Predicting verbal memory decline following anterior temporal lobectomy (ATL).

OBJECTIVE: To develop a multivariate risk factor model for predicting postoperative verbal memory decline in an individual patient following dominant or nondominant anterior temporal lobectomy (ATL). METHODS: The authors studied 132 consecutive ATL patients who 1). were older than 16 years at surgery, 2). had estimated preoperative Full Scale IQ score of >69, 3) had unilateral language dominance based on the intracarotid amobarbital procedure (IAP), and 4) underwent neuropsychological testing at baseline and >or=6 months postoperatively (mean 1.2 years). Five potential risk factors for postoperative verbal memory decline were selected a priori that reflect the functional adequacy of the to-be-resected temporal lobe. These were 1). resection in the dominant hemisphere, 2). MRI findings other than exclusively unilateral mesial temporal sclerosis, intact preoperative 3). immediate and 4). delayed verbal memory function, and 5). intact IAP memory performance following injection contralateral to the seizure focus. Verbal memory decline was defined using two verbal memory tests and published reliable change indices. RESULTS: Thirty-eight percent of the sample declined reliably on one or both verbal memory measures. Logistic regression analysis demonstrated that all five risk factors were significantly and independently associated with outcome, with side of surgery having the strongest association (p < 0.0001) and preoperative immediate verbal memory the weakest (p < 0.05). CONCLUSIONS: An individual patient's risk for postoperative verbal memory decline following dominant or nondominant ATL can be predicted using clinical data routinely available preoperatively (side of surgery, qualitative MRI, baseline memory testing, IAP performance). This information may be useful for preoperative patient counseling.

A constant compliance force modulation technique for scanning force microscopy (SFM) imaging of polymer surface elasticity.

A new method of force modulation scanning force microscopy (SFM) imaging based on a constant compliance feedback loop is presented. The feedback adjusts the loading force applied by the SFM tip to the surface in order to maintain a constant compliance beneath the tip. The new method, constant compliance force modulation (CCFM), has the advantage of being able to quantify the loading force exerted by the tip onto the sample surface and thus to estimate the elastic modulus of the material probed by the SFM tip. Once the elastic modulus of one region is known, the elastic moduli of other surface regions can be estimated from the spatial map of loading forces using the Hertz model of deformation. Force vs. displacement measurements made on one surface locality could also be used to estimate the local modulus. Several model surfaces, including a rubber-toughened epoxy polymer blend which showed clearly resolved compliant rubber phases within the harder epoxy matrix, were analyzed with the CCFM technique to illustrate the method's application.

The effects of human hippocampal resection on the serial position curve.

The purpose of this study was to examine the contribution of the human hippocampal formation to the classic serial position curve. Seventy-seven patients who underwent anterior temporal lobectomy (ATL) (47 left, 30 right) were administered a list learning task before and after surgery, and changes in the serial position curve were examined. Forty nonsurgical patients with complex partial seizures were tested at comparable intervals and served as controls. Changes in the serial position curve were seen only after left ATL, and almost exclusively among patients without hippocampal sclerosis. Patients without left hippocampal sclerosis, and who therefore underwent resection of hippocampus that was to a considerable degree structurally (and presumably functionally) intact, showed significant declines in recall from the primacy and middle portions of the list compared to all other groups. There was no change in the recency portion of the list. Patients with left hippocampal sclerosis showed only a modest decline in recall from the middle region compared only to the control group, and the right ATL groups did not show any significant changes in serial position recall. These findings demonstrate the contribution of the left hippocampus to those discrete portions of the serial position curve which rely on secondary memory, and have implications for assessing the effects of ATL on memory function.

The hawaii to tahiti shuttle experiment.

The Shuttle Experiment conducted between Hawaii and Tahiti from January 1979 to June 1980 was designed to observe the changing equatorial ocean structure and circulation, to study the variations and interactions of the four major equatorial ocean currents, and to develop a scientific basis for their monitoring by simple observations of thermal structure and sea level. Preliminary analyses of the results show that the equatorial thermal structure remains intact during a normal year and that only the positions and intensities of the currents are subject to change. The water transport of the equatorial undercurrent varied from 25 x 10(6) cubic meters per second in January to 51 x 10(6) cubic meters per second in July, but also exhibited strong short-term pulsations. The equatorial surface flow responded strongly to the winds at periods of 1 month and longer. An array of drifter buoys in the equatoral countercurrent was subject to very little dispersion while traveling over 4500 kilometers in 4 months. Low-frequency fluctuations in the North Equatorial Countercurrent can be monitored by means of the difference in sea level between Fanning and Majuro.

Predicting and observing el nino.

In October 1974 the occurrence of a weak El Niño event was predicted for early 1975 on the basis of the southern oscillation index. An expedition was organized to observe the event in the waters off Peru and Ecuador during two cruises in order to study its occurrence and its development with time. During the first cruise a massive transgression of warm low salinity water across the equator to 4 degrees S was observed, as well as a depression of the thermocline along the equator and off the coast of South America, indicating the start of El Niño development. During the second cruise the oceanographic situation had changed and conditions were returning to normal.