Exploring the lived experience: impact of dementia diagnosis on individuals with cognitive impairment - a qualitative study.

OBJECTIVE: Although knowledge about the experience of being diagnosed with dementia is limited, with the expected rise in dementia's prevalence in the coming decades, such knowledge is pivotal for the people diagnosed, their families, and healthcare planners. Thus, the aim of our study was to explore the experience of living with cognitive impairment and dementia and the impact of being diagnosed with dementia. METHOD: A qualitative design was applied. Participants were recruited based on age-adjusted values below ​​threshold values on the Montreal Cognitive Assessment Scale (i.e. 70-79 years, < 22; 80-89 years, < 21; 90 + years, < 20), and the sample ultimately included 15 participants: six with and nine without a documented dementia diagnosis. Qualitative content analysis was performed on the transcribed interviews in four steps to identify codes, categories, and the overall theme. RESULTS: Three major categories emerged from the interviews: (1) experiences with changes, (2) experiences with being diagnosed with dementia, and (3) existential experience. All participants with and most participants without a dementia diagnosis experienced changes in cognition. CONCLUSION: Our findings imply that being diagnosed with dementia is a relief because it explains observed cognitive and functional decreases and reduces confusion, shame and stigma. However, it also raises concerns about an unknown future. Most participants not diagnosed with dementia reported having little or no difficulty with everyday living and leading a fulfilling life. Those findings emphasise the significance of timely versus early diagnosis.

Public knowledge about dementia risk reduction in Norway.

BACKGROUND: Several modifiable lifestyle risk factors for dementia have been identified, but it is unclear how much the Norwegian public knows about the relationship between lifestyle and brain health. Therefore, this study aimed to investigate knowledge about modifiable dementia risk and protective factors and beliefs and attitudes towards dementia and dementia risk reduction in a randomly selected subsample of the Norwegian population. METHODS: The total sample (n = 1435) included individuals aged 40-70 years from four counties (Oslo, Innlandet, Nordland and Trøndelag) in Norway. Two online questionnaires were used to measure (1) awareness about dementia risk reduction and (2) an individual`s motivation to change behaviour for dementia risk reduction (MOCHAD-10). RESULTS: Of the participants, 70% were aware of the potential of dementia risk reduction in general. Physical inactivity (86%), cognitive inactivity (84%) and social isolation (80%) were the most frequently recognised dementia risk factors. On the other hand, diabetes (26%), coronary heart disease (19%), hearing loss (18%) and chronic kidney disease (7%) were less often recognised as dementia risk factors. Comparing men and women, the only significant difference was that women were more likely to report parents with dementia as a risk factor compared to men. Gender, age and educational differences were seen in beliefs and attitudes towards dementia prevention:women reported more negative feelings and attitudes towards dementia than men;those aged 40-49 years - more likely than older age groups - reported that 'knowing family members with dementia' or 'having risk factors' made them believe they had to change their lifestyle and behaviour. CONCLUSIONS: The results indicate that 70% of the Norwegian public are aware of the potential for dementia risk reduction in general. However, there are major gaps in existing knowledge, particularly for cardiovascular risk factors such as hypertension, coronary heart disease, hypercholesterolemia and metabolic factors (diabetes, obesity). These findings underline the importance of further informing the Norwegian public about lifestyle-related risk and protective factors of dementia. Differences in beliefs and attitudes towards dementia risk prevention by age, gender and education require tailored public risk reduction interventions.

Global Study of Social Odor Awareness.

Olfaction plays an important role in human social communication, including multiple domains in which people often rely on their sense of smell in the social context. The importance of the sense of smell and its role can however vary inter-individually and culturally. Despite the growing body of literature on differences in olfactory performance or hedonic preferences across the globe, the aspects of a given culture as well as culturally universal individual differences affecting odor awareness in human social life remain unknown. Here, we conducted a large-scale analysis of data collected from 10 794 participants from 52 study sites from 44 countries all over the world. The aim of our research was to explore the potential individual and country-level correlates of odor awareness in the social context. The results show that the individual characteristics were more strongly related than country-level factors to self-reported odor awareness in different social contexts. A model including individual-level predictors (gender, age, material situation, education, and preferred social distance) provided a relatively good fit to the data, but adding country-level predictors (Human Development Index, population density, and average temperature) did not improve model parameters. Although there were some cross-cultural differences in social odor awareness, the main differentiating role was played by the individual differences. This suggests that people living in different cultures and different climate conditions may still share some similar patterns of odor awareness if they share other individual-level characteristics.

