Role of frontal cortex in inferential reasoning: evidence from the word context test.

PROBLEM: Inferential reasoning in language involves the ability to deduce information based on context and prior experience. This ability has been generally studied as a right-hemisphere function. Recent research, however, has suggested that inferencing involves anterior regions of both the left and right hemispheres. METHODS: We further explored this idea by testing a group of non-aphasic, focal frontal patients (right and left hemisphere) on a new test of inferencing, the Word Context Test. The Word Context Test requires examinees to identify the meaning of a made-up word (e.g., prifa) based on its use in a series of sentences. FINDINGS: Patients with frontal lobe lesions were significantly impaired on this task relative to a group of age- and education-matched controls. Contrary to earlier research focusing on a special role for the right hemisphere in inferencing, there was considerable overlap in performance of right- and left-frontal patients, with right-frontal patients performing better. CONCLUSIONS: These findings suggest that inferencing is disrupted following focal frontal injury and have implications for discourse comprehension in non-aphasic patients.     

Rare Localizations of the Hydatid Disease. Experience from a Single Center

Hydatid disease is a rare entity that mostly affects the liver and lung, but almost any organ, forming cysts. Although diagnosis is confirmed by serology and imaging studies, a high index of suspicion is required based on the epidemiological background of the patient. However, rare locations of the cysts remain a diagnostic and therapeutic dilemma. Surgical exploration with special attention to avoid parasite spillage is justified in these situations because diagnostic puncture is usually contraindicated. Pericystectomy or fenestration and omentoplasty is strongly recommended, along with the excision of involved organs when feasible.     

Response bias and aging on a recognition memory task.

Response bias reflects the decision rule an individual uses when faced with uncertainty on recognition memory tasks. Recent studies indicate frontal regions may mediate response bias performance. One theory of aging also implicates frontal lobe contributions in age-related cognitive changes. This suggests that frontal lobe changes may mediate response bias in older adults. Consistent with this frontal aging hypothesis, we predicted that response bias would become more liberal with age. Methods: Participants were 181 younger (30-49) and 112 older normal adults (75+) that were part of the California Verbal Learning Test-second edition (CVLT-2) normative sample (total n = 1078). We used parametric measures of discriminability and response bias provided by the CVLT-2 scoring program. Groups were similar in IQ and education. Multi-level regression models were created to examine the effects of moderating variables. The interaction between age and age group significantly predicted response bias. Post hoc analysis indicated that increasing age was associated with more liberal bias in the older but not in the younger group. In the light of reported relationships between frontal regions and both aging and response bias, we hypothesize that frontal changes may be the underlying mechanism explaining the increase in liberal response bias with age.     

Normative Data for 4-Year-Old Children on the California Verbal Learning Test-Children's Version

This study presents normative data for 4-year-old children on the California Verbal Learning Test-Children's Version (CVLT-C), a measure of verbal learning and memory. Norms are currently available for children 5 years and older; however, normative data are unavailable for this younger population. Forty males and 40 females comprise this normative sample of 4-year-old children. The mean number of words recalled increased from the first to the fifth learning trial, and a consistent level of recall was maintained across delay recall trials. Extra-list intrusion responses were common and these responses were more frequent than correct responses on cued but not free recall conditions. Finally, yes/no recognition testing resulted in the greatest mean number of words remembered compared to the other trials. Overall, the pattern of performance across the learning and memory variables in this younger population was similar to that of older children, but at a lower level. These data suggest that 4-year-old children are able to perform this task, making possible the use of the CVLT-C in normal and clinical populations in this age group.     

Gastric Bypass Increases Ethanol and Water Consumption in Diet-Induced Obese Rats

Background

Roux-en-Y gastric bypass surgery (RYGB) is an effective treatment for morbid obesity. Increased alcohol abuse after RYGB resulted in recommendations to exclude patients with alcohol abuse histories from RYGB. The purpose of our study was to examine the effects of a RYGB on ethanol intake in diet-induced obese rats (high-fat diet).

Methods

The animals underwent RYGB and were habituated along with their sham-operated obese controls and with lean rats to increasing concentrations of ethanol in a two-bottle choice paradigm.

