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Caffeine and attention
Published in B.S. Gupta, Uma Gupta, Caffeine and Behavior, 2020
Kerr et al.25 examined the separate and combined effects of nicotine, alcohol, and caffeine on performance. One of the tasks was a dual task involving compensatory tracking and detection of peripheral visual stimuli. In addition, the subject’s critical flicker fusion threshold (CFF) was measured and used as an index of the state of CNS arousal. Tracking accuracy over four trials of 60 sec and the reaction time to 40 lights (10 per trial) were assessed prior to treatment (baseline test) and at 1, 2, 3, and 4 hours after administration of treatment. Alcohol alone was found to impair significantly tracking accuracy, whereas all drug combinations which included nicotine, or 250 mg of caffeine alone, produced an improvement of tracking performance. There were no drug effects on the reaction time to the simultaneously presented visual stimuli. The effect of caffeine on tracking performance did not vary as a function of the time of administration. Because caffeine did not affect the CFF, the authors suggested that the enhancing effects of caffeine on tracking performance were not related to an increase in the general level of arousal. Instead, a more specific action of caffeine on information processing might be involved.
Early detection of dementia
Published in Stephen Curran, John P. Wattis, Practical Management of Dementia, 2018
Sonja Krüger, Miguel A. Bertoni, Stephen Curran
Critical Flicker Fusion Threshold (CFFT) is a well-established neurophysiological technique that has been extensively studied in young and older healthy volunteers. The neurophysiological basis of flicker perception is well described.34 Flickering light directly influences cortical activity (measured by electroencephalogram, EEG), and although flickering light is able to initiate neuronal activity in various parts of the visual system (from retina to cortex), the temporal resolution of CFFT appears to be determined principally by the occipital cortex. Above a particular frequency, flickering light does not appear to flicker and the point at which this occurs is the CFFT and is a measure of the information-processing capacity of the central nervous system. In the ascending mode, the frequency of flicker is gradually increased until the flickering lights appear to stop flickering – this is the ascending threshold. In the descending mode, the frequency of flicker is gradually decreased until the lights appear to start flickering – this is the descending threshold. The CFFT is the average of the ascending and descending thresholds.
Clinical Characteristics of Anti-aquaporin 4 Antibody Positive Optic Neuritis in Japan
Published in Neuro-Ophthalmology, 2019
Akiko Yamagami, Masato Wakakura, Kenji Inoue, Hitoshi Ishikawa, Toshiyuki Takahashi, Keiko Tanaka
Optic neuritis was diagnosed based on interview, past history, and ophthalmologic examinations (visual acuity, intraocular pressure, flicker fusion threshold, status of relative afferent pupillary defect, slit lamp examination, fundus examination, visual field test, fundus fluorescein angiography, and head MRI). Measurements of anti-AQP4 antibody were performed after obtaining informed consent, and blood was collected before treatment for optic neuritis or during follow-up observation. After collection, the blood sample was kept cold on ice and transported to the Department of Neurology, Niigata University School of Medicine or the Department of Neurology, Tohoku University School of Medicine for anti-AQP4 antibody testing. Anti-AQP4 antibody positivity was determined qualitatively using a cell-based assay (CBA).14,15