Brain-mind states: I. Longitudinal field study of sleep/wake factors influencing mentation report length.

STUDY OBJECTIVES: To collect and analyze reports of mental activity across sleep/wake states. DESIGN: Mentation reports were collected in a longitudinal design by combining our Nightcap sleep monitor with daytime experience sampling techniques. Reports were collected over 14 days and nights from active and quiet wake, after instrumental awakenings at sleep onset, and after both spontaneous and instrumental awakenings from REM and NREM sleep. SETTING: All reports were collected in the normal home, work and school environments of the subjects. PARTICIPANTS: Subjects included 8 male and 8 female undergraduate students (19-26 years of age). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: A total of 1,748 reports, averaging 109 per subject, were collected from active wake across the day (n=894), from quiet wake in the pre-sleep onset period (n=58), from sleep onset (n=280), and from later REM (n=269) and nonREM (n=247) awakenings. Median report lengths varied more than 2-fold, in the order REM > active wake > quiet wake > NREM = sleep onset. The extended protocol allowed many novel comparisons between conditions. In addition, while spontaneous REM reports were longer than those from forced awakenings, the difference was explained by the time within the REM period at which the awakenings occurred. Finally, intersubject differences in REM report lengths were correlated with similar differences in waking report lengths. CONCLUSIONS: The use of the Nightcap sleep monitoring system along with waking experience sampling permits a more complete sampling and analysis of mental activity across the sleep/wake cycle than has been previously possible.

Superior episodic memory is associated with interhemispheric processing.

The dependence of episodic memories on interhemispheric processing was tested. In Experiment 1, positive familial sinistrality (FS+; e.g., presence of left-handed relatives) was associated with superior episodic memory and inferior implicit memory in comparison with negative familial sinistrality (i.e., FS-). This reflected a greater degree of interhemispheric interaction in FS+ participants, which was hypothesized as facilitating episodic memory. In Experiment 2, the authors directly manipulated inter- versus intrahemispheric processing using tests of episodic (recognition) and semantic (lexical decision) memory in which letter strings were presented twice within trial blocks. Semantic memory was superior when the 2nd presentation went to the same hemisphere as the 1st. Episodic memory, however, was superior when the 2nd presentation of a stimulus went to the opposite hemisphere. Results support an interhemispheric processing basis for episodic memories.

A molar entropy model of age differences in spatial memory.

Two very-short-term-memory, spatial scanning aging experiments were conducted involving a graphics character as a target stimulus. On the probe portion of a trial, the stimulus was presented in the same position as it was on the target portion of the trial (i.e., a same trial) 50% of the time. However, on the remaining 50% of the trials, the probe stimulus was shifted (or transposed) 1, 2, or 3 positions to the right or left of the original presentation (target) position. In Experiment 1, exposure duration was manipulated. In Experiment 2, the number of potential target display positions was manipulated. For both experiments, older adults showed larger transposition distance effects than younger adults for errors. In the past (e.g., P.A. Allen, 1990, 1991), this effect has been attributed to higher levels of internal noise (entropy) in older than younger adults. This research provides converging operations to this contention by using statistical physics methods to rigorously compute the entropy in a molar neural network across age groups. After successfully fitting the statistical mechanics model to the data, the model is proved to have external validity by fitting a simplified version of it to an earlier spatial memory aging experiment reported by P. R. Bruce and J. F. Herman (1986). The results of both traditional reaction time and error rate analyses, as well as the entropy modeling analyses, indicated that older adults exhibited higher levels of entropy than did the younger adults and that this effect appeared to be generalized across processing stage.

Age differences in entropy: primary versus secondary memory.

We report a spatial-memory scanning experiment that was used to measure age differences in entropy. A target grid consisting of four adjacent letters followed by the presentation of a single probe letter was presented on each trial. Half of the trials presented the probe stimulus in the same spatial position was the target letter (i.e., the probe letter was always a member of the positive set), and half of the trials transposed the target letter one, two, or three spaces of the right or left of the original target display position (i.e., different trials). The experiment involved blocks of primary-memory and secondary-memory tasks. Reaction-time and error-rate data, as well as entropy analyses and the fitting of an entropy model (based on Allen, Kaufman, Smith, and Propper, in press) to the empirical data indicated that older adults showed higher entropy levels than young adults. These results are interpreted in a "computational temperature" framework in which older adults' higher computational temperatures result in less efficient spatial, episodic memory functioning.

