More agitation, aggression, More rapid cognitive decline, Greater caregiver distress, earlier institutionalization, and higher cost of care

    (3) Persistence or recurrence common

    (4) Aggregates in families

    (5) Clinical differences between AD + Psychosis and both AD without psychosis and Psychosis without AD

    (6) Specific treatment considerations

    Criteria for Depression of AD:

    A. 3 (or more) of 10 listed symptoms under Major Depressive Disorder

    B. Primary diagnosis: AD

    C. Duration: > 2 weeks; Symptoms cause clinically significant distress or functional disruption

    D. Symptoms not exclusively during delirium

    E. Symptoms not due to direct physiological effects of a substance and cannot be better accounted for by another disorder

    Rationale

    (1) Public health importance: High prevalence and incidence

    (2) Associated with: Higher mortality and Higher cost of care

    (3) Persistence or recurrence common

    (4) Clinical differences between AD + depression and both AD without depression and Depression without AD

    (5) Specific treatment considerations

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