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Relations between visceral and behavioral function in men at bedrest.

Multiple physiological measurements as well as a self-assessment of arousal was made in eight men on the first, third, and fifth days of bedrest. On the third day, additional measurements of performance on memory and dexterity tasks were made. Univariate analysis did not reveal any physiological variable to either predict subsequent performance well or to co-vary acutely with it; however, self-rating scores did prove to be useful predictors of subsequent performance. Principal components analysis suggested an "alertness" factor comprised of physiological measures as well as self-ratings which helped in predicting better performance. Although the individual patterns of correlations between variable on each of the three test days was variable, even more variability between subjects was found on the performance testing day. We believe this effect of behavioral activation may be due to the injection of common, slow temporal trends into many of the different data sets.

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Sequential cranial MR findings of asymptomatic and neurologically symptomatic HIV+ subjects.

PURPOSE: To compare results of a prospective MR and clinical reevaluation of HIV+ asymptomatic and neurologically symptomatic subjects who had had initially abnormal cranial studies to determine what cranial MR changes occur and how these changes correlate with serial neurologic and neuropsychologic findings. PATIENTS AND METHODS: Thirty-one asymptomatic (n = 20) and neurologically symptomatic (n = 11) subjects seropositive for the human immunodeficiency virus (HIV+) were prospectively reevaluated by cranial magnetic resonance (MR) one to two years following an initially abnormal MR of the brain. RESULTS: All 31 HIV+ subjects with initial abnormal MR had abnormal follow-up scans (showing atrophy and/or white matter lesions). Twenty-seven showed no progression of MR abnormalities (among whom were 18 with minimally abnormal scans who remained asymptomatic with improved or static neuropsychologic performance). Of the four subjects with scan changes (all with clinically suspected HIV encephalopathy), one showed MR, clinical, and neuropsychologic test improvement; the remaining three showed MR (n = 3), neurologic (n = 3), neuropsychologic (n = 1) worsening and autopsy (n = 1) confirmed the presence of HIV-1 containing multinucleated giant cells in the brain. CONCLUSIONS: This study suggests that: 1) Progression of intracranial MR abnormalities due to HIV-1 is seen only in a minority of HIV+ subjects over a 1- to 2-year time period, only in those neurologically symptomatic, and correlates with clinical deterioration. 2) Minor cerebral MR abnormalities seen in HIV+ subjects who remain neurologically asymptomatic do not change over a 1- to 2-year period. 3) Although HIV is known to infect the brain early, it may, nevertheless, not routinely do significant anatomical damage early on in the disease, as based on MR criteria.

Acquired Immunodeficiency Syndrome↗