Brenda D. Townes

THE COST TO THE CENTRAL NERVOUS SYSTEM OF CLIMBING TO EXTREMELY HIGH ALTITUDE

To assess the possibility that climbing to extremely high altitude may result in hypoxic injury to the brain, we performed neuropsychological and physiologic testing on 35 mountaineers before and 1 to 30 days after ascent to altitudes between 5488 and 8848 m, and on 6 subjects before and after simulation in an altitude chamber of a 40-day ascent to 8848 m. Neuropsychological testing revealed a decline in visual long-term memory after ascent as compared with before; of 14 visual items of information on the Wechsler Memory Scale, fewer were recalled after ascent by both the simulated-ascent group (a mean [+/- SD] of 10.14 +/- 1.68 items before, as compared with 7.00 +/- 3.35 items after; P less than 0.05) and the mountaineers (12.33 +/- 1.96 as compared with 11.36 +/- 1.88; P less than 0.05). Verbal long-term memory was also affected, but only in the simulated-ascent group; of a total of 10 words, an average of 8.14 +/- 1.86 were recalled before simulated ascent, but only 6.83 +/- 1.47 afterward (P less than 0.05). On the aphasia screening test, on which normal persons make an average of less than one error in verbal expression, the mountaineers made twice as many aphasic errors after ascent (1.03 +/- 1.10) as before (0.52 +/- 0.80; P less than 0.05). A higher ventilatory response to hypoxia correlated with a reduction in verbal learning (r = -0.88, P less than 0.05) and with poor long-term verbal memory (r = -0.99, P less than 0.01) after ascent. An increase in the number of aphasic errors on the aphasia screening test also correlated with a higher ventilatory response to hypoxia in both the simulated-ascent group (r = 0.94, P less than 0.01) and a subgroup of 11 mountaineers (r = 0.59, P less than 0.05). We conclude that persons with a more vigorous ventilatory response to hypoxia have more residual neurobehavioral impairment after returning to lower elevations. This finding may be explained by poorer oxygenation of the brain despite greater ventilation, perhaps because of a decrease in cerebral blood flow caused by hypocapnia that more than offsets the increase in arterial oxygen saturation.

Adult attention-deficit hyperactivity disorder: Assessment guidelines based on clinical presentation to a specialty clinic

Of 143 adults presenting for attention-deficit hyperactivity disorder (ADHD) evaluation, 46 (32%) clearly met diagnostic criteria, 46 (32%) clearly did not meet diagnostic criteria, and another 51 (36%) with current ADHD-like features did not meet criteria due to either a lack of childhood history and/or complicating severe psychiatric or substance abuse comorbidity. The three groups were similar in demographics, psychiatric diagnosis, psychiatric symptom severity, and functional impairment. Compared with the group not meeting ADHD criteria, patients with ADHD had more frequent histories of learning disability in childhood, poorer reading scores on the Wide-Range Achievement Test (WRAT), poorer scores on the Continuous Performance Test (CPT), and higher scores on the Wender-Utah Rating Scale (WURS) for ADHD. Patients in the ambiguous ADHD category had higher rates of current substance abuse than the other two groups. While this group resembled the non-ADHD group in having a low incidence of learning disability and normal reading scores, their poor performance on the CPT and high scores on the WURS more closely resembled those of ADHD patients. These findings suggest that there are a few rating scales, testing instruments, and lifetime history characteristics that help to clarify the difficult diagnostic distinction between adult patients who do and do not have ADHD.

A Randomized Study of Carbon Dioxide Management during Hypothermic Cardiopulmonary Bypass

