Deficient Novelty Detection and Encoding in Early Alzheimer's Disease: An ERP Study.

Patients with early Alzheimer's disease (AD) have difficulty in learning new information and in detecting novel stimuli. The underlying physiological mechanisms are not well known. We investigated the electrophysiological correlates of the early (< 400 ms), automatic phase of novelty detection and encoding in AD. We used high-density EEG Queryin patients with early AD and healthy age-matched controls who performed a continuous recognition task (CRT) involving new stimuli (New), thought to provoke novelty detection and encoding, which were then repeated up to 4 consecutive times to produce over-familiarity with the stimuli. Stimuli then reappeared after 9-15 intervening items (N-back) to be re-encoded. AD patients had substantial difficulty in detecting novel stimuli and recognizing repeated ones. Main evoked potential differences between repeated and new stimuli emerged at 180-260 ms: neural source estimations in controls revealed more extended MTL activation for N-back stimuli and anterior temporal lobe activations for New stimuli compared to highly familiar repetitions. In contrast, AD patients exhibited no activation differences between the three stimulus types. In direct comparison, healthy subjects had significantly stronger MTL activation in response to New and N-back stimuli than AD patients. These results point to abnormally weak early MTL activity as a correlate of deficient novelty detection and encoding in early AD.

Internet Use and Problematic Use in Seniors: A Comparative Study in Switzerland and Poland.

Background: Seniors have been only little considered in studies examining problematic internet use and associated health issues, although they may present risk factors that make them particularly vulnerable for the development of problematic internet use. Objectives: (1) To compare Internet use and problematic use among seniors in Switzerland and Poland; (2) To examine the relationships between problematic internet use, impulsivity traits and well-being as previous studies showed that internet can be used to cope with negative emotions or life dissatisfaction. Methods: A cross-sectional survey conducted between June 2016 and April 2017 with 264 older internet users aged above 60 years old recruited in Switzerland (88) and Poland (176) assessing sociodemographic variables, online activities, problematic internet use, impulsivity traits and well-being. Results: The two groups differed in their reported online activities in that Polish participants reported more searching for information and buying, whereas Swiss participants reported significantly greater problematic internet use than Polish participants. Finally, a multiple linear regression analysis performed on the whole sample indicated that lower well-being and being a Swiss participant were both significantly associated with greater problematic internet use, after age, gender, level of education, impulsivity traits have been controlled for. Discussion: Swiss seniors showed a more problematic internet use than Polish participants who focused more in their online activities on utility use of internet. The relationships between problematic internet use and well-being suggest that older adults use internet mainly to cope with negative emotion or life dissatisfaction. Socio-cultural differences that could account for these group differences as well as difference with young adults are discussed.

The A/T/N model applied through imaging biomarkers in a memory clinic.

PURPOSE: The A/T/N model is a research framework proposed to investigate Alzheimer's disease (AD) pathological bases (i.e., amyloidosis A, neurofibrillary tangles T, and neurodegeneration N). The application of this system on clinical populations is still limited. The aim of the study is to evaluate the topography of T distribution by 18F-flortaucipir PET in relation to A and N and to describe the A/T/N status through imaging biomarkers in memory clinic patients. METHODS: Eighty-one patients with subjective and objective cognitive impairment were classified as A+/A- and N+/N- through amyloid PET and structural MRI. Tau deposition was compared across A/N subgroups at voxel level. T status was defined through a global cut point based on A/N subgroups and subjects were categorized following the A/T/N model. RESULTS: A+N+ and A+N- subgroups showed higher tau burden compared to A-N- group, with A+N- showing significant deposition limited to the medial and lateral temporal regions. Global cut point discriminated A+N+ and A+N- from A-N- subjects. On A/T/N classification, 23% of patients showed a negative biomarker profile, 58% fell within the Alzheimer's continuum, and 19% of the sample was characterized by non-AD pathologic change. CONCLUSION: Medial and lateral temporal regions represent a site of significant tau accumulation in A+ subjects and possibly a useful marker of early clinical changes. This is the first study in which the A/T/N model is applied using 18F-flortaucipir PET in a memory clinic population. The majority of patients showed a profile consistent with the Alzheimer's continuum, while a minor percentage showed a profile suggestive of possible other neurodegenerative diseases. These results support the applicability of the A/T/N model in clinical practice.

A systemic literature review of neuroimaging studies in women with breast cancer treated with adjuvant chemotherapy.

Chemotherapy-induced cognitive deficits in patients with breast cancer, predominantly in attention and verbal memory, have been observed in numerous studies. These neuropsychological findings are corroborated by the results of neuroimaging studies. The aim of this paper was to survey the reports on cerebral structural and functional alterations in women with breast cancer treated with chemotherapy (CTx). First, we discuss the host-related and disease-related mechanisms underlying cognitive impairment after CTx. We point out the direct and indirect neurotoxic effect of cytostatics, which may cause: a damage to neurons or glial cells, changes in neurotransmitter levels, deregulation of the immune system and/or cytokine release. Second, we focus on the results of neuroimaging studies on brain structure and function that revealed decreased: density of grey matter, integrity of white matter and volume of multiple brain regions, as well as their lower activation during cognitive task performance. Finally, we concentrate on compensatory mechanisms, which activate additional brain areas or neural connection to reach the premorbid cognitive efficiency.

Verbal fluency in breast cancer patients treated with chemotherapy.

BACKGROUND: Cognitive decline caused by chemotherapy used in the treatment of malignant diseases was reported in several studies. ICCTF recommends the diagnosis of cognitive function in patient treated with chemotherapy. One of the suggested method is Verbal Fluency Test (VFT). METHODS: Study was carried out on a group of 30 women with early breast cancer treated with adjuvant chemotherapy and 29 healthy controls. The patients underwent neuropsychological assessment using VFT at three time points: T1: before chemotherapy, T2: mid-chemotherapy and T3: post-chemotherapy. The examination in healthy controls was conducted at the same time intervals. RESULTS: In phonetic fluency task patients produced more words at T2 compared to T1 (Z = 2.02; p < 0.05) and at T3 compared to T1, both patients (Z = 2.36; p < 0.05) and controls (Z = 2.57; p < 0.01). The patients scored lower than controls (Z = -2.04; p < 0.05) as well as on average cluster size in the same task (Z = -2.38; p < 0.05) at T3, while they scored higher on the number of phonetic switches at T2 compared to T1 (Z = 2.62; p < 0.01) and at T3 compared to T1 (Z = 2.50; p < 0.01). In semantic task controls produced more words at T3 than at T1 (Z = 2.62; p < 0.01) and at T3 compared to T2 (Z = 2.89; p < 0.01) and semantic clusters at T3 compared to T2 (Z = 2.43; p < 0.05). In patients, number of clusters was smaller at T3 compared to T2 (Z = -2.85; p < 0.05), while number of semantic switches was higher at T3 than at T2 (Z = 3.05; p < 0.01). Patients scored also lower than controls on number of semantic switches at T2 (Z = -2.05; p < 0.05). CONCLUSIONS: Chemotherapy does not decrease verbal fluency, but it has a negative impact on semantic memory.