What is dementia? 6. From physiological aging to dementia

Many studies have been devoted to the cognitive changes associated with age, and several attempts have been made for their classification in order to distinguish normal from pathologic changes. In the last few years, a consensus has been reached to classify elderly people in three groups: a) cognitively normal subjects whose cognitive functions score in the range of those of healthy subjects paired according to age and educational level, presenting or not memory complaints; b) subjects with dementia; c) an intermediate group of subjects presenting a cognitive impairment not severe enough to meet the criteria for dementia. The term mild cognitive impairment (MCI) has been proposed to describe these subjects who are at high risk to progress to dementia in the years following the diagnosis. For the first time, MCI construct allows the recognition of the prementia phase of degenerative or vascular cerebral diseases progressing to dementia. However, the lack of clear operational diagnostic criteria and ambiguities about the signification of MCI make the interpretation of the results of studies devoted to this concept hazardous. From a practical point of view, the physician, when faced with a patient complaining of his\her memory, should answer two main questions. "How to recognize memory disorders resulting from incipient AD?" and "What is the signification of memory complaints not related to AD?" The semioloy of memory complaints and the qualitative aspects of the memory deficit allow the diagnosis of incipient AD with pretty good accuracy. Due to the location of the first lesions of AD in hippocampal regions, memory disturbances in AD are related to a deficit in memorization of new information in episodic memory. Conversely, memory disorders related to normal aging, depression, and degenerative or vascular brain lesions not involving hippocampus, are related to deficits in the processes of recall of previously memorized informations. Benign memory complaints have been considered to be linked to the decrease of memory performance, and defining a special group of normal elderly subjects. However, no direct relationship has been demonstrated between memory complaints and performance. In our opinion, all memory complaints are essentially related to psychoaffective disturbances, mainly anxiety, changes in identity and decrease of self-esteem associated with aging.     

Is chemotherapy associated with cognitive impairment?

Cancer survivors often report difficulties with memory and concentration—sometimes referred to by patients as "chemobrain" or "chemofog". The results from two recent studies suggest that, while chemotherapy itself may not be associated with cognitive impairment, some patients might already be experiencing cognitive difficulties before treatment is even started.     

Is depression a risk factor for dementia or cognitive decline? A review

BACKGROUND: It is generally accepted that depression can be associated with significant cognitive deficits and that depression can be comorbid with dementia. OBJECTIVE: This review seeks to go further and ask whether depression earlier in life can be a risk factor for subsequent dementia or for cognitive decline. METHODS: A review was made of the epidemiological evidence from case-control and prospective studies that depression is a risk factor. The literature was also reviewed in relation to six hypotheses that might explain an association: (1) depression treatments are a risk factor for dementia, (2) dementia and depression share common risk factors, (3) depression is a prodrome of dementia, (4) depression is an early reaction to cognitive decline, (5) depression affects the threshold for manifesting dementia, and (6) depression is a causal factor in dementia. RESULTS: A meta-analysis found that depression was associated with an increased risk of subsequent dementia in both case-control studies (95% CI for relative risk: 1.16-3.50) and prospective studies (95% CI: 1.08-3.20). There was little support for hypotheses 1 and 2. The other hypotheses have limited support, but warrant further research. CONCLUSION: There is sufficient evidence to take seriously the possibility that depression is a risk factor for dementia and cognitive decline. Further work is needed to examine depression as a prodrome of vascular dementia, depression as an early reaction to perceived cognitive decline, the effects of depression on the threshold for manifesting dementia, and depression as a source of hippocampal damage through a glucocorticoid cascade.     

It's all about cognitive trajectory: Accuracy of the cognitive charts–MoCA in normal aging,MCI, and dementia

Background

The Montreal Cognitive Assessment (MoCA) is an established cognitive screening tool in older adults. It remains unclear, however, how to interpret its scores over time and distinguish age-associated cognitive decline (AACD) from early neurodegeneration. We aimed to create cognitive charts using the MoCA for longitudinal evaluation of AACD in clinical practice.

Methods

We analyzed data from the National Alzheimer's Coordinating Center (9684 participants aged 60 years or older) who completed the MoCA at baseline. We developed a linear regression model for the MoCA score as a function of age and education. Based on this model, we generated the Cognitive Charts-MoCA designed to optimize accuracy for distinguishing participants with MCI and dementia from healthy controls. We validated our model using two separate data sets.

Results

For longitudinal evaluation of the Cognitive Charts-MoCA, sensitivity (SE) was 89%, 95% confidence interval (CI): [86%, 92%] and specificity (SP) 79%, 95% CI: [77%, 81%], hence showing better performance than fixed cutoffs of MoCA (SE 82%, 95% CI: [79%, 85%], SP 68%, 95% CI: [67%, 70%]). For current cognitive status or baseline measurement, the Cognitive Charts-MoCA had a SE of 81%, 95% CI: [79%, 82%], SP of 84%, 95% CI: [83%, 85%] in distinguishing healthy controls from mild cognitive impairment or dementia. Results in two additional validation samples were comparable.

Conclusions

The Cognitive Charts-MoCA showed high validity and diagnostic accuracy for determining whether older individuals show abnormal performance on serial MoCAs. This innovative model allows longitudinal cognitive evaluation and enables prompt initiation of investigation and treatment when appropriate.     

Mild cognitive impairment. When is it a precursor to Alzheimer's disease?

