Investigating the relationship between periodontitis and specific memory processes in the search for cognitive markers of Alzheimer's disease risk

The spontaneous retrieval deficit (SRD) hypothesis argues that individuals in the preclinical stages of Alzheimer’s disease (AD) are particularly impaired in spontaneous retrieval, which manifests in reduced mind-wandering. Our main purpose was to provide novel evidence to support the SRD hypothesis by investigating, for the first time, the relationship between mind-wandering and periodontitis, the latter being the risk factor for AD. The second objective was to address the lack of deeper understanding of the relationship between oral health and specific cognitive abilities by investigating whether periodontitis would be primarily associated with memory. Sixty community-dwelling dementia-free older adults completed neuropsychological tests that focused on various cognitive abilities and a computerised task, during which mind-wandering was evaluated. Periodontal health was assessed subjectively, and through an oral examination by a qualified dentist that focused on visible periodontitis-related changes in gingival tissues and the number of periodontitis bacteria. In line with our predictions, objective and subjective symptoms of poorer periodontal health were associated with less mind-wandering, providing further support for the SRD hypothesis. Again in line with predictions, poorer periodontal health was associated with worse episodic memory, with no relationship between periodontitis and the measure targeting various cognitive abilities, from which memory was excluded

An Inquisit-web protocol for calculating composite inhibitory control capacity score : an individual differences approach

In the present paper, we provide a protocol for experimentally measuring and calculating individual inhibitory control capacity index in adult participants in an online Inquisit-based setting. We believe that this method can serve other researchers in the standardized assessment of individual inhibitory control capacity that can be used in studies on the possible role of inhibitory control in many every-day cognitive phenomena. Thus, the paper focuses mainly on the calculation of a composite inhibitory control capacity score from two inhibitory control tasks. Specifically, it is calculated on the basis of participants’ performance in two well-established experimental paradigms: the Stroop Task and the Eriksen Flanker Task. The methods described in this protocol have already been successfully applied in both lab and online settings. In the first part of the article, we provide a short theoretical background and a brief description of the previous usage of this method in our two original studies. In the following parts, we provide step-by-step instructions for measuring and calculating the individual inhibitory control capacity index using web-based methodology. The protocol is supplemented with slides of original experimental tasks and instructions for participants (both translated from Polish)

Prospective memory in older adults with the Subjective Cognitive Impairment

Celem projektu było zbadanie relacji między Subiektywnymi Zaburzeniami Poznawczymi i sprawnością pamięci prospektywnej wśród osób starszych. Jest to niezwykle ważna kwestia, ponieważ obecność subiektywnych skarg na funkcjonowanie pamięci może być potencjalnym markerem wczesnej deterioracji poznawczej wśród starszych osób, a co za tym idzie – przesłanką do wnioskowania o ryzyku wystąpienia chorób neurodegeneracyjnych w przyszłości. Badanie składało się z dwóch części: selekcji osób badanych oraz fazy testowej, podczas której badani wypełniali baterię testów neuropsychologicznych oraz wykonywali zadanie mierzące pamięć prospektywną na urządzeniu elektronicznym. W badaniu założono, że osoby które niżej oceniają swoją pamięć będą osiągały gorsze wyniki w zadaniu prospektywnym. Mimo, że uzyskane dane nie potwierdziły tej hipotezy, to kiedy podzielono uczestników na tych, którzy uzyskali maksimum punktów w zadaniu prospektywnym i tych, którzy wypadli gorzej, okazało się że ta druga grupa oceniła swoją pamięć istotnie niżej niż pierwsza. Otrzymane wyniki rzucają nowe światło na kwestię Subiektywnych Zaburzeń Poznawczych.The aim of the study was to explore the relationship between the Subjective Cognitive Impairment and the efficiency of prospective memory among the older adults. It is the important issue, because the presence of subjective complaints about one’s memory can be a potential marker of early cognitive decline among the elderly, and therefore – the indicator of a risk of neurodegenerative disorders in the future. The study consisted of two parts: the selection of participants and the testing phase, during which the participants completed the battery of neuropsychological tests and the prospective memory task on an electronic device. It was assumed that participants with the lower memory self-evaluation would perform poorer on the prospective memory task. Although the results did not support this hypothesis, when participants were divided into those who obtained a maximum score on the prospective memory task and those who performed worse, the latter group evaluated their memory significantly lower. These results shed a new light on the Subjective Cognitive Impairment

Deficits in spontaneous and stimulus-dependent retrieval as an early sign of abnormal aging

Research on early cognitive markers of Alzheimer’s disease is primarily focused on episodic memory tests that involve deliberate retrieval. Our purpose was to provide clear evidence to support a novel Spontaneous Retrieval Deficit hypothesis, which predicts that people at pre-clinical stages of dementia, including those with amnestic Mild Cognitive Impairment (aMCI), are particularly impaired on tasks based on spontaneous retrieval. We compared 27 aMCI individuals and 27 healthy controls on mind-wandering while performing a task during which there were exposed to either highly meaningful or unmeaningful pictures. The substantial reduction in mind-wandering among individuals with aMCI was found with exposure to highly meaningful stimuli, but not to unmeaningful pictures, and it was most pronounced for past-oriented thoughts, i.e., involuntary autobiographical memories. Those findings provide strong support for this novel hypothesis, and show that it is the spontaneous, but bottom-up and cue-driven processes, for which meaningful environmental stimuli are crucial, that are very promising early markers of the disease

