Encyclopedia of Clinical Neuropsychology

2011 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan


  • Chris Loftis
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-79948-3_2122



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.

Cross References

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Chris Loftis
    • 1
  1. 1.National Council for Community Behavioral Healthcare STG InternationalAlexandriaUSA