Damage to different regions of the brain can cause a variety of neuropsychological deficits, including specific disturbances of language, memory, perception and motor function. A significant number of brain-damaged patients are unaware of their deficits, even when they are profound and have debilitating effects on patients' performance. This article reviews clinical observations and experimental investigations concerning unawareness of deficits, considers methodological issues, and critically evaluates different interpretations of the phenomenon. An integrative theoretical framework is proposed to account for unawareness of deficits in diverse neuropsychological syndromes. Possible directions for future research are outlined.

Objective Report the prevalence of lifetime and military-related traumatic brain injuries (TBIs) in Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) veterans and validate the Boston Assessment of TBI–Lifetime (BAT-L). Setting The BAT-L is the first validated, postcombat, semistructured clinical interview to characterize head injuries and diagnose TBIs throughout the life span. Participants Community-dwelling convenience sample of 131 OEF/OIF veterans. Design TBI criteria (alteration of mental status, posttraumatic amnesia, and loss of consciousness) were evaluated for all possible TBIs, including a novel evaluation of blast exposure. Main Measures BAT-L, Ohio State University TBI Identification Method (OSU-TBI-ID). Results About 67% of veterans incurred a TBI in their lifetime. Almost 35% of veterans experienced at least 1 military-related TBI; all were mild in severity, 40% of them were due to blast, 50% were due to some other (ie, blunt) mechanism, and 10% were due to both types of injuries. Predeployment TBIs were frequent (45% of veterans). There was strong correspondence between the BAT-L and the OSU-TBI-ID (Cohen κ = 0.89; Kendall τ-b 0.95). Interrater reliability of the BAT-L was strong (κs >0.80). Conclusions The BAT-L is a valid instrument with which to assess TBI across a service member’s lifetime and captures the varied and complex nature of brain injuries across OEF/OIF veterans’ life span.

Two new measures were developed to assess quantitatively the degree to which patients with Alzheimer's disease (AD) are aware of their memory deficit, and to evaluate the relation between dementia severity and awareness of deficit. Results of a questionnaire measure indicated that AD patients rated their own difficulties with cognitive activities of daily life significantly lower than relatives rated patients' problems, and this discrepancy was related to patients' dementia severity. On another measure involving task performance predictions, AD patients were inaccurate in predicting their performance on most cognitive tasks when compared to both their actual performance and relatives' predictions, despite generally accurate prediction of their relatives' performance on the same tasks. These results are discussed in terms of a breakdown in metacognitive processes.

Previous research has demonstrated that performance on implicit memory tests such as word completion and identification does not require elaborative study processing, whereas performance on explicit memory tests such as recall and recognition is strongly dependent on elaborative study processing. We examined the effects of elaborative and nonelaborative study tasks on implicit memory for unitized and nonunitized word pairs. Unitized pairs were represented by common idioms (e.g., SOUR GRAPES) and highly related paired associates (e.g., TABLE-CHAIR). Nonunitized pairs were represented by British idioms (e.g., CURTAIN LECTURE) and unrelated paired associates (e.g., SALT-CHAIR). Implicit memory was assessed with a free-association test. Results of four experiments indicated that implicit memory for unitized pairs was independent of several, though not all, types of study processing that affected explicit recall. In contrast, implicit memory for nonunitized pairs was dependent on the same types of elaborative study processing that influenced explicit recall. The findings are discussed in the context of activation and episodic views of implicit memory. Recent research has demonstrated that information acquired during a specific learning episode can facilitate performance on various tests that do not make explicit reference to the episode, such as word stem and fragment completion (e.g.

Patients with PTSD were more likely to meet criteria for memory impairment and to show impairment in any domain than controls. Patients with PTSD and comorbid depression were no more likely to be impaired in any cognitive domain or to have lower scores on individual cognitive tasks than patients with PTSD alone. Clinicians noting cognitive impairment in individuals with PTSD should exercise caution before ascribing that impairment to another etiology if deficits are limited to memory.