Motor and non-motor sequence learning in children and adolescents with cerebellar damage.

Cerebellar involvement in motor and non-motor sequence learning was examined with serial reaction time tasks (SRT). Our sample consisted of 8 children and adolescents who had undergone surgical removal of a benign posterior fossa tumor (PFT) during childhood. None of them had undergone chemotherapy or cranial radiation therapy (CRT). Ages ranged from 1-11 years at surgery and 9-17 years at testing. The children were tested not earlier than 2.5 years after surgery (M = 5.9 years), enabling brain plasticity and recovery of functions. Their performance was compared with a matched control sample. The PFT group was not impaired in the implicit learning of sequences, as reflected in their performance in blocks with a repeated sequence, both before and after a random block. However, in the perceptual task, their performance deteriorated more than that of the control group when a random block was introduced, suggesting that it was more difficult for the patients to respond flexibly or change their response set when encountering changing task demands. These results are in line with another study by our group on task switching with the same patients.     

Decision-making process in abdominal surgery in the geriatric patient

The high rates of abdominal disorders in a growing population of geriatric patients and the greater willingness of the surgeon to cope with major problems in the elderly are factors contributing to a steady increase in abdominal procedures in this group. Four hundred consecutive major abdominal surgical procedures in patients over 70 years of age were submitted for computer analysis, the purpose of which was to determine the principal factors affecting mortality and morbidity. The etiological profile of abdominal surgery in the elderly was characterized by a high percentage of procedures related to the biliary tract, with the second largest group being those for intestinal obstruction due to benign and malignant conditions. The decision-making process in geriatric surgery is of great importance, requiring consideration of ethical, medico-legal and economic factors in addition to the purely medical ones. Analysis of data presented in this series leads to the following conclusions:

1. There is a declining mortality rate in all elective operations in the elderly, in the absence of widespread malignancy.
2. Timing is all important in abdominal emergencies in the elderly, and early operations are usually more successful than either immediate or delayed operations.
3. Definitive procedures are sometimes both safer and more cost effective than minimal procedures performed under such circumstances.
4. The principal factors leading to high mortality rates are the presence of malignancy, generalized peritonitis, and moderate-to-severe involvement of life-support systems.

     

VISUAL PATHWAY TUMORS AND HYDROCEPHALUS

The authors evaluated the impact of hydrocephalus on the clinical picture of children with visua pathway tumor (VPT) with or without neurofibromatosis (NF).Charts of children with VPT treated in the authors' center since 1985 were retrospectively reviewed, and those with hydrocephalus were selected and summarized. Thirty-five children with VPT were found, of whom 20 had NF.Hydrocephalus was found in 4 children with NF (20% ) and in 5 without NF (33.3% ). In 6 ofthechildren, ventricular dilatation with signs of acute increased intracranial pressure already existed at the time of diagnosis and the hydrocephalus was shunted at this time. In the other 3 children, all with NF,the hydrocephalus resulted from slowly developing aqueductal stenosis, leading in 2 to severe visual acuity deterioration. The results suggest that in children with VPT and NF, hydrocephalus, and especially hydrocephalus resulting from aqueductal stenosis, is more frequent than in the general population of NF patients, and less frequent than in VPT patients without NF. The possibility of the indolent development of hydrocephalus should be borne in mind while following children with NF. The optic nerve, when already involved with a glioma, is more vulnerable to increased pressure. Thus, in children with VPT and NF, any ventricular dilatation should lead to a consideration of early shunting.     

