Notes - Angela Roberts PDF

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Angela Roberts...

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Introduction Aging – chronological definition is commonly used, but contested  65+ = elderly/older persons  80+ = oldest-old  Brain changes seen in younger group are different from those seen in older group  Person who is slightly obese at age 80 will have a better health outcome than obese person at 65  “Old” is an individual-, culture-, country-, and gender-specific term World population = 7.4 billion  2006: 500M people were 65+ (7%)  2030: projected trend is 1 billion (1 in 8 people) The older population is the fastest growing group worldwide – and we will need to provide services to them Older people (65+) will outnumber young children (1 cognitive domain is invariably involved and substantial interference with daily life is evident  Diagnosis of MCI and mild dementia is based on history and cognitive examination  Prognosis is an important motivation for diagnosis because in both, there is a heightened risk for further cognitive decline  Etiology of MCI and mild dementia can often be established through clinical examination, although imaging and other laboratory tests may also contribute  Although AD is the most common cause of both, CVD and LBD make important contributions  Pharmacological treatments are of modest value in mild dementia due to AD, and there are no approved pharmacological treatments for MCI

How was connected language sample elicited in the Mueller et al. (2016) paper? What measures of language were examined? How did individuals with pMCI differ from cognitively normal controls? The connected language utilized in Mueller et al.’s 2016 paper was elicited by having participants describe the Cookie Theft paper, which comes from the Boston Diagnostic Aphasia Examination and is a detailed black-and-white image featuring several elements that participants should mention while describing it. Language samples were analyzed for content by measuring total semantic units, semantic unit idea density, propositional idea density, number of unique and total words, proportion of pronouns, proportion of verbs, and moving 18

average type-token ratio (MATTR), which is a measure of lexical diversity. The samples were also analyzed for syntactic complexity by measuring mean length of utterance (MLU) and verb index, which is a ratio of total verbs to total number of utterances. Lastly, speech fluency was evaluated by analyzing participants’ maze index, which is a measure of repetitions, revisions, false starts, and filler words in speech, and participants’ filled pauses, which was the proportion of filler words to total number of utterances. Individuals with pMCI performed significantly poorer on measures of content, in that they produced fewer semantic units, fewer unique words, and displayed smaller idea density, than cognitively normal controls. Idea density was defined as the number of semantic units divided by the total number of words. In addition, participants in the the pMCI group performed worse on phonemic and semantic fluency tasks that the authors administered alongside the language sample. This indicates semantic language differences in patients with pMCI compared to cognitively normal controls. Semantic memory declines may reflect the underlying early neuropathology of MCI, so tasks such as this language sample could offer a quick, noninvasive way to assess for possible cognitive decline. Mueller et al (2016)  Connected language is often impaired among people with AD, yet little is known about when language difficulties first emerge on the path to a diagnosis  Objective = determine whether individuals with psychometric (preclinical) evidence of amnestic Mild Cognitive Impairment (MCI) (pMCI) showed deficits in connected language measures.  Participants = 39 pMCI and 39 cognitively healthy (CH) adults  Methods = participants described Cookie Theft picture from BDAE o Language samples were analyzed across 3 language domains: content, syntactic complexity, and speech fluency  Results o CH and pMCI groups differed significantly on measures of content (e.g., CH group produced more semantic units, more unique words and had larger idea density, on average, than the pMCI group) o Findings are consistent with previous retrospective studies showing semantic language differences in adults with autopsy-confirmed AD  Findings may represent subtle language difficulty in spontaneous speech, and may be predictive of larger language changes over time. Wierenga (2011): What we know how about dementia and AD Sachdev et al (2015)  Neurocognitive disorders—including delirium, MCI and dementia—are characterized by decline from a previously attained level of cognitive functioning  Diverse clinical characteristics and aetiologies, with AD, CVD, LBD, FTD, TBI, infections, and alcohol abuse representing common causes o Diversity is reflected by the variety of approaches to classifying these disorders, with separate groups determining criteria for each disorder on the basis of aetiology o There is an array of terms to describe cognitive syndromes, various definitions for the same syndrome, and often multiple criteria to determine a specific aetiology

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DSM-5 provides a common framework for diagnosis of neurocognitive disorders, first by describing the main cognitive syndromes, and then defining criteria to delineate specific aetiological subtypes of mild and major neurocognitive disorders o Builds on the expectation that clinicians and research groups will welcome a common language to deal with neurocognitive disorders o As use of these criteria becomes widespread, a common international classification for these disorders could emerge, promoting communication among clinicians and researchers.

McKhann et al (2011)  National Institute on Aging and the Alzheimer’s Association charged a workgroup with the task of revising the 1984 criteria for Alzheimer’s disease (AD) dementia o Workgroup sought to ensure that revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsych testing, advanced imaging, and CSD measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available  New criteria for all-cause dementia and for AD dementia o Retained the general framework of probable AD dementia from 1984 criteria, but made several changes in the clinical criteria for the diagnosis o Retained the term possible AD dementia, but redefined it in a manner more focused than before  Biomarker evidence was integrated into diagnostic formulations for probable and possible AD dementia for use in research settings o Core clinical criteria will continue to be the cornerstone of diagnosis in clinical practice o Biomarker evidence will enhance pathophysiological specificity of diagnosis of AD dementia o Much work lies ahead for validating biomarker diagnosis of AD dementia Weintraub et al (2012)  Neuropsychological assessment has featured prominently over the past 30 years in the characterization of dementia associated with AD  Clinical neuropsych methods have identified the earliest, most definitive cognitive and behavioral symptoms of illness, contributing to the identification, staging, and tracking of disease  With increasing public awareness of dementia, disease detection has moved to earlier stages of illness, at a time when deficits are both behaviorally and pathologically selective  Early AD pathology frequently targets large-scale neuroanatomical networks for episodic memory before other networks that subserve language, attention, executive functions, and visuospatial abilities  Reviews pathognomonic neuropsychological features of AD dementia and how these differ from “normal,” age-related cognitive decline, and from other neurodegenerative diseases that cause dementia (cortical LBD, FTD, and CVD)

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