Improvement In Neurocognitive Function Research Articles

Cerebral Cortical Gray Expansion Associated with Two Second-Generation Antipsychotics

Second-generation antipsychotics (SGAs) differ from first-generation antipsychotics (FGAs) with respect to induction of less extrapyramidal morbidity, partially reducing negative symptoms, and causing modest improvement in neurocognitive functioning in patients with schizophrenia. SGAs demonstrate 5-HT2a antagonism. Differential effects of SGAs and FGAs on cortical gray volumes are explored herein. Cerebral cortical gray was examined volumetrically in 19 patients with schizophrenia before and following 28 days of treatment with two SGAs (risperidone and ziprasidone; n = 13) or a FGA (haloperidol; n = 6). Seven (untreated) control subjects were also assessed at a similar interval. During treatment with the SGAs risperidone and ziprasidone, cerebral cortical gray of 13 patients with schizophrenia expanded 20.6 +/- 11.4 cc (p < .0005). Six patients receiving the FGA haloperidol, as well as 7 control subjects, showed no change in cortical gray volumes (p = .983 and p = .932, respectively) at the time of reassessment. Volumetric increase of cerebral cortical gray occurred early in the course of treatment with the SGAs ziprasidone and risperidone, but not with the FGA haloperidol. Such cortical gray expansion may be relevant to the reported enhanced neurocognition and quality of life associated with SGA treatment.

Normalizing hematocrit in dialysis patients improves brain function.

Recombinant human erythropoietin (rHuEPO) treatment has been shown to improve brain and cognitive function in anemic dialysis patients. Significant debate continues, however, regarding the appropriate target hematocrit (Hct) that will lead to the greatest benefits while considering possible side effects and costs of rHuEPO. Current practice results in an Hct averaging only 31% to 32% in dialysis patients, a level less than that achieved in the initial clinical trials and well less than normal. This study was designed to evaluate dialysis patients at the current practice Hct levels versus normal Hct levels (40% to 45%) to see if improvement in brain function resulted. Twenty patients with end-stage renal disease (ESRD) currently being treated with rHuEPO (mean Hct, 31.6%) were administered additional rHuEPO to reach normal Hct levels (mean, 42. 8%). Electroencephalogram (EEG) frequency analysis showed a significant decrease in EEG slowing at greater Hct values, and the auditory oddball and Continuous Performance Task tasks yielded significant electrode and time-by-electrode effects for P300 amplitude. Changes in P300 latency significantly correlated with increased Hct in the auditory oddball task. These findings suggest that further correction of anemia to normal Hct levels may result in continued improvement in neurocognitive function by improving the ability to sustain attention in easier tasks and by enhancing the ability to recognize, discriminate, and hold stimuli in memory for more difficult tasks.

Neurobehavioral Manifestations of Symptomatic HIV-1 Disease in Children: Can Nutritional Factors Play a Role?

Central nervous system (CNS) abnormalities are significant and frequent complications of human immunodeficiency virus (HIV-1) infection in infants and children. Although the predominant cause of neurological and neuropsychological abnormalities appears to be related to HIV infection of the CNS, other factors including malnutrition may also play a role. We retrospectively evaluated the association of change in body weight with changes in neurocognitive function, ventricular brain ratio, and cerebrospinal quinolinic acid levels in a small cohort of children (n=15; mean age 6.3 years) with symptomatic HIV-1 disease before and after 6 months of antiretroviral therapy with continuous intravenous infusion of zidovudine (ZVD). Significant increases in weight and neurocognitive function as well as decreases in ventricular brain ratio and cerebrospinal quinolinic acid levels were noted after therapy. Only the relation between increase in weight and decrease in ventricular brain ratio was statistically significant (P<.01); contrary to expectations, an increase in weight seemed to correlate with a decrease in neurocognitive function (NS). Another group of children treated at the same time with oral intermittent ZVD, but otherwise receiving the same care did not show the same magnitude of improvement in neurocognitive function. These results seem to suggest that general supportive and medical care as well as nutritional factors may only play a limited role in the neurocognitive improvements after antiretroviral therapy with continuous infusion ZVD. Our sample size was, however, small and the nutritional measure rather global; thus these findings have to be considered as very preliminary.

Neurocognitive impairment: the unrecognized component of dual diagnosis in substance abuse treatment.

Brief neuropsychological tests were administered to an inpatient substance abuse population to (1) evaluate the status of neurocognitive functioning at admission, (2) assess changes that may occur during the treatment program, and (3) compare various testing devices for clinical application in this setting. Patients entering a 14-day inpatient substance abuse unit were tested within a few days of admission with the Neurobehavioral Cognitive Status Examination (NCSE), the screening test for the Luria-Nebraska Neuropsychological Battery, and the Trail Making Test. Impaired neurocognitive performance was observed in approximately two-thirds of patients; the most frequently compromised areas of functioning involved attention and memory, calculation, abstraction, ability to follow complex commands, and visuospatial skills. Readministration of the NCSE prior to discharge detected a statistically significant improvement in attentional abilities, and a tendency toward improvement for verbal comprehension and abstraction. Discussion of these findings addresses several issues: (1) the frequency and degree of impairment in this population; (2) the observed variability of cognitive functioning; (3) the question of clinical improvement in neurocognitive functioning observed during a program of this length; and (4) a preference for the NCSE in this setting. The authors argue for the routine neuropsychological assessment of substance abusers, and discuss the above issues in terms of their implications for treatment at both the individual and programmatic level. Discussion of two cases illustrates the application of the NCSE, and the effect of finding organic impairment on staff attitudes and treatment issues.