Eighty-six patients undergoing coronary artery bypass graft (n = 63) or intracardiac (n = 23) surgery were randomly assigned with respect to the target value for PaCO2 during cardiopulmonary bypass. In 44 patients the target PaCO2 was 40 mmHg, measured at the standard electrode temperature of 37 degrees C, while in 42 patients the target PaCO2 was 40 mmHg, corrected to the patients rectal temperature (lowest value reached: mean 30.1, SD 1.9 degrees C). Other salient features of bypass management include use of bubble oxygenators without arterial filtration, flows of 1.8-2.4 l.min-1.m-2, mean hematocrit of 23%, and mean arterial blood pressure of approximately 70 mmHg, achieved by infusion of phenylephrine or sodium nitroprusside. Neuropsychologic function was assessed with series of tests administered on the day prior to surgery, just before discharge from the hospital (mean 8.0, SD 5.8 days postoperatively, n = 82), and again 7 months later (mean 220.7, SD 54.4 days postoperatively, n = 75). The scores at 8 days showed wide variability and generalized impairment unrelated to the PaCO2 group or to hypotension during cardiopulmonary bypass. At 7 months no significant difference was observed in neuropsychologic performance between the PaCO2 groups. Regarding cardiac outcome, there were no significant differences between groups in the appearance of new Q-waves on the electrocardiogram, the postoperative creatine kinase-MB fraction, the need for inotropic or intraaortic balloon pump support, or the length of postoperative ventilation or intensive care unit stay. These findings support the hypothesis that CO2 management during cardiopulmonary bypass at moderate hypothermia has no clinically significant effect on either neurobehavioral or cardiac outcome.

Neuropsychological Functions in Idiopathic Occipital Lobe Epilepsy

Summary: Purpose: Despite the benign prognoses of idiopathic partial epilepsies, particularly regarding the response of seizures to treatment, some evidence now exists that patients with such disorders may have subtle neuropsychological deficits. This study was designed to investigate several modalities of neuropsychological functioning in a group of 21 patients, ranging from 6 to 14 years of age, with idiopathic occipital lobe epilepsy (IOLE). The case patients were compared with 21 healthy controls matched for age, sex, and socioeconomic status.

Cognition and metacognition at extreme altitudes on Mount Everest.

The FACTRETRIEVAL2 test battery, which assesses both retrieval of general information from memory and metacognition about that retrieval, was administered to people before and after a recent expedition to Mount Everest and at extreme altitudes above 6,400 m (higher than any mountain in North America or Europe). The major findings were as follows: First, the same extreme altitudes already known to impair learning did not affect either accuracy or latency of retrieval, and this robustness of retrieval occurred for both recall and forced-choice recognition. Second, extreme altitude did affect metacognition: The climbers showed a decline in their feeling of knowing both while at extreme altitude and after returning to Kathmandu (i.e., both an effect and an aftereffect of extreme altitude). Third, extreme altitude had different effects than alcohol intoxication (previously assessed by Nelson. McSpadden, Fromme, & Marlatt, 1986). Alcohol intoxication affected retrieval without affecting metacognition, whereas extreme altitude affected metacognition without affecting retrieval; this different pattern for extreme altitude versus alcohol intoxication implies that (a) hypoxia does not always yield the same outcome as alcohol intoxication and (b) neither retrieval nor metacognition is strictly more sensitive than the other for detecting changes in independent variables.

Developing and testing a decision aid for birth planning decisions

Abstract The article describes the development of a scheme to aid people in thinking through their decisions about whether to have a (another) child. First, a list of values (utilities) was gleaned from the literature, values (utilities) that children apparently fulfill for parents. Following this, seven married couples participated in the gradual modification of the list into a hierarchically structured set of values (utilities). Then two large groups of subjects were used to test the degree to which the hierarchy was meaningful to persons other than those who had participated in its development. Finally, as a feasibility study, two more couples (1) used the hierarchy to decompose their birth decisions into manageable chunks, (2) evaluated the chunks to indicate the relative utility of each chunk, and (3) assessed their subjective probabilities that those utilities represented in each chunk would be satisified if they were to decide to have the child. Computation of subjective expected utilities for having and for not having the child for each member of the couples permitted accurate postdiction of their birth decisions.

Relationships Between IQ and Neuropsychological Measures in Neuropsychiatric Populations: Within-Laboratory and Cross-Cultural Replications Using WAIS and WAIS-R

Several studies have reported positive correlations between measures of intelligence (a quasi-subject variable) and level of performance on neuropsychological tests; few, however, have presented test results by IQ grouping, which could be useful for comparative purposes. The present study examined the relationships of WAIS and WAIS-R Full Scale IQ to performance on a neuropsychological battery consisting of the Halstead-Reitan Battery (HRB), the Wide Range Achievement Test (WRAT), and the Wechsler Memory Scale (WMS). Four mixed neuropsychiatric samples provided cross-cultural and within-laboratory replications, two tested with WAIS and two with WAIS-R. Means and standard deviations for each measure were presented by five IQ levels within each sample. IQ was strongly related to scores on problem-solving tasks, auditory and linguistic measures, memory tasks, academic achievement levels, and tactual imperceptions, while motor functioning and sensory suppressions were less strongly related to IQ. IQ level was related to educational level in all samples. Correlations of years of education with dependent variables in the two WAIS-R samples were strong and replicable for WRAT scores, verbal memory measures, linguistic errors on the Aphasia Screening Test, and finger-tapping speeds but not for other HRB measures. Finally, IQ-HRB relationships were compared to those reported for other populations.

