A proposed disorder (listed in dsm-ivtr appendix b, “criteria sets and axes provided for further study”) whose essential features are acquired cognitive impairment and behavioral disturbance that develop after head trauma. The cognitive and neurobehavioral sequelae appear within 4 weeks of experiencing the trauma and are accompanied by somatic complaints (headache, dizziness, noise intolerance), emotional changes (irritability, depression, anxiety), difficulty in concentration, insomnia, and reduced tolerance to alcohol. Physical examination and laboratory tests give evidence of cerebral damage.