Cognitive Vergence Recorded with a Webcam-Based Eye-Tracker during an Oddball Task in an Elderly Population

The aim of the present study was to investigate the role of beta oscillatory responses upon cognitive load in healthy subjects and in subjects with mild cognitive impairment (MCI). The role of beta oscillations upon cognitive stimulation is least studied in comparison to other frequency bands. The study included 17 consecutive patients with MCI (mean age = 70.8 ± 5.6 years) according to Petersen's criteria, and 17 age- and education-matched normal elderly controls (mean age = 68.5 ± 5.5 years). The experiments used a visual oddball paradigm. EEG was recorded at 30 cortical locations. EEG-evoked power, inter-trial phase synchronization, and event-related beta responses filtered in 15–20 Hz were obtained in response to target and non-target stimuli for both groups of subjects. In healthy subjects, EEG-evoked beta power, inter-trial phase synchronization of beta responses and event-related filtered beta responses were significantly higher in responses to target than non-target stimuli (p < 0.05). In MCI patients, there were no differences in evoked beta power between target and non-target stimuli. Furthermore, upon presentation of visual oddball paradigm, occipital electrodes depict higher beta response in comparison to other electrode sites. The increased beta response upon presentation of target stimuli in healthy subjects implies that beta oscillations could shift the system to an attention state, and had important function in cognitive activity. This may, in future, open the way to consider beta activity as an important operator in brain cognitive processes.

This study aimed to evaluate P300 as an electrophysiological marker of cognitive function in patients with systemic lupus erythematosus (SLE) who had previous neuropsychiatric (NPSLE) involvement and were diagnosed to have cognitive impairment by standard neuropsychological tests. Event-related potentials (ERPs) were assessed by the auditory and visual oddball paradigms. Amplitude and latency of P300 at the frontal (Fz), central (Cz), and parietal (Pz) regions were determined and compared with controls. P300 detection was performed in NPSLE patients with pre-diagnosed cognitive impairment (n = 9), matched SLE patients without previous NPSLE (non-NPSLE) (n = 9), and healthy controls (n = 15). Auditory oddball task did not show any P300 abnormality between groups. Visual oddball task revealed reduced amplitude of P300 over Fz ( P = .002) and Cz ( P = .009) electrodes in NPSLE patients compared with healthy controls and among those who had predominant memory deficit ( P = .01 at Fz). Abnormal P300 was also observed in non-NPSLE patients at Fz and Cz. Using visual oddball paradigm, abnormal P300 was found in NPSLE patients over frontal and parietal regions compared with normal controls but was not discriminative from possible subclinical disease in non-NPSLE patients. In conclusion, visual oddball paradigm was a more sensitive electrophysiological marker than auditory oddball paradigm for cognitive impairment in NPSLE patients.

BackgroundParkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB) are characterized by intracellular Lewy bodies in the brain neurons and clinical symptoms including cognitive impairment and flucations, motor symptoms, and hallucinations with some differences, namely non‐motor symptoms appear earlier in DLB over PDD patients (McKeith et al., 2017). An unmet need in the actual diagnostic criteria is the availability of biomarkers probing working brain cognitive systems. A promising biomarker may be derived from the frequency analysis of electroencephalographic oscillatory responses (EROs) during cognitive demands, as a decrease of frontal‐central EROs at theta (4‐7 Hz) frequencies was reapatedly demonstrated in Alzheimer’s disease patients with mild cognitive impairment and dementia over cognitively unimpaired (CU) persons (Yener et al., 2007; Guntekin et al., 2008). In this line, the present study tested the hypothesis of abnormal event‐related EROs at theta frequencies in PDD and DLB patients.MethodElectroencephalographic activity was recorded during a visual oddball paradigm (i.e., 30% of target stimuli requiring mental counting intermingled with 70% of stimuli to be ignored) in 15 PDD, 12 DLB, and 15 CU persons. EROs at theta power and phase‐locking were computed for the oddball target stimuli and compared among the groups (ANOVA, p &lt; 0.05).ResultAs compared to the CU group, both PDD and DLB groups showed a strong topographically widespread reduction in ERO theta power (p &lt; 0.005) (Figure 1). They also showed a strong reduction in ERO theta phase‐locking, especially in frontal‐central locations (p &lt; 0.0001)( Figure 2).ConclusionThe present study showed that ERO theta power and phase‐locking during a standard visual oddball paradigm probing visual focused attention and short‐term memory may be suitable biomarkers to investigate working cognitive brain systems in both PDD and LBD patients.