Stone Age hut in Israel yields world's oldest evidence of bedding

The earliest archaeological remains of dwelling huts built by Homo sapiens were found in various European Upper Paleolithic open-air camps. Although floors of huts were found in a small number of cases, modern organization of the home space that includes defined resting areas and bedding remains was not discovered. We report here the earliest in situ bedding exposed on a brush hut floor. It has recently been found at the previously submerged, excellently preserved 23,000-year-old fisher-hunter-gatherers' camp of Ohalo II, situated in Israel on the shore of the Sea of Galilee. The grass bedding consists of bunches of partially charred Puccinellia confer convoluta stems and leaves, covered by a thin compact layer of clay. It is arranged in a repeated pattern, on the floor, around a central hearth. This study describes the bedding in its original context on a well preserved intentionally constructed floor. It also reconstructs on the basis of direct evidence (combined with ethnographic analogies) the Upper Paleolithic hut as a house with three major components: a hearth, specific working locales, and a comfortable sleeping area near the walls.     

Three-dimensional imaging improves surgical skill performance in a laparoscopic test model for both experienced and novice laparoscopic surgeons

Study objective

The objective of this study was to evaluate and compare the impact of three-dimensional (3D) imaging system on the performance of basic laparoscopic tasks in a test model by novice and experienced surgeons.

Design

Three tasks were performed in a test model by 30 surgeons, 15 experienced surgeons, and 15 with minimal laparoscopic experience. The tasks were performed using 2D and 3D vision systems.

Design classification

Canadian Task Force II-1.

Subjects

Fifteen experienced laparoscopic surgeons and fifteen novices with minimal laparoscopic experience.

Measurements

Performance times were recorded using both two-dimensional and 3D imaging system for each task.

Main results

Performance time for all skills was significantly (P < 0.02) shorter when using 3D imaging system. Performance times were reduced by 18–31 % using 3D imaging for all participants. Experienced surgeons performed the tasks faster and showed similar improvement while using 3D imaging system.

Conclusion

3D vision systems allow for significant improvement in performance times of basic laparoscopic tasks in a test model for both inexperienced and advanced laparoscopic surgeons. Experienced surgeons benefit as much as novices from 3D imaging system. This benefit should be weighed against the disadvantages of the 3D vision systems, mainly cost, decreased light, eye strain, headaches, and shorter focal lengths.     

Detachment of subfoveal choroidal neovascularization in age-related macular degeneration

PURPOSE: To report the entity of partial detachment and folding of subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (ARMD). DESIGN: Interventional case reports. METHODS: Review of the features of CNV detachment in two patients with CNV due to ARMD by contact lens slit-lamp biomicroscopy, fluorescein angiography, optical coherence tomography, and three-dimensional confocal scanning laser indocyanine green (ICG) angiography. RESULTS: One patient out of approximately 300 (0.5%) ARMD patients treated by photodynamic therapy (PDT) developed partial CNV detachment and folding 6 weeks after the second PDT treatment. Another patient out of approximately 100 (1.0%) ARMD patients treated by transpupillary thermotherapy (TTT) developed partial CNV detachment and folding 6 weeks after the second TTT treatment. The CNVs were large (2,500 microm to 4,500 microm) and located between the retina and the retinal pigment epithelium. In each, these findings were clearly visualized by slit-lamp biomicroscopy. Fluorescein angiography demonstrated an associated retinal pigment epithelium tear in one patient. Optical coherence tomography showed distinctive features and confocal scanning laser ICG further delineated the detached folded CNV. The best-corrected visual acuity improved in one patient from 20/80 to 20/40 and in the other from counting fingers at 6 feet to 20/200 after the CNV detachment. CONCLUSIONS: Partial CNV detachment and folding represent a unique, not previously reported, and possibly favorable outcome of PDT and TTT. The low energy and selectivity of these treatments may explain this phenomenon.     

Retinal nerve fiber layer thinning in Parkinson disease

Retinal dopamine loss in Parkinson disease (PD) is reflected by visual neurophysiological dysfunction. We measured the thickness of the circumpapillary retinal nerve fiber layer (RNFL) in PD patients using optical coherence tomography. The thickness in the inferior quadrant of PD patients (147 +/- 20 microns) was significantly thinner than that of controls (173 +/- 12 microns; p=0.002), while the inferotemporal area was the thinnest (146 +/- 24 vs. 191 +/- 21 microns; p=0.0003). The results show significant loss of RNFL thickness in PD at specific sites.