The data on arachnoid cysts in children (0-15 years) operated upon between 1980 and 1988 were analysed in a retrospective, co-operative study. The results from 285 patients indicate a predominance of these lesions in boys (64%) more than girls (36%) and a mean age of 6 years at onset of symptoms. Focal EEG patterns corresponding to the cyst's location were encountered in 32%. About 40% of all cysts were located along the midline, the sylvian fissure representing the predominant location. Open surgery, i.e. total excision or marsurpialization (together 43.3%), emerged as the first-choice surgical procedure. The type of surgery switched somewhat to shunting procedures in cases of lesions in deeper locations (22.8%). Morphological results on follow-up revealed a reduction of the size of the cyst in a significant majority (61%); in 18% the cyst had disappeared completely on CT scans. There was an obvious correlation between postoperative morphological findings and clinical outcome.

Objective: To evaluate a selective implantable drop foot stimulator (ActiGait) in terms of effect on walking and safety. Design: A phase II trial in which a consecutive sample of participants acted as their own controls. Subjects: People who had suffered a stroke at least 6 months prior to recruitment and had a drop-foot that affected walking were recruited from 3 rehabilitation centres in Denmark. Methods: Stimulators were implanted into all participants. Outcome measures were range of ankle dorsiflexion with stimulation and maximum walking speed and distance walked in 4 minutes. Measurements were applied before implantation, at 90 days and at a long-term follow-up assessment. Changes over time and with and without stimulation are reported. Safety was evaluated by nerve conduction velocity and adverse events. Results: Fifteen participants were implanted and 13 completed the trial. Long-term improvements were detected in walking speed and distance walked in 4 minutes when stimulated, and the orthotic effect of stimulation showed statistically significant improvement. The device did not compromise nerve conduction velocity and no serious device-related adverse events were reported. Technical problems were resolved by the long-term follow-up assessment at which further improvement in walking was observed. Conclusion: This trial has evaluated the safety and performance of the device, which was well accepted by patients and did not compromise safety.

A total of 911 Danish children under 15 years of age were treated for an intracranial tumour in the 25-five year period 1960-1984. All cases were followed up to the end of 1994 or to emigration or death if one of these came sooner. The mean annual incidence was 32.5 per million children with a slight increase over the 25 years. The male/female ratio was 1.15 and close to the M/F ratio for the entire Danish population of children. Of the tumours, 46% were located in the supratentorial and 54% in the infratentorial compartment, and 94% were verified histologically. In order of frequency the most common types were astrocytomas (all grades, 35%), medulloblastomas (20%), ependymomas (14%), and craniopharyngiomas (5%). Total removal of the tumour was performed in 277 and partial removal, including biopsy, in 490 children. In 57 patients a shunt operation only was performed, and 87 children did not have an operation or died before the correct diagnosis was established. Radiotherapy was administered in 55%. The outcome depended on extent of removal, radiation, location and histology of the tumour. Most (784 or 86%) of the children survived more than 1 month after diagnosis or operation, and 353 children (39% of the whole series, 47% of those alive more than 1 month after diagnosis) were alive at follow-up. Of the survivors 29% had a tumour in the supratentorial midline, 26% one in the lateral part of the supratentorial area, 31% a cerebellar tumour and 13% a IV ventricle tumour. It was possible for 66% of the survivors with supratentorial and 90% of those with infratentorial tumours to lead a normal life. The long-term prognosis was especially good for children with cerebellar and supratentorial astrocytomas and optic chiasma tumours. Children with juvenile cerebellar astrocytoma had the best prognosis: 90% were alive at the end of the follow-up period, as against 20% of those with medulloblastoma and 6% of those with glioblastoma. A comparison of the data from the present series and from a similar Danish series of intracranial tumours in 533 children seen in the years 1935-1959 shows no significant differences in location or histology, a slight increase in annual incidence, and improved survival rates during the 50 years in question.

A tetraplegic volunteer was implanted with percutaneous intramuscular electrodes in hand and forearm muscles. Furthermore, a sensory nerve cuff electrode was implanted on the volar digital nerve to the radial side of the index finger branching off the median nerve. In laboratory experiments a stimulation system was used to produce a lateral grasp (key grip) while the neural activity was recorded with the cuff electrode. The nerve signal contained information that could be used to detect the occurrence of slips and further to increase stimulation intensity to the thumb flexor/adductor muscles to stop the slip. Thereby the system provided a grasp that could catch an object if it started to slip due to, e.g., decreasing muscle force or changes in load forces tangential to the surface of the object. This method enabled an automatic adjustment of the stimulation intensity to the lowest possible level without loosing the grip and without any prior knowledge about the strength of the muscles and the weight and surface texture of the object. Index Terms-Functional electrical stimulation (FES), hand grasp, natural sensory feedback, nerve cuff electrode, neural prostheses I. INTRODUCTION M OTOR function of a paralyzed hand can be partially restored by means of functional electrical stimulation (FES) [1]-[3]. The present systems are feedforward-controlled, and the user relies on his/her experience and on visual feedback. When picking up an object, the user has to estimate the appropriate stimulation intensity, which produces enough force to hold the object. This is difficult and causes many patients to use excessive force [4]. Further, the system is not able to adapt to slow changes in force output of the stimulated muscles caused by, e.g., fatigue, electrode drift, and length-tension properties of the muscles at different hand orientations. To deal with these problems, it has been proposed to use force sensors, position sensors, or combinations thereof to provide closed-loop control of the grasp. This provides more linear control of grasp force and grasp opening [5]. Several investigators have looked into the possibilities of using artificial sensors for measurement of finger position and grasp force

In a well-defined area, The Kingdom of Denmark, 1076 patients with ruptured intracranial aneurysms were admitted to the six Danish neurosurgical departments in a prospective consecutive study in the 5-year period 1978-1983. Follow-up examinations were accomplished 3 months and 2 years after the admission. A total of 674 women and 402 men with a median age of 49 years were included in the study. The localisation of the ruptured aneurysms were: internal carotid artery 285, anterior communicating artery and horizontal part of anterior cerebral artery 383, middle cerebral artery 291, basilar and vertebral arteries 83 and peripheral or other localisation 34. A significantly better outcome was seen in cases with internal carotid aneurysms compared to other localisations. 670 patients underwent operation. A highly significantly better outcome was found in operated versus non-operated patients in comparable clinical conditions. The advantage of microneurosurgery was well documented. Patients with vasospasm had a significantly worse outcome. Within the first 2 weeks a daily rebleeding rate from 0.2% to 2.1% was observed, and patients who rebled had a significantly worse outcome compared to patients, who did not rebleed. The overall outcome at 2-year follow-up was: normal 27.5%, mild dementia 15.8%, severe dementia 9.9%, vegetative 1.3% and mortality 45.5%.