Hypnotic susceptibility, imaging ability, and anagram-solving activity.

Anagram-solving activity was examined as a function of hypnotic susceptibility level and imaging ability. In Experiment 1, anagrams that were composed of sets of letters that formed actual words (word anagrams), but when unscrambled formed other words, were compared to sets of letters that formed nonwords (nonsense anagrams). Word anagrams required more time to solve than nonsense anagrams. Also, fewer word anagrams were correctly solved compared to nonsense anagrams. Those individuals judged both high in hypnotic susceptibility and vivid in imaging ability demonstrated the best performance. In Experiment 2, anagrams that when unscrambled formed high-imagery words were compared to those that formed low-imagery words. High-imagery-word anagrams were solved more quickly and correctly than low-imagery-word anagrams. Such activity was best demonstrated by individuals who were judged to be both high in hypnotic susceptibility and vivid in imaging ability. These results are discussed in terms of strategies for solving anagrams and the individual differences that appear to be associated with using such strategies.

Cast titanium dental implants for the posterior mandible.

The purpose of this paper is to present the results of the evaluation of five patients who received titanium dental implant replicas of extracted molars and pre-molars, placed in the posterior mandible. The replicas were placed in the sockets where the molars and bicuspids had been extracted. The implant replicas were fabricated in two parts, an abutment portion and a root portion connected by a titanium screw. The root portion was made of cast titanium. The abutment portion was made of a high noble metal to which porcelain could be fused, so that the crown restoration could be made directly on the abutment. The patient's ages ranged from 27 to 63 years. Four were male and one was female. The implants were placed three to six weeks after extraction. All implants integrated. The longest follow-up with the implant in function was five years.

Influence of letter size on age differences in letter matching.

We tested healthy young and older adults on a simultaneous presentation, letter-matching task that varied letter size. The goal of the experiment was to determine if older adults' higher baseline level of internal noise would affect age differences in letter-matching performance as letter size was varied. The results indicated that both young and older adults evidenced "fast-same" effects for RT and "false-different" effects for errors. However, older adults (compared to young adults) showed a larger "false-different" effect for errors, and this effect was especially pronounced for smaller letter pairs. These results imply that older adults' higher baseline levels of internal noise result in these individuals setting "compromise criteria" that underestimate the impact of internal noise.

A technique for controlled placement of hydroxylapatite over atrophic mandibular ridges.

When hydroxylapatite is injected into a subperiosteal tunnel without placing buccolingual sutures, there is occasionally noticeable drifting of the material outside the desired area, and the labial vestibule may be diminished. By placing horizontal mattress sutures, the hydroxylapatite is controlled and ridge contour is improved. There appears to be no added morbidity from placement of the buccolingual sutures. However, because only a small number of cases have been treated with this procedure, this report should be viewed as preliminary in nature.

Prevention of cardiac disease by subcutaneous deferoxamine in patients with thalassemia major.

We examined the efficacy of long-term subcutaneous deferoxamine therapy in the prevention of iron-related cardiac disease in patients with thalassemia major who began treatment after the age of 10 years. Of 36 such patients without preexisting cardiac disease, 19 did not comply with the program of chelation therapy. Over the course of treatment (1977 to 1983) serum ferritin and aspartate aminotransferase levels fell in the compliant group, from mean values (+/- S.D.) of 4765 +/- 2610 to 2950 +/- 1850 ng per milliliter and 58.1 +/- 22 IU to 30 +/- 20 IU per liter, respectively (P less than 0.05), but rose in the noncompliant group, from 5000 +/- 2316 to 6040 +/- 2550 ng per milliliter and 56.6 +/- 20 to 90 +/- 35 IU per liter, respectively. Only one patient in the compliant group acquired cardiac disease and died of fulminant congestive heart failure. In contrast, 12 noncompliant patients acquired cardiac disease, and 7 died. In addition, the mean age of the compliant population (18.9 +/- 4.5 years) now approaches the mean age of acquisition of cardiac disease in the noncompliant group (19 +/- 4.3). These data demonstrate that compliance with treatment with deferoxamine may protect patients from cardiac disease induced by iron overload.

Intensive plasma exchange in small and critically ill pediatric patients: techniques and clinical outcome.

