Learning From Mistakes: Cognitive and Metabolic Correlates of Errors on Picture Naming in the Alzheimer's Disease Spectrum.

BACKGROUND: Analysis of subtypes of picture naming errors produced by patients with Alzheimer's disease (AD) have seldom been investigated yet may clarify the cognitive and neural underpinnings of naming in the AD spectrum. OBJECTIVE: To elucidate the neurocognitive bases of picture naming in AD through a qualitative analysis of errors. METHODS: Over 1000 naming errors produced by 70 patients with amnestic, visuospatial, linguistic, or frontal AD were correlated with general cognitive tests and with distribution of hypometabolism on FDG-PET. RESULTS: Principal component analysis identified 1) a Visual processing factor clustering visuospatial tests and unrecognized stimuli, pure visual errors and visual-semantic errors, associated with right parieto-occipital hypometabolism; 2) a Concept-Lemma factor grouping language tests and anomias, circumlocutions, superordinates, and coordinates, correlated with left basal temporal hypometabolism; 3) a Lemma-Phonology factor including the digit span and phonological errors, linked with left temporo-parietal hypometabolism. Regression of brain metabolism on individual errors showed that errors due to impairment of basic and higher-order processing of object visual attributes, or of their interaction with semantics, were related with bilateral occipital and left occipito-temporal dysfunction. Omissions and superordinates were linked to degradation of broad and basic concepts in the left basal temporal cortex. Semantic-lexical errors derived from faulty semantically- and phonologically-driven lexical retrieval in the left superior and middle temporal gyri. Generation of nonwords was underpinned by impairment of phonology within the left inferior parietal cortex. CONCLUSION: Analysis of individual naming errors allowed to outline a comprehensive anatomo-functional model of picture naming in classical and atypical AD.

Being the Family Caregiver of a Patient With Dementia During the Coronavirus Disease 2019 Lockdown.

Background: Family caregivers of patients with dementia are at high risk of stress and burden, and quarantine due to the coronavirus disease 2019 (COVID-19) pandemic may have increased the risk of psychological disturbances in this population. The current study was carried out during the national lockdown declared in March 2020 by the Italian government as a containment measure of the first wave of the coronavirus pandemic and is the first nationwide survey on the impact of COVID-19 lockdown on the mental health of dementia informal caregivers. Methods: Eighty-seven dementia centers evenly distributed on the Italian territory enrolled 4,710 caregiver-patient pairs. Caregivers underwent a telephone interview assessing classical symptoms of caregiver stress and concern for the consequences of COVID-19 infection on patient's health. We calculated prevalence of symptoms and regressed them on various potential stress risk factors: caregivers' sociodemographic characteristics and lifestyle, patients' clinical features, and lockdown-related elements, like discontinuity in medical care. Results: Approximately 90% of caregivers reported at least one symptom of stress, and nearly 30% reported four or more symptoms. The most prevalent symptoms were concern for consequences of COVID-19 on patient's health (75%) and anxiety (46%). The main risk factors for stress were identified as a conflicting relationship with the patient and discontinuity in assistance, but caregiver's female sex, younger age, lower education, and cohabitation with the patient also had an impact. Availability of help from institutions or private individuals showed a protective effect against sense of abandonment but a detrimental effect on concern about the risk for the patient to contract COVID-19. The only protective factor was mild dementia severity, which was associated with a lower risk of feeling isolated and abandoned; type of dementia, on the other hand, did not affect stress risk. Conclusion: Our results demonstrate the large prevalence of stress in family caregivers of patients with dementia during the COVID-19 pandemic and have identified both caregivers and situations at a higher risk of stress, which should be taken into account in the planning of interventions in support of quarantined families and patients.

The applause sign in cortical and cortical-subcortical dementia.

The "applause sign" is a motor perseveration described in focal and neurodegenerative disorders and characterized by fronto-subcortical dysfunction. Most previous formal investigations focused on Parkinson's disease or progressive supranuclear palsy. We assessed the prevalence of the applause sign in patients affected by Alzheimer's disease (AD), Lewy body dementia (LBD), corticobasal syndrome (CBS), and posterior cortical atrophy (PCA), with the aim to verify its contribution to the differential diagnosis. We enrolled 20 patients with AD, 20 with LBD, 16 with CBS, and ten with PCA, and 30 healthy controls. The three clap test (TCT) was used to elicit the applause sign, and was scored by raters blinded to the diagnosis. Correlation with motor (extrapyramidal) and cognitive measures was also performed. A maximum 40 % prevalence of a positive applause sign was found in the two parkinsonian syndromes, which could be discriminated from the two cortical groups with a positive predictive value of 82 % and a negative predictive value of 55 %. According to our findings, a diagnosis of LBD or CBS, rather than of AD or PCA, is highly probable in the presence of an abnormal TCP, but cannot be ruled out based on a negative result. No relevant correlates emerged that could clarify the origin and nature of the applause sign.