The brain structural and cognitive basis of odor identification deficits in mild cognitive impairment and Alzheimer's disease.

BACKGROUND: The objectives of this study were to explore the relationship between olfactory impairment, cognitive measures, and brain structure volumes in healthy elderly individuals, compared to patients with amnestic mild cognitive impairment (aMCI) or early Alzheimer's disease (AD). The primary aim was to elucidate possible differences in cognitive scores and brain structure volumes between aMCI/AD patients with relatively intact odor identification (OI) ability and those with reduced ability. METHODS: Twelve patients with aMCI, six with early AD, and 30 control subjects were included. OI abilities were assessed with the Brief Smell Identification Test (B-SIT) and Sniffin Sticks Identification Test (SSIT). Neuropsychological tests of executive functions and memory were performed. Brain structural volumes were obtained from T1 weighted 3D MRI at 3 Tesla. Statistical comparisons between the patients with aMCI and AD indicated no significant differences in performance on most tests. Since the groups were small and AD patients were in an early phase of disease, all patients were subsequently considered together as a single group for studying OI. Patients were subdivided into relatively intact (scores >50%) and reduced OI (≤ 50% score) on the olfactory tests. RESULTS: The aMCI/AD group with reduced OI ability, as measured by both B-SIT and SSIT, had significantly smaller hippocampal volume as compared to the patient group with OI scores > 50%. There was a significant association between OI scores and hippocampal volume in the patient (not the control) group. Similar changes with tests of executive function and memory were not found. Low OI scores on B-SIT were associated with conversion from aMCI to AD in patients. The reduced OI patient group was significantly faster on Rey complex figure copying than the fairly intact OI group. CONCLUSION: The results from this pilot study suggest that the reduction in the size of hippocampus in connection with early AD is associated more with loss of OI ability rather than loss of memory, thus demonstrating that impaired OI is an early marker of medial temporal lobe degeneration.

Hippocampal involvement in retrieval of odor vs. object memories.

The aim of this study was to investigate the role of the human hippocampus in episodic retrieval of odors, in comparison with episodic retrieval of visual objects. Subjects encoded a set of unique odors and objects, and retrieval was tested the next day during functional magnetic resonance imaging (fMRI). Subjects were shown the names of old (studied) and new (unstudied) odors and objects, and asked to indicate which of these stimuli had been presented the previous day. The results showed that brain activation was weaker and more restricted during retrieval of odors than during retrieval of objects, which possibly reflects a general visual dominance effect. Yet, retrieval of odors and objects yielded overlapping clusters of activation the bilateral hippocampi, and the left-sided activation was specifically increased during successful retrieval (hits > correct rejections) in both modalities. Moreover, retrieval of odors uniquely activated olfactory cortical regions, likely to reflect cortical reinstatement of sensory details. Our fMRI study is the first to make a direct comparison between olfactory and visual episodic memory, and the results provide clear evidence for modality-independent functions of the hippocampus.

The human brain representation of odor identification.

Odor identification (OI) tests are increasingly used clinically as biomarkers for Alzheimer's disease and schizophrenia. The aim of this study was to directly compare the neuronal correlates to identified odors vs. nonidentified odors. Seventeen females with normal olfactory function underwent a functional magnetic resonance imaging (fMRI) experiment with postscanning assessment of spontaneous uncued OI. An event-related analysis was performed to compare within-subject activity to spontaneously identified vs. nonidentified odors at the whole brain level, and in anatomic and functional regions of interest (ROIs) in the medial temporal lobe (MTL). Parameter estimate values and blood oxygenated level-dependent (BOLD) signal curves for correctly identified and nonidentified odors were derived from functional ROIs in hippocampus, entorhinal, piriform, and orbitofrontal cortices. Number of activated voxels and max parameter estimate values were obtained from anatomic ROIs in the hippocampus and the entorhinal cortex. At the whole brain level the correct OI gave rise to increased activity in the left entorhinal cortex and secondary olfactory structures, including the orbitofrontal cortex. Increased activation was also observed in fusiform, primary visual, and auditory cortices, inferior frontal plus inferior temporal gyri. The anatomic MTL ROI analysis showed increased activation in the left entorhinal cortex, right hippocampus, and posterior parahippocampal gyri in correct OI. In the entorhinal cortex and hippocampus the BOLD signal increased specifically in response to identified odors and decreased for nonidentified odors. In orbitofrontal and piriform cortices both identified and nonidentified odors gave rise to an increased BOLD signal, but the response to identified odors was significantly greater than that for nonidentified odors. These results support a specific role for entorhinal cortex and hippocampus in OI, whereas piriform and orbitofrontal cortices are active in both smelling and OI. Moreover, episodic as well as semantic memory systems appeared to support OI.

