Search

Introduction: Recent introductions of disease-modifying treatments for Alzheimer's disease have re-invigorated the cause of early dementia detection. Cognitive "paper and pencil" tests represent the bedrock of clinical assessment, because they are cheap, easy to perform, and do not require brain imaging or biological testing. Cognitive tests vary greatly in duration, complexity, sociolinguistic biases, probed cognitive domains, and their specificity and sensitivity of detecting cognitive impairment (CI). Consequently, an ecologically valid head-to-head comparison seems essential for evidence-based dementia screening., Method: We compared five tests: Montreal cognitive assessment (MoCA), Alzheimer's disease assessment scale-cognitive subscale (ADAS), Addenbrooke's cognitive examination (ACE-III), euro-coin handling test (Eurotest), and image identification test (Phototest) on a large sample of seniors (N = 456, 77.9 ± 8 years, 71% females). Their specificity and sensitivity were estimated in a novel way by contrasting each test's outcome to the majority outcome across the remaining tests (comparative specificity and sensitivity calculation [CSSC]). This obviates the need for an a priori gold standard such as a clinically clear-cut sample of dementia/MCI/controls. We posit that the CSSC results in a more ecologically valid estimation of clinical performance while precluding biases resulting from different dementia/MCI diagnostic criteria and the proficiency in detecting these conditions., Results: There exists a stark trade-off between behavioral test specificity and sensitivity. The test with the highest specificity had the lowest sensitivity, and vice versa. The comparative specificities and sensitivities were, respectively: Phototest (97%, 47%), Eurotest (94%, 55%), ADAS (90%, 68%), ACE-III (72%, 77%), MoCA (55%, 95%)., Conclusion: Assuming a CI prevalence of 10%, the shortest (∼3 min) and the simplest instrument, the Phototest, was shown to have the best overall performance (accuracy 92%, PPV 66%, NPV 94%)., (© 2024 S. Karger AG, Basel.)

The P3 can arguably be named the most intensely studied ERP. In spite of more than 40 years of research, fundamental questions regarding the nature of its neural generators remain unresolved. While most studies conclude that the P3 is a true classical "endogenous" potential, and that its surface potential distribution remains constant across sensory modalities, these results are largely based on low-density EEG recordings, without the use of high-resolution methods such as the spherical spline Laplacian (SSL). Seventeen healthy participants performed a three-stimulus oddball task in visual and auditory modality while their EEG was recorded using a 128-channel system. Comparison of amplitude-normalized SSL estimated P3 brain-surface potentials, and analysis of spatial and temporal correlations revealed significant differences between visual and auditory evoked P3 topographies from target and distractor stimuli (but not target minus frequent or distractor minus frequent comparisons). Based on these results, we postulate the likely existence of at least some sensory modality-specific neuronal generators of the P3., (© 2016 Society for Psychophysiological Research.)

Parkinson's disease (PD) patients show signs of cognitive impairment, such as executive dysfunction, working memory problems and attentional disturbances, even in the early stages of the disease. Though motor symptoms of the disease are often successfully addressed by dopaminergic medication, it still remains unclear, how dopaminergic therapy affects cognitive function. The main objective of this study was to assess the effect of dopaminergic medication on visual and auditory attentional processing. 14 PD patients and 13 matched healthy controls performed a three-stimulus auditory and visual oddball task while their EEG was recorded. The patients performed the task twice, once on- and once off-medication. While the results showed no significant differences between PD patients and controls, they did reveal a significant increase in P3 amplitude on- vs. off-medication specific to processing of auditory distractors and no other stimuli. These results indicate significant effect of dopaminergic therapy on processing of distracting auditory stimuli. With a lack of between group differences the effect could reflect either 1) improved recruitment of attentional resources to auditory distractors; 2) reduced ability for cognitive inhibition of auditory distractors; 3) increased response to distractor stimuli resulting in impaired cognitive performance; or 4) hindered ability to discriminate between auditory distractors and targets. Further studies are needed to differentiate between these possibilities., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Objective: This study explored event-related desynchronization (ERD) and synchronization (ERS) in amyotrophic lateral sclerosis (ALS) to quantify cortical sensorimotor processes during volitional movements. We furthermore compared ERD/ERS measures with clinical scores and movement-related cortical potential (MRCP) amplitudes., Methods: Electroencephalograms were recorded while 21 ALS patients and 19 controls performed two self-paced motor tasks: sniffing and right index finger flexion. Based on Wavelet analysis the alpha and beta frequency bands were selected for subsequent evaluation., Results: Patients generated significantly smaller resting alpha spectral power density (SPD) and smaller beta ERD compared to controls. Additionally patients exhibited merely unilateral post-movement ERS (beta rebound) whereas this phenomenon was bilateral in controls. ERD/ERS amplitudes did not correlate with corresponding MRCPs for either patients or controls., Conclusions: The smaller resting alpha SPD and beta ERD and asymmetrical appearance of beta ERS in patients compared to controls could be the result of pyramidal cell degeneration and/or corpus callosum involvement in ALS., Significance: These results support the notion of reduced movement preparation in ALS involving also areas outside the motor cortex. Furthermore post-movement cortical inhibition seems to be impaired in ALS. ERD/ERS and MRCP are found to be independent measures of cortical motor functions in ALS., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Our aim was to investigate changes in movement-related cortical potentials (MRCPs) in ALS patients with different degrees of upper motor neuron (UMN) involvement. Since respiratory failure is the main cause of death in ALS, changes in inspiratory-related (sniffing) potentials were studied in addition to finger-flexion-related potentials. Subjects (21 ALS, 19 controls) performed two self-paced motor tasks while their EEGs were recorded. The first task required flexions of the right index finger and the second, brisk nasal inspirations. The early (BP1), late (BP2) and motor potential (MP) components of MRCPs were evaluated. Results showed that patients generated higher MRCPs than controls. However, this effect was most significant in the subgroup of patients with low UMN burden (LUB). The high UMN burden (HUB) subgroup did not differ from controls, but had significantly lower MP amplitudes than the LUB subgroup. Progressive UMN deterioration was associated with an initial increase, followed by a later decrease, in MP amplitudes in ALS. In conclusion, the increased MRCPs in LUB compared to HUB patients indicate different processes of ALS pathophysiology that force opposing changes in MRCP amplitudes.

Higher states of consciousness in which the human mind can transcend the boundaries of logic and reason are envisioned as natural to the experience and potential growth of every human being. So far they have been mostly monitored by electrophysiological methods. In this study we were particularly interested in discovering the molecular transcriptional basis of higher states of consciousness. In addition to phenomenological reports of meditators who participated in this study the generated higher states of consciousness were also EEG recorded. We assessed the whole genome gene expression analysis of long-term meditators in four separate trials and detected significant differential gene expression in association with higher states of consciousness. The number of differently expressed genes as well as high proportion of genes themselves differed between meditators. Despite this, gene ontology enrichment analysis found significant biological and molecular processes shared among meditators' higher state of consciousness., (Copyright © 2012 Elsevier Inc. All rights reserved.)