Event-related beta responses of healthy individuals and individuals with mild cognitive impairment during a visual oddball paradigm

The purpose of this study was to assess properties of vergence and saccade eye movements as well as posture in quiet stance, and the effects of thin plantar inserts upon postural and oculomotor control. The performances of 36 young healthy subjects were recorded by a force platform and an eye tracker in three testing conditions: without plantar stimulation, with a 3 millimetre-thick plantar insert, either a Medial or a Lateral Arch Support (MAS / LAS). The results showed a decrease of the Surface and Variance of Speed and a more posterior position of the CoP with either stimulation compared with the control condition. The fractal analysis showed a decrease with MAS. Wavelet analysis in the time-frequency domain revealed an increase in the Cancelling Time of the low frequency band with MAS. These results suggest a better stability for a lower energy cost. Concerning eye movements, the inserts influenced only vergence (not saccades): MAS caused an increase of the phasic amplitude of divergence, and conversely a decrease of the tonic amplitude. In contrast, LAS caused an increase of the tonic amplitude of convergence. Thus, MAS renders divergence less visually driven, while LAS renders convergence more visually driven. We conclude that the CNS uses the podal signal for both postural and vergence control via specific mechanisms. Plantar inserts have an influence upon posture and vergence movements in a different way according to the part of the foot sole being stimulated. These results can be useful to clinicians interested in foot or eye.

Early diagnosis of mild cognitive impairment and Alzheimer's disease using multimodal feature-based deep learning models in a Chinese elderly population.

There are no published data on Mild Cognitive Impairment (MCI) incidence in people over 65years of age in Greece, relevant literature is scarce for Southern Europe, and reported rates worldwide show great variability. To investigate the incidence and risk factors of MCI and its subtypes in the elderly population in Greece. The incidence cohort of the HELIAD study (Hellenic Epidemiological Longitudinal Investigation of Aging and Diet) comprised 955 individuals who received full neurological and neuropsychological evaluation on two separate occasions about three years apart. The MCI incidence rate in our cohort is 54.07 new cases per 1000 person-years, standardized by age and sex to 59.99. Each additional year of age over 65 raises the probability of novel MCI by 6.2%, while lower educational attainment more than doubles the risk for incident MCI. Apolipoprotein E-ε4 (APOE-ε4) carriage results in increased risk for MCI by more than 1.7 times. Incidence rates for amnestic MCI are slightly higher than for the non-amnestic subtype, and AD is the most common potential underlying etiology. The MCI incidence rate in the Greek population over 65years of age is 54/1000 person-years. Advanced age and APOE-ε4 carriage are predisposing factors, while higher educational attainment was found to exert a protective effect. MCI incidence in people over 65years-old in Greece is consistent with reported rates around the world. Larger studies encompassing neuroimaging and cerebrospinal fluid biomarkers will hopefully shed more light on MCI epidemiology in Greece in the future.

Auditory and visual oddball stimulus processing deficits in clinical high risk for psychosis: Forecasting psychosis risk with N200 and P300.

Early sensory information processes are enhanced on visual oddball and S1–S2 tasks in Parkinson's disease: a visual event-related potentials study

Objective To investigate the therapeutic effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on the mild cognitive impairment (MCI). Methods The study recruited 36 volunteers from Shijiazhuang City, who were diagnosed with MCI, and randomly divided into a treatment group (18) and a control group (18). Magnetic stimulation site was located in the dorsolateral prefrontal cortex with the frequency of 20 Hz, and 30 minutes (15 minutes on each side) each time, 5 times a week for 8 weeks. The control group received the same frequency with pseudo-stimulating coil, which produced vibration and sound, but didn′t generate a magnetic field.The MMSE was used to measure cognitive functioning, and event-related potentials (ERPs) in Fz, Cz and Pz were recorded using auditory oddball paradigm. Results (1) Compared with the control group, the patients′ count error rate in the experimental group was reduced after the intervention （F(1,31)=10.335, P 0.05). Conclusion The 8-week high-frequency repetitive transcranial magnetic stimulation treatment may improve the cognitive function in patients with MCI. Key words: Evoked potentials; Repetitive transcranial magnetic stimulation; Mild cognitive impairment