The Human Brain Representation of Odor Identification in Amnestic Mild Cognitive Impairment and Alzheimer's Dementia of Mild Degree.

Background: Odor identification (OI) ability is a suggested early biomarker of Alzheimer's disease. In this study, we investigated brain activity within the brain's olfactory network associated with OI in patients with amnestic mild cognitive impairment (aMCI) and mild Alzheimer's dementia (mAD) to uncover the neuronal basis of this impairment. Materials and Methods: Patients with aMCI (n = 11) or mAD (n = 6) and 28 healthy older adults underwent OI functional MRI (fMRI) at 3T, OI, odor discrimination, and cognitive tests and apolipoprotein-e4 (APOE4) genotyping. Eleven patients had cerebrospinal fluid (CSF) analyzed. Those with aMCI were followed for 2 years to examine conversion to dementia. Results: The aMCI/mAD group performed significantly worse on all OI tests and the odor discrimination test compared to controls. The aMCI/mAD group had reduced activation in the right anterior piriform cortex compared to the controls during OI fMRI [Gaussian random field (GRF) corrected cluster threshold, p < 0.05]. This group difference remained after correcting for age, sex education, and brain parenchymal fraction. This difference in piriform activity was driven primarily by differences in odor discrimination ability and to a lesser extent by OI ability. There was no group by odor discrimination/identification score interaction on brain activity. Across both groups, only odor discrimination score was significantly associated with brain activity located to the right piriform cortex. Brain activity during OI was not associated with Mini Mental Status Examination scores. At the group level, the aMCI/mAD group activated only the anterior insula, while the control group had significant activation within all regions of the olfactory network during OI fMRI. There was no association between brain activity during OI fMRI and total beta-amyloid levels in the CSF in the aMCI/mAD group. Conclusion: The OI impairment in aMCI/mAD patients is associated with significantly reduced activity in the piriform cortex compared to controls. Activation of downstream regions within the olfactory network is also significantly affected in the aMCI/mAD group, except the anterior insula, which is impinged late in the course of Alzheimer's disease. OI tests thus reflect Alzheimer's disease pathology in olfactory brain structures.

Use of the Brief Smell Identification Test for olfactory deficit in a Norwegian population with Alzheimer's disease.

AIMS: Several studies have shown that Alzheimer's disease (AD) is associated with hyposmia. Olfactory identification may be a cheap and simple additional test in the assessment of early cognitive changes. The sense of smell is influenced by factors such as experience and culture and the aim of the present study was to assess the validity of the Brief Smell Identification Test (B-SIT) in distinguishing patients with AD from healthy gender and age-matched controls in a Norwegian population. METHODS: The study included 39 patients with a diagnosis of probable AD, and 52 gender and age-matched controls. Olfactory function was assessed with B-SIT, and a non-standardized olfactory identification task (freshly ground coffee). RESULTS: The difference in olfactory performance between patients and controls was highly significant, both for the whole AD patient group and the subgroup of patients with MMSE >or= 24. Receiver operating curve (ROC) analyses indicated that B-SIT distinguished patients from controls with high sensitivity and specificity. All the odours in B-SIT with the exception of turpentine showed highly significant differences between patients and controls. AD-associated memory impairment did not seem to affect the answers given for B-SIT in this population. CONCLUSIONS: For patients with AD, the Brief Smell Identification Test (B-SIT) appears to be well-suited for detecting a deficit in olfactory identification in a Norwegian population.