Standard apheresis techniques require modification of use in children, particularly those with serious concurrent medical problems, as they are prone to apheresis-induced disturbances of volume, metabolism, and coagulation. We report 112 plasma exchanges (TPE) on 11 children, 9 of whom weighed less than 20 kg and 7 of whom were critically ill. All were treated on continuous flow apparatus; seven on centrifugal systems (CS), two on a membrane filtration system (MFS), and two on both. Perturbations of blood and red blood cell (RBC) volume were prevented by priming the extracorporeal circuits with a red cell saline mixture having an hematocrit equal to or greater than the patient's hematocrit. Priming volume and minimal flow rates were 170 ml and 40 cc/min (MFS) and 350 ml and 10 cc/min (CS). TPE dose varied from 1.3 to 3 plasma volumes. Immunoglobulins fell by the following amounts: IgG 43.7%, IgA 36.7%, and IgM 41% per plasma volume. Platelets fell by 20-90% (CS) and 5-7% (MFS). Vascular access was obtained by various means including Thomas shunts, dialysis catheters, and standard 16-19 gauge butterflies and angiocaths. Bleeding in patients with coagulopathies was prevented by using repeated small boluses of heparin to maintain a clotting time of 2.5-3 minutes. Morbidity from TPE was limited to citrate toxicity (2 patients) and transient pulmonary edema (1 patient). Treatment outcome was successful in 8 out of 11 patients. We have shown that if PEX is otherwise indicated, it should not be withheld solely for patient size or the complexity of concurrent medical problems.

Intensive immunosuppression in progressive multiple sclerosis. A randomized, three-arm study of high-dose intravenous cyclophosphamide, plasma exchange, and ACTH.

Fifty-eight patients with severe, progressive multiple sclerosis were prospectively randomized to one of three treatments: 20 received intravenous ACTH, 20 received high-dose intravenous cyclophosphamide plus ACTH, and 18 were placed on a regimen consisting of plasma exchange, low-dose oral cyclophosphamide, and ACTH. The three groups were similar in age, sex, duration and type of disease, and degree of disability. Before treatment and six months and one year after treatment, a disability-status score, ambulation index, and functional-status score were determined, and a quantitative neurologic examination was performed. In the ACTH group, the number of patients stabilized or improved was 8 of 20 at six months and 4 of 20 at one year; in the cyclophosphamide-ACTH group, 18 of 20 at six months and 16 of 20 at one year; and in the plasma exchange group, 11 of 18 at six months and 9 of 18 at one year. High-dose cyclophosphamide plus ACTH was most effective in halting progression of the disease at both 6 and 12 months (at 12 months, cyclophosphamide-ACTH vs. ACTH, P = 0.0004; cyclophosphamide-ACTH vs. plasma exchange, P = 0.087). Thus, progressive multiple sclerosis may be stabilized by short-term, intensive immunosuppression with cyclophosphamide plus ACTH.

Pharmacokinetics of continuous intravenous and subcutaneous infusions of cytosine arabinoside.

The pharmacokinetics of continuous subcutaneous cytosine arabinoside (ara-C) infusions were compared with continuous intravenous infusions. Steady-state serum ara-C levels and myelosuppression were similar with both routes of administration. CSF/serum ara-C ratios ranged from 0.14 to 0.91 (mean, 0.58). Continuous subcutaneous ara-C infusions were a convenient and reliable alternative to intravenous infusions.

Neocytes and neocyte-gerocyte exchange.

Patients requiring chronic transfusions deposit large quantities of iron throughout their reticuloendothelial and parenchymal systems. Diabetes mellitus, hepatic fibrosis, and cardiomyopathy are the ultimate pathologic manifestations. One mechanism for decreasing the rate of iron loading would be to transfuse only the youngest cohort of cells from a donor (neocytes). At the same time the patient's oldest red cells are being removed (neocyte-gerocyte exchange). In this manuscript we describe techniques presently available for such a procedure.

The nonspecificity of the thyroid halo sign.

In a series of 28 patients with solitary solid thyroid masses, 10 of the patients had a mass surrounded by a rim of decreased echoes or by an echo-free rim, previously termed the halo sign. Eight of these lesions were benign, being either adenomas or benign nodules; however, two halos were also demonstrated surrounding proven carcinomas. The presence of the halo in both benign and malignant disease is illustrated, and the possibility of pericapsular inflammatory infiltrate as its underlying anatomic correlate is suggested.