PubMed · 14264702
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R VIZIOLI, F LIBERATI. [EPILEPTIC AUTOSCOPY].. https://pubmed.ncbi.nlm.nih.gov/14264702/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The nogo potentials (N2/P3) were studied in a precuing auditory reaction time task in human subjects who had to either perform a button-press response (Press condition) or imagine they were performing it (Imagine condition). In the full precue condition (the subjects knew in advance which response they had to perform/imagine), in 25% of the trials, a nogo signal instructed the subject not to perform or not to imagine the prepared action. Clear N2/P3 components were obtained on nogo trials on the Press trials, but also on the Imagine ones: the N2 was of similar amplitude in both conditions, whereas the P3 was of smaller amplitude in the Imagine condition. The presence of nogo potential in motor imagery is discussed in terms of the functional significance of the N2/P3 complex.
OBJECTIVES: To define the clinical and polysomnographic features of a distinct variant of obstructive sleep-disordered breathing that is remarkably mild during rapid eye movement (REM) sleep. DESIGN: Observational study and evaluation of polysomnographic and clinical records. SETTING: American Academy of Sleep Medicine-accredited multidisciplinary sleep disorders center and laboratory. PATIENTS: 35 medication-free subjects with clinical and polysomnographic severe obstructive sleep-disordered breathing selected for dominance of 1 of 2 disordered breathing patterns. INTERVENTIONS: Positive airway pressure titration. MEASUREMENTS AND RESULTS: Nasal pressure was used to score respiratory events. Sleep was scored by both the standard criteria and cyclic alternating pattern (CAP), and the distribution of respiratory events was tabulated and analyzed. A distinct clinical and polysomnographic syndrome emerged, CAP-dominant sleep-disordered breathing, characterized by severe relatively short cycle obstructive events during non-REM sleep that were mild in REM sleep. Characteristics include lower body mass index, fewer apneas, and a lower hypoxic burden as reflected by frequency and severity of nocturnal oxygen saturation. During positive pressure titration, a remarkable respiratory instability emerged selectively during CAP, in contrast to stability during REM sleep. This partial treatment failure was associated with persistent clinical symptoms. CONCLUSIONS: This variant of sleep apnea may reflect a dominant component of respiratory instability and periodic breathing coupled with upper-airway obstruction. Its existence questions the conventional practice of calculating global respiratory indexes. Besides positive airway pressure, measures to treat periodic breathing may be required.
OBJECTIVES: The Standards of Practice Committee of the American Sleep Disorders Association has supported the use of actigraphy in the assessment of sleep disorders. Pollak et al disagree. The objective of this paper is to identify and critically evaluate several theoretic and methodologic issues that are central to these divergent views regarding the valid use of actigraphy for sleep assessment. DESIGN: Critical review, analysis, and comment. SETTING: N/A. PATIENTS/PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: N/A. CONCLUSIONS: (1) Coefficients of the validity of actigraphy exceed those associated with common medical tests and the best psychological tests. (2) Reasons why actigraphy should be held to a substantially higher empirical standard than common medical tests and the best psychological tests have yet to be advanced. (3) Differences between actigraphy and polysomnography are not random and can be reduced. (3a) Sleep onset is a gradual rather than a discrete process. Actigraphy keys on an earlier phase of the sleep-onset process than does polysomnography, resulting in systematic rather than random differences. (3b) A sleep switch device can be used to substantially increase the accuracy of sleep-onset times. (3c) The residual unreliability of polysomnographic data explains a portion of the differences between actigraphy and polysomnography. Actigraphy cannot be expected to agree more completely with polysomnography than polysomnography does with itself. (4) Complete agreement between actigraphy and polysomnography has been presumed, but achieving such a limit is theoretically impossible. Some lower maximum agreement limit should be identified. (5) Conclusions that actigraphy is not an accurate sleep-wake indicator and that it is inappropriate to infer sleep from actigraphy data are not supported by the findings. Conclusions reached, including caveats, by the Standards of Practice Committee remain supported.