Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan


  • Chris LoftisEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_2122


Awareness; Consciousness; Vigilance; Watchfulness


A state of being mentally perceptive and responsive to external stimuli. A “readiness to respond” that can be detected by electroencephalography (EEG). Alertness is susceptible to fatigue; maintaining a constant level of alertness is difficult, particularly for monotonous tasks demanding continuous attention. Stimulants such as nicotine, caffeine, and amphetamines can temporally boost alertness. Diminished alertness is often associated with the physiological response of yawning, which may boost the alertness of the brain. Impaired alertness is a common symptom of a number of conditions, including narcolepsy, attention deficit disorder, traumatic brain injury, chronic fatigue syndrome, depression, Addison’s disease, and sleep deprivation. Although a broad neurological network modulates alertness, the basal forebrain and a distinct group of neurons located in the periventricular areas of the midbrain, pons, and...

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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.National Council for Community Behavioral HealthcareAlexandriaUSA