Subjective expected utility and the prediction of birth-planning decisions

This article is a companion to an earlier one which detailed the logic development and preliminary testing of a decision aid for birth planning. In brief the scheme consists of a hierarchical organized set of value categories related to having a child to which the decision maker assigns weights to indicate the relative utility of that category to him or her. Following that the decision maker assigns subjective probabilities to the categories to indicate how likely it is that these values would be fulfilled if a positive decision were made about having another child (or first child) in the next 2 years. The hierarchy breaks down into 3 main value-types: values centered on self and spouse (personal identity parenthood and well-being of family); values centered on childen (family characteristics health and well-being of children); and values centered on significant others (family friends and society). Married couples with variously sized families completed the birth-planning hierarchy outlined above. Predictions were made about a child-bearing decision in the next 2 years. Results showed that a subjective expected utility model predicted best (73% correct) for those couples who had not yet attained desired family size. Errors in prediction were not random and the reasons for false positives (couples predicting another child but not having one) are explored including the fact that the hierarchy does not capture the inherent ambivalence of couples; this concept of assenting on a questionnaire vs. real indecision on family continuation is discussed in terms of a decision threshold theory.

Infants' Attachment to Inanimate Objects: A Cross-Cultural Study

Winnicott ( 1953) was the first investigator in the Western literature who paid due attention to the rather common phenomenon of a “security” blanket. In his report he introduced the term “transitional object” and described it as the first not-me possession of a child which plays an important role in ego development. Since then, many reports on this topic have appeared, mainly in the psychoanalytic literature (Stevenson, 1954; Provence and Ritvo, 196 1 ; Provence and Lipton, 1962; Schaffer and Emerson, 1964; Coppolillo, 1967; Greenacre, 1969; Fintzy, 1971), with a few experimental studies (Weisberg and Russell, 1971; Gershaw and Schwarz, 1971). Tolpin (1971) hypothesized that a “transitional object” aids the child in the separation-individuation process, and Busch et al. (1 973) rigorously defined and described the “primary transitional object.” Most recently, Passman and Weisberg (1 975) reported that mother and blanket share similar functional properties in reducing fearfulness and generating exploratory behavior of the children in an experimental setting. Most of the observations reported in the literature have been limited to Western culture, as seen in England and the U.S.A., and were primarily concerned with the characteristics and functions of the transitional object. Little is known concerning the rates at which infants develop attachment behavior toward inanimate objects and how this behavior

Issues in design and analysis of a randomized clinical trial to assess the safety of dental amalgam restorations in children

The Casa Pia Study of the Health Effects of Dental Amalgams in Children is a randomized clinical trial designed to assess the safety of low-level mercury exposure from dental amalgam restorations in children. It is being carried out in 507 students (8 to 12 years of age at enrollment) of the Casa Pia school system in Lisbon, Portugal, by an interdisciplinary collaborative research team from the University of Washington (Seattle) and the University of Lisbon, with funding from the National Institute of Dental and Craniofacial Research. Since the goal of the trial is to assess the safety of a treatment currently in use, rather than the efficacy of an experimental treatment, unique design issues come into play. The requirements to identify as participants children who have extensive unmet dental treatment needs and who can be followed for 7 years after initial treatment are somewhat in conflict, since those with the most treatment needs are usually in lower socioeconomic categories and more difficult to track. The identification of a primary study outcome measure around which to design the trial is problematic, since there is little evidence to indicate how health effects from such low-level exposure would be manifested. The solution involves the use of multiple outcomes. Since there are concerns about safety, multiple interim comparisons over time between treatment groups are called for which, in conjunction with the use of multiple outcomes, require an extension of statistical methodology to meet this requirement. Ethical questions that have to be addressed include whether assent of the children participating is required or appropriate, and whether the director of the school system, who is the legal guardian for approximately 20% of the students who are wards of the state and live in school residences, should provide consent for such a large number of children. Approaches taken to address these and other design issues are described.