Dementia-free older adults with subjective cognitive impairment show lower mood and no deficits of spontaneous memory retrieval

The aim of the present study was to investigate whether spontaneous retrieval deficits could be found in individuals with Subjective Cognitive Impairment (SCI). The sample consisted of 52 participants over 65 years of age (mean age = 76.00; SD = 7.48) with 11 males. We asked 26 individuals with SCI and 26 individuals without SCI to perform a prospective memory (PM) task that had previously demonstrated spontaneous retrieval deficits in individuals with Mild Cognitive Impairment. The results did not demonstrate the expected differences in a PM task based on spontaneous retrieval [t(50) = −.05; p = .964, d = .01]. However, participants’ mood did predict their subjective memory complaints (β = −.51; p < .001) and their subjective assessment of their future memory performance (r = −.38; p < .01). The findings are in line with numerous studies which have shown that SCI is more related to mood disturbance than to objective cognitive functioning

Visual awareness judgments are sensitive to accuracy feedback in stimulus discrimination tasks

In this study we tested the hypothesis that perceptual awareness judgments are sensitive to accuracy feedback about the previous action. We used a perceptual discrimination task in which participants reported their stimulus awareness. We created two conditions: No-feedback and Feedback (discrimination accuracy feedback was provided at the end of each trial). The results showed that visual awareness judgments are related to the accuracy of current and previous responses. Participants reported lower stimulus awareness for incorrectly versus correctly discriminated stimuli in both conditions; they also reported lower stimulus awareness in trials preceded by incorrect discrimination responses, compared to trials preceded by correct discrimination responses. This difference was significantly stronger in the Feedback condition, in which we also observed post-error slowing for PAS ratings. We discuss the relation between visual awareness and the effects of performance monitoring and interpret the results in the context of current theories of consciousness

Hopkins Verbal Learnig Test : polish adaptation and norms for older adults

The aim of this study was to translate and cross-culturally adapt the Hopkins Verbal Learning Test (HVLT, Brandt, 1991) that measures long-term memory for verbal stimuli. The main reason for adapting HVLT was the need for a simple, fast to administer, and valid instrument with Polish norms that will well serve screening for memory impairment. We examined the convergent validity of the HVLT by relating it to the California Verbal Learning Test (Łojek & Stańczak, 2010) and discriminant validity by relating it to several measures of cognitive abilities (i.e. Rey Complex Figure Test, Trail Making Test, and the Digit Span test of WAIS-PL). We adapted two parallel versions of HVLT for the purpose of longitudinal measurement. The HVLT is particularly useful for screening older adults for Mild Cognitive Impairment and early stages of various types of dementia, we thus created Polish norms for older adults in their seventh, eight, and ninth decades separatel

Cognitive inhibition behavioral tasks in online and laboratory settings : data from Stroop, SART and Eriksen Flanker tasks

The provided dataset represents the performance of adult individuals in three experimental tasks measuring cognitive inhibition: the Stroop task; the SART task and the Eriksen Flanker task. All tasks were initially completed in a web setting (online) by 485 individuals. Additionally, randomly selected participants completed all these tasks one more time (220 participants) or two more times (100 participants) during separate laboratory session(s) offline. The provided dataset contains data both from the offline and online experimental sessions. For the Stroop and Flanker tasks, we have provided data on mean reaction times for correct answers and the percent of correct answers for both congruent and incongruent trials. For the SART task, we have provided data on the number and the percent of commission and omission errors; the mean correct reaction times in "go" trials; the standard deviations of correct reaction times in "go" trials; the coefficients of variability for correct reaction times in "go" trials; the mean reaction times for successful "go" trials proceeding successful "no-go" trials; and the mean reaction times for correct "go" trials proceeding failed "no-go" trials. Data from both laboratory sessions contains information on the age and gender of participants. Additionally, we have provided the dates and hours of all experimental sessions. This dataset can potentially be reused for exploratory research on cognitive inhibition, i.e., the stability of individual cognitive inhibition capacity over time; intercorrelations of various inhibition task performance measures; individual differences in cognitive inhibition; or the influence of task setting (web vs laboratory) on inhibition performance measured in different settings (web vs laboratory)

Application of biogas to supply the high compression ratio engine

The study concerns the use of biogas as a fuel for supplying a modified self-ignition engine. As a result of the modifications made, the compression ratio was reduced and the engine was equipped with an ignition system and an electronically activated engine throttle. The changes have made it possible to burn biogas in a high compression ratio engine. The paper presents the results of research conducted on a low power cogeneration system with engine that drives an electrical machine cooperating with a 380/400 V network. The analysis includes, among other things, the possibility of producing electricity using biogas. The paper presents the influence of regulatory parameters such as the volume and composition of the supplied gas mixture and the degree of throttle opening on the obtained engine operation indicators and the driven electric machine. The tests were carried out in relation to the obtained ecological indicators depending on the concentration in the exhaust of such substances as: HC, CO, NOx