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PubMed2000

Neuropsychological functioning in a patient with essential tremor with and without bilateral VIM stimulation.

The effects of deep brain stimulation on motor functions, cognitive abilities, and mood were assessed in an 80-year-old, right-handed male with a chronic history of essential tremor. Electrodes were implanted bilaterally in the ventral intermediate nucleus of the thalamus during a single operation. Upon evaluation at 3 months postsurgery, bilateral stimulation was associated with a clinically significant reduction in tremor ratings and improvement in manual dexterity. At that time, a battery of neuropsychological measures was administered with and without bilateral stimulation. The patient demonstrated comparable performances on measures of visuospatial perception, attention, mental tracking, verbal learning, and verbal recognition memory in both the "on" and "off" conditions. Without stimulation, the patient demonstrated declines of greater than 1 SD on measures of verbal fluency and verbal recall compared to when the stimulators were active. Responses to mood rating scales also indicated greater subjective distress without stimulation. Results are discussed in the context of previous studies of the effects of thalamic stimulation on neurocognitive functioning.

Aged↗
PubMed1998

Pattern of neuropsychological deficit at age five years following neonatal unilateral brain injury.

The pattern of language deficit following left-hemisphere brain injury and visual/spatial deficit following right-hemisphere injury in an adult or older child is well recognized, but has been inconsistently reported following presumed neonatal brain injury. Our prospective study of 24 children at age 5 with documented neonatal unilateral brain injury lends support to the theory of hemisphere specialization at the time of birth. Twelve children who had unilateral left-hemisphere lesion were compared to 12 children with unilateral right-hemisphere lesion of similar timing and severity. Relative visual/spatial deficit following right-hemisphere lesion and receptive language deficit following left-hemisphere lesion were identified. Lateralized measures of grip strength, fine motor speed, and fine motor dexterity were not significantly different between the groups for either hand in this nonhemiparetic study sample. Only one child with a left-hemisphere lesion was left-handed, and only one child (right-lesion) had a hemiparesis.

Brain Injuries↗
PubMed1993

A study on the neurobehavioral effects of occupational exposure to organic solvents in Korean workers.

In order to investigate the neurobehavioral effects in workers occupationally exposed to organic solvents in Korea using WHO neurobehavioral core test battery (NCTB), a cross-sectional study of 113 male car painters and printers and 81 controls was conducted. Among the seven tests of the NCTB, only four tests--simple reaction time, Santa Ana dexterity, digit symbol, and Benton visual retention tests--were administered to the subjects because of time limitations. Painters and printers were exposed mainly to toluene, xylenes, and methyl ethyl ketone and often to solvent mixtures. The range of the solvent exposure level was 0.10-2.29 of hygienic effect. Poorer performance of Benton visual retention in the exposed group when compared to the control group was found after controlling confounders. No exposure-dependent effect was found. Further investigation with a matched control group regarding confounding factors is required for conclusive results.

Adult↗
PubMed1998

Neurotoxic effects of low-level methylmercury contamination in the Amazonian Basin.

Many studies have demonstrated mercury contamination in the Amazonian ecosystem, particularly in fish, a dietary mainstay of populations in this region. The present study focused on potential health effects of this low-level methylmercury exposure. The study was carried out in a village on the Tapajós River, a tributary of the Amazon, on 91 adults inhabitants (15-81 years), whose hair mercury levels were inferior to 50 mu/g. Performance on a neurofunctional test battery and clinical manifestations of nervous system dysfunction were examined in relation to hair mercury concentrations. Near visual contrast sensitivity and manual dexterity, adjusted for age, decreased significantly with hair mercury levels (P < 0.05), while there was a tendency for muscular fatigue to increase and muscular strength to decrease in women. For the most part, clinical examinations were normal, however, hair mercury levels were significantly higher (P < 0.05) for persons who presented disorganized movements on an alternating movement task and for persons with restricted visual fields. These results suggest dose-dependent nervous system alterations at hair mercury levels below 50 micrograms/g, previously considered a threshold for clinical effects. The profile of dysfunction in this adult population is consistent with the current knowledge on methyl-mercury poisoning. The long-term implications of these findings are unknown and need to be addressed.

Adolescent↗
PubMed2002

A new skeleton of Theropithecus brumpti (Primates: Cercopithecidae) from Lomekwi, West Turkana, Kenya.