There is good evidence suggesting that onset of Alzheimer's disease is commonly preceded by an interim phase known as mild cognitive impairment (MCI). Persons who experience this condition are at increased risk for the development of Alzheimer's disease. Diagnosing MCI involves excluding other morbidities and determining whether the patient meets predefined assessment criteria. There is no treatment for the prevention of MCI, but an understanding of the condition can improve patient management. Several clinical trials are underway to investigate potential potential MCI agents.     

What is dementia? 4. Dementia and law

Dementia is a basic point of French civil and criminal law. It justifies the supervision or guardianship of demented subjects and the cancelation of judicial documents. It constitutes a cause of non-responsability in criminal law but the patient with dementia is required to compensate the financial and moral damage of his(her) deeds. However, in the past few years, the term of dementia has been withdrawn from the law and replaced by notions such as mental disorder, thought disturbances... The reason for this modification is that dementia is no more considered as a general condition but as a specific mental disorder. Moreover, new legal concepts result in a better distinction between the mental disorder and its consequences on the behavior of the patient, hence a better adjustment for judicial problem solving. Nevertheless, the term of dementia remains still commonly used in case law on account of its emotive power. Due to this persistent use, should we doubt that dementia is... a disease?     

Swallow respiratory patterns and aging: presbyphagia or dysphagia?

BACKGROUND: Assessment referrals are increasing for unexpected dysphagia, particularly for older people. It is unclear if this is due to more impaired swallows or healthy age-related changes. Swallow respiration coordination prevents aspiration, and may deteriorate with age. Nonpathological features of the swallow in healthy aging and the factors that influence an individual's ability to eat and drink safely need greater understanding. Some changes might predispose an older person to dysphagic complications in the event of an insult such as a stroke. We investigated the effects of healthy aging on resting and swallow respiratory patterns. METHODS: Fifty healthy volunteers (aged 20-78 years) were recruited to have swallow respiration patterns recorded on a computer. Bolus volume and consistency variations were studied: 5 and 20 ml of water and 5 ml of yogurt. RESULTS: Measurable swallows significantly decreased with age for water boluses. Swallow apnea increased with age (5 ml of water r = 0.433, p = .002; 5 ml of yogurt r = 0.367, p = .023). Independent of age were: breathing out (occurred after 98% of boluses); multiple swallowing (occurred with all bolus types); post-swallow respiration reset pattern (more irregular after yogurt, Wilcoxon signed rank Z = -2.236, p = .025); and resting respiration. CONCLUSIONS: Subtle changes occur in swallow respiration coordination with age. These changes may be compensatory protective mechanisms rather than the result of decreased muscle mobility or reaction times, and not indicative of impairment. Misattributing healthy age-related changes to impairment affects patient care and the use of healthcare resources.     

Which symptoms can distinguish between subjective cognitive impairment (SCI) and mild cognitive impairment (MCI)?

The SCI, the MCI, and the Alzheimer's disease (AD) are on a spectrum of disease progression; therefore, identification of the earliest signs of cognitive deterioration is becoming a crucial issue. The goal of this study was to examine symptom characteristics and distinguish predictive symptoms in patients with MCI compared with SCI, using caregiver questionnaires. We assessed the Korean Dementia Screening Questionnaire (KDSQ) and Seoul Instrumental activities of Daily Living (S-IADL) of 344 subjects with SCI and 697 with MCI. Multivariate logistic regression analyses were conducted after adjusting for age, sex, and educational status. Common and rare symptoms were similar between the SCI and MCI groups. The most distinguishing features of KDSQ were 'Finds it hard to go somewhere on his/her own using public transportation' (odds ratio=OR=4.56, p<0.0001), 'Has difficulty in operating appliances' (OR=2.47, p=0.001), and 'Keeps repeating the same question' (OR=2.03, p<0.0001). In S-IADL, the most outstanding features were 'using household appliances' (OR=3.99, p<0.0001), 'taking medication' (OR=2.38, p=0.01), and 'using public transportation' (OR=1.94, p=0.04). The dysfunction in 'using household appliance' and 'using public transportation' reflect the possibility of MCI rather than SCI. Therefore, it is suggested that these symptoms also have a discriminative and predictive power in identifying SCI.     

Mild cognitive impairment: what's in a name?

BACKGROUND: Nowadays the term mild cognitive impairment (MCI) is used to fill the gap between cognitive changes associated with normal ageing and those associated with dementia. Despite some agreement in general definitions, MCI is still a heterogeneous clinical syndrome for which no DSM-IV criteria have yet been established. Criteria by Petersen et al. are presently the most applied in clinical practice. Moreover, little attention has been paid to the specific relation between MCI and depression. OBJECTIVE: This review highlights some concerns about the concept of MCI and provides guidelines within the field of neuropsychology to solve them. In a second part, the paper focuses on the specific relationship between depression in the elderly and MCI. RESULTS: We hypothesize that certain test instruments can be used to operationalize the criteria proposed by Petersen et al. Moreover, we suggest that cued recall might be of help to differentiate between progressive and non-progressive MCI. Concerning the specific relation between depression and MCI, we assume that elderly depression with concomitant cognitive problems can be seen as an MCI. CONCLUSION: The proposed adjustments and additions (neuropsychological instruments and the incorporation of depressive symptoms) in the diagnostic flowchart of Petersen may serve as useful tools for clinicians when making a diagnosis of MCI.