Results

RYGB rats' daily consumption of ethanol averaged 2?g/kg at 2?% habituation and 3.8?g/kg at 4?% habituation, twice as much as sham-operated obese controls and 50?% more than normal-diet lean controls. Obese controls drank on average 1?g/kg of ethanol (2 and 4?%), significantly less (50?%) than lean controls did. RYGB rats when given higher ethanol concentrations (6 and 8?%) or no ethanol drank significantly more water than lean and obese controls did (66 and 100?%, respectively), and their enhanced total fluid intake was associated with increased food intake, which was significantly higher than in lean (66?% more calories; food + alcohol) and obese controls (44?% more calories). The lower alcohol intake in the obese controls than in the lean rats suggests that obesity may interfere with alcohol's rewarding effects and RYGB may remove this protective effect.

Conclusions

The overall enhancement of consummatory behaviors (both ethanol and water) suggests that RYGB may facilitate alcohol consumption, which in vulnerable individuals could lead to abuse and addiction.     

Neurocognitive functioning of adolescents: effects of protracted alcohol use

BACKGROUND: The present study examined associations between alcohol involvement in early to middle adolescence and neuropsychological (NP) functioning. METHODS: Alcohol-dependent adolescents (n = 33) with over 100 lifetime alcohol episodes and without dependence on other substances were recruited from alcohol/drug abuse treatment facilities. Comparison (n = 24) adolescents had no histories of alcohol or drug problems and were matched to alcohol-dependent participants on age (15 to 16 years), gender, socioeconomic status, education, and family history of alcohol dependence. NP tests and psychosocial measures were administered to alcohol-dependent participants following 3 weeks of detoxification. RESULTS: Alcohol-dependent and comparison adolescents demonstrated significant differences on several NP scores. Protracted alcohol use was associated with poorer performance on verbal and nonverbal retention in the context of intact learning and recognition discriminability. Recent alcohol withdrawal among adolescents was associated with poor visuospatial functioning, whereas lifetime alcohol withdrawal was associated with poorer retrieval of verbal and nonverbal information. CONCLUSIONS: Deficits in retrieval of verbal and nonverbal information and in visuospatial functioning were evident in youths with histories of heavy drinking during early and middle adolescence.     

Magnetic resonance imaging correlates of set shifting.

The purpose of this study was to examine the relationships between lobar volumes and set shifting. We studied 101 subjects, including 36 normal controls, 16 patients with probable Alzheimer's disease, 30 patients with frontotemporal dementia (FTD), and 19 patients with semantic dementia (SD), using a shifting paradigm that carefully controlled for component abilities. Subjects were administered two conditions of the Delis-Kaplan Executive Function System (D-KEFS) Design Fluency Test. In the control condition (DF:Control), examinees generated as many unique designs as possible in 60 s by drawing lines connecting only unfilled dots. In the switching condition (DF:Switch), examinees generated designs by drawing lines alternating between filled and unfilled dots. We used BRAINS2 software to generate volumes of the right and left frontal, temporal, and parietal lobes. Partial correlations and multiple regressions showed that, after controlling for Mini-Mental State Examination and DF:Control, only the right and left frontal lobe volumes significantly correlated with the DF:Switch, most clearly in the FTD and SD groups. Follow-up analyses indicated that frontal contributions to shifting were not related to working memory. Results highlight the importance of carefully controlling for component cognitive processes when studying executive functioning.     

Neuropsychological deficits associated with Alzheimer's disease in the very-old: discrepancies in raw vs. standardized scores.

The profiles of neuropsychological deficits associated with Alzheimer's disease (AD) in Young-Old (M age and 70) and Very-Old (M age > 80) patients were compared, along with possible modifying effects of apolipoprotein E (APOE) genotype on these profiles. A comprehensive battery of neuropsychological tests was administered to the two AD patient groups (Young-Old: n = 33; Very-Old: n = 48) and their respective age-matched normal control (NC) groups who remained free of dementia on follow-up examinations over a 1 to 10 year period (Young-Old: n = 43; Very-Old: n = 36). AD and NC groups did not differ in education levels or gender distributions. Young-Old AD and Very-Old AD groups were comparable in education, gender, dementia severity, and disease duration. Results showed that both AD groups achieved comparable raw scores on all the neuropsychological measures. However, when scores were standardized on the basis of performance of their respective NC groups (i.e., age-corrected z scores), Very-Old AD patients significantly outperformed Young-Old AD patients on tests of executive functions, visuospatial skills, and delayed memory. Furthermore, the relationship between age and memory and executive function deficits in AD was modified by APOE genotype. These data suggest that the profile of neuropsychological deficits associated with AD in the Very-Old lacks the disproportionate saliency of episodic memory and executive function deficits typical of the Young-Old.