A relatively complete skeleton of the fossil papionin, Theropithecus brumpti, from the site of Lomekwi, west of Lake Turkana, Kenya, is here described. The specimen, KNM-WT 39368, was recovered at the site of LO 5 (3 degrees 51'N and 35 degrees 45'E), from sediments dated to approximately 3.3Ma. The skeleton is that of an old adult male and preserves a number of articulated elements, including most of the forelimbs and tail. The cranial morphology is that of a large, early T. brumpti, exhibiting a deep mandible with a deeply excavated mandibular corpus fossa, and mandibular alveoli and cheek teeth arrayed in a reversed Curve of Spee. The forelimb skeleton exhibits a unique mixture of characteristics generally associated with a terrestrial locomotor habitus, such as a narrow scapula and a highly stable elbow joint, combined with those more representative of habitual arborealists, such as muscle attachments reflecting a large rotator cuff musculature and a flexible shoulder joint. The forelimb of KNM-WT 39368 also presents several features, unique toTheropithecus, which represent adaptations for manual grasping and fine manipulation. These features include a large, retroflexed medial humeral epicondyle (to which large pronator, and carpal and digital flexor muscles attached) and proportions of the digital rays that denote capabilities for precise opposition between the thumb and index finger. Taken together, these features indicate that one of the earliest recognized representatives of Theropithecus exhibited the food harvesting and processing anatomy that distinguished the genus through time and that contributed to its success throughout the later Pliocene and Pleistocene. Based on the anatomy of KNM-WT 39368 and the known habitat preference of T. brumpti, the species is reconstructed as being a generally terrestrial but highly dexterous, very large-bodied, sexually dimorphic, and possibly folivorous papionin. T. brumpti was adapted for propulsive quadrupedal locomotion over generally even ground, and yet was highly adept at manual foraging. The estimate of 43.8kg body mass for KNM-WT 39368 renders unlikely the possibility that the species, or at least adult males of the species, were highly arboreal. T. brumpti, as represented by KNM-WT 39368, is seen as a large, colorfully decorated, and basically terrestrial papionin that was restricted to riverine forest habitats in the Lake Turkana Basin from the middle to latest Pliocene.

Animals↗
PubMed2005

Gaze-contingent soft tissue deformation tracking for minimally invasive robotic surgery.

The introduction of surgical robots in Minimally Invasive Surgery (MIS) has allowed enhanced manual dexterity through the use of microprocessor controlled mechanical wrists. Although fully autonomous robots are attractive, both ethical and legal barriers can prohibit their practical use in surgery. The purpose of this paper is to demonstrate that it is possible to use real-time binocular eye tracking for empowering robots with human vision by using knowledge acquired in situ. By utilizing the close relationship between the horizontal disparity and the depth perception varying with the viewing distance, it is possible to use ocular vergence for recovering 3D motion and deformation of the soft tissue during MIS procedures. Both phantom and in vivo experiments were carried out to assess the potential frequency limit of the system and its intrinsic depth recovery accuracy. The potential applications of the technique include motion stabilization and intra-operative planning in the presence of large tissue deformation.

Artificial Intelligence↗
PubMed1994

Therapy for progressive supranuclear palsy: past and future.

Dysfunction of multiple brain systems in progressive supranuclear palsy (PSP) has complicated attempts to treat the disease. Neurotransmitter replacement strategies targeting the dopaminergic, cholinergic, and serotonergic systems have been unsuccessful. In order to bypass the degenerated cortico-striato-pallidal loop, we administered the adrenergic agonist idazoxan (IDA) to treat PSP in two randomized double-blind, placebo controlled, crossover studies. Approximately one half of patients enrolled in these studies showed statistically significant improvement in balance and manual dexterity while taking IDA compared to placebo. These results suggest that new therapies that target structures outside of the basal ganglia may be useful for symptomatic treatment of PSP. Applying this strategy and developing treatments that arrest or reverse clinical deterioration in PSP will require improved understanding of the process underlying the illness.

Adrenergic alpha-Antagonists↗
PubMed1997

Can we define or measure manual skills in surgical training?

Neurosurgery requires manual dexterity. But should tests be devised to assess manual skills as part of a selection process for training or used as a means of determining surgical competence? The paper debates this fundamental question and proposes that manual skills for neurosurgical tasks need to be defined within the overall context of a recognised and fully assessed training programme. The importance of training as a means of transferring competence, part of which is manual skills, is emphasised. In conclusion the paper points out the inadequacy of solely measuring manual skills, were it possible, in assessing neurosurgical competence.

Clinical Competence↗
PubMed1991

Medical educational and functional determinants of employment after stroke.

To evaluate the medical educational and functional determinants of employment after stroke a total of 204 Patients were assessed for functional changes during rehabilitation and after one year. Additionally the educational and social background of each patient was documented. One year after discharge from the rehabilitation unit 11.3% of the patients worked full-time and 2.7% part time. Another 14.7% had the decision pension versus employment still pending and 0.5% were classified as unemployed. 70.8% received regular retirement plan payments or disability pensions. Generally a similar level of functional capabilities can be observed after one year for working and non-working patients except for manual dexterity. Early admission to rehabilitation (within the first 12 weeks) favours return to work. A high school degree qualifying for university entrance and a well paid and better qualified profession as well are correlated with a higher percentage of patients regaining their employment. An other determining factor of employment after CVA is the physical requirement of the former work. Most of the working patients (92%) had been either transferred onto a job suited for an handicapped people or their work plan had been restructured accordingly.

Cerebrovascular Disorders↗
PubMed1994

Intracavernous prostaglandin E1 in erectile dysfunction.