INDIVIDUAL DIFFERENCES IN LIFELONG ABILITIES MUST BE CONSIDERED FOR STAGING OF EARLY AD

To understand the prevalence of older people with mild cognitive impairment (MCI) in Zhejiang province and to provide the basis for elderly early detection and diagnosis of Alzheimer's disease (AD). 1211 more than 60-year-old elderly populations were selected in Zhejiang province, and were given screening questionnaire by general information, the montreal cognitive assessment (MoCA) and mini-mental state examination (MMSE). MCI prevalence of elderly populations in Zhejiang was 20.7% and the AD prevalence was 4.5%. The patient's gender, age, education level, nature of work, sleep status, marital status, whether or not participating in physical exercise, having smoking and drinking habits, whether combined with hypertension and diabetes for MCI prevalence of the elderly were statistically significant (P < 0.05). We should pay attention to take appropriate measures in preventing the cognitive decline for populations as elderly, especially for women, senior, no spouse, engaged in manual labor, low education level, poor quality of sleep and no physical exercise, with smoking and drinking, combined with hypertension and diabetes.

BackgroundWe used an automated Event Related Potentials (ERP) technique to compare ERP responses in amyloid positive and negative group of 75 patients with Mild Cognitive Impairment (MCI) and Dementia in a general neurological outpatient clinic. Over the years, research labs have repeatedly reported abnormal ERP markers in patients with MCI and dementia. Recent advances in technology have made ERP testing safe, easy to use and low cost, thus rendering it suitable for clinical use. Indeed, ERPs have become more routinely used in clinical assessment of neurological patients with cognitive changes. The possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.MethodPatients with a history of cognitive complains underwent an auditory oddball ERP paradigm in conjunction with routine neurological evaluation and imaging studies. Standard neuropsychological testing were available in most cases. Amyloid PET imaging was done as part of the IDEAS (Imaging Dementia ‐Evidence for Amyloid Scanning) study and provided the readings for amyloid load. ERP responses were analyzed in the context of beta amyloid readings, and in relation to the patients’ degree of cognitive deficits.ResultFinal data analysis will be presented at the time of the conferenceConclusionThe possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers. possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.

Extensive research has demonstrated that eye-tracking tasks can effectively indicate cognitive impairment. For example, lab-based eye-tracking tasks, such as the antisaccade task, have robustly distinguished between people with Alzheimer’s disease (AD) and healthy older adults. Due to the neurodegeneration associated with AD, people with AD often display extended saccade latencies and increased error rates on eye-tracking tasks. Although the effectiveness of using eye tracking to identify cognitive impairment appears promising, research considering the utility of eye tracking during naturalistic tasks, such as reading, in identifying cognitive impairment is limited. The current review identified 39 articles assessing eye-tracking distinctions between people with AD, mild cognitive impairment (MCI), and healthy controls when completing naturalistic task (reading, real-life simulations, static image search) or a goal-directed task involving naturalistic stimuli. The results revealed that naturalistic tasks show promising biomarkers and distinctions between healthy older adults and AD participants, and therefore show potential to be used for diagnostic and monitoring purposes. However, only twelve articles included MCI participants and assessed the sensitivity of measures to detect cognitive impairment in preclinical stages. In addition, the review revealed inconsistencies within the literature, particularly when assessing reading tasks. We urge researchers to expand on the current literature in this area and strive to assess the robustness and sensitivity of eye-tracking measures in both AD and MCI populations on naturalistic tasks.

Alzheimer's disease (AD) is the leading cause of Dementia, and mild cognitive impairment (MCI) is often considered a precursor to the development of AD dementia and other types of Dementia. Biomarkers such as amyloid beta are specific and sensitive in identifying AD and can identify individuals who have biological evidence of the disease but have no symptoms, but clinicians and researchers may not easily use them on a large scale. Ocular biomarkers, such as those obtained through eye tracking (ET) technology, have the potential as a diagnostic tool due to their accuracy, affordability, and ease of use. In this study, we show that eye movement (EM) metrics from an interleaved Pro/Anti-saccade (PS/AS) ET task can differentiate between cognitively normal (CN) and MCI subjects and that the presence of Aβ brain deposits, a biomarker of AD, significantly affects performance on these tasks. Individuals with Aβ deposits (Aβ+) performed worse than those without (Aβ-). Our findings suggest that eye-tracking measurements may be a valuable tool for detecting amyloid brain pathology and monitoring changes in cognitive function in CN and MCI individuals over time.Clinical Relevance- The PS/AS paradigm, which measures saccadic eye movements, can accurately detect subtle cognitive impairments and changes in the brain associated with Alzheimer's disease in CN and MCI individuals. This makes it a valuable tool for identifying individuals at risk for cognitive decline and tracking changes in cognitive function over time.