Prostaglandin E1 (PGE1) is a naturally occurring substance that is present in a variety of mammalian tissues, including the semen of fertile men. Its use in the diagnosis and treatment of erectile dysfunction has been extensively studied. In doses of 10-20 micrograms, PGE1 produces full erections in 70-80% of patients with erectile dysfunction. In diagnostic use PGE1 is employed as a simple office test and in conjunction with various hemodynamic tests. Self-injection of PGE1, either with the patient or his partner administering the injection, is a minimally invasive and effective treatment for erectile dysfunction in patients with organic or psychogenic erectile dysfunction. Its use is contraindicated in patients with sickle cell anemia, severe coagulopathy, schizophrenia or severe psychiatric disorder, poor manual dexterity, severe venous incompetence, or severe systemic disease. As calculated from data in the published literature, the most frequent side effects are pain at the injection site or during erection (occurring in 16.8% of patients), hematoma/ecchymosis (1.5% of patients), and prolonged erection/priapism (1.3% of patients). The potential for prolonged erection/priapism, the most serious side effect, can be minimized by careful titration of the dose and through patient education. Systemic side effects occur rarely during PGE1 use. During extended use, patients should be monitored for potential long-term side effects, such as fibrosis and angulation.

Alprostadil↗
PubMed1996

Elderly patients' problems with medication. An in-hospital and follow-up study.

OBJECTIVES: To examine medication problems during a stay in hospital and after discharge and to identify risk factors that contribute to poor compliance with medication a prospective observational study was carried out in an university-affiliated geriatric hospital and a patients' home. PATIENTS: One hundred and nineteen patients admitted from home to the geriatric hospital underwent a comprehensive geriatric assessment. They were also tested in opening and removing tablets from various common medicine containers. Drug prescriptions before, during and after the hospital stay were recorded. Medication use at home was observed by a member of a hospital-based home intervention team. The patients' reports of their drug therapy was compared with those by their family doctors. RESULTS: Of all tested patients 10.1% failed to open at least one container. This inability was associated with poor vision, impaired cognitive function and low manual dexterity. Compliance with prescribed medication was associated with cognitive function, ability to handle medication containers, number of prescribed drugs and recent changes in drug prescriptions. Of the patients only 39.5% had stable drug prescriptions during the 3-month study period. Doctor/patient agreement concerning drug therapy was low in all age groups. The agreement rate and patients' knowledge of their treatment was correlated with cognitive function and the number of prescribed drugs. CONCLUSION: Patients' ability to open and remove tablets from common commercial packages/containers should be tested routinely during a stay in hospital. Management of medication should be taught and supervised within the first few days after discharge from hospital.

Aged↗
PubMed1995

The role of the left somatosensory cortex in human hand movement.

Hemispheric dominance for motor control in the human brain is still unclear. Here we propose asymmetric sensorimotor integration during human hand movements. We investigated the dexterity of hand movements and related sensory functions in four right-handed patients with cerebrovascular lesions in the postcentral gyrus. To clarify the distributions of cortical damage, semiquantitative analysis of regional cerebral blood flow (rCBF) was performed using single photon emission computed tomography (SPECT), and a three-dimensional surface display was generated from SPECT. Scores on motor and sensory tasks and rCBF values in the patients were compared with those in control subjects. All patients presented with asymmetric clumsiness of complex finger movements, in association with impairments of combined sensations such as stereognosis. These findings were indicative of a disorder of sensory information processing necessary to guide the movements. Two patients with left hemispheric damage showed bilateral clumsy hands, predominating on the right side, while the other two patients with right hemispheric damage showed only a left clumsy hand. In agreement with asymmetric clumsiness, measurement of rCBF along with a three-dimensional surface display revealed cortical hypoperfused areas, mainly in the perirolandic cortices, comprising the primary motor and somatosensory cortices. Perirolandic cortical hypoperfusion was bilateral in the two patients with bilateral clumsy hands, but only on the right side in the other two patients with left clumsy hands. These results suggest a dominant role of the left somatosensory cortex in sensorimotor integration for complex finger movements of humans.

Aged↗
PubMed1994

A neural-network system for control of eye movements: basic mechanisms.

This paper presents a neural-network-based system that can generate and control movements of the eyes. It was inspired by a number of experimental observations on the saccadic and gaze systems of monkeys and cats. Because of the generality of the approach undertaken, the system can be regarded as a demonstration of how parallel distributed processing principles, namely learning and attractor dynamics, can be integrated with experimental findings, as well as a biologically inspired controller for a dexterous robotic orientation device. The system is composed of three parts: a dynamic motor map, a push-pull circuitry, and a plant. The dynamics of the motor map is generated by a multi-layer network that was trained to compute a bidimensional temporal-spatial transformation. Simulation results indicate (1) that the system is able to reproduce some of the properties observed in the biological system at the neural and movement levels and (2) that the dynamics of the motor map remains stereotyped even when the motor map is subject to abnormal stimulation patterns. The latter result emphasizes the role of the topographic projection that connects the motor map to the push-pull circuitry in determining the features of the resulting movements.

Animals↗
PubMed1979

The electroencephalogram (EEG) as a research tool in human behavior genetics: psychological examinations in healthy males with various inherited EEG variants. I. Rationale of the study. Material. Methods. Heritability of test parameters.

In the first section of this paper, various research designs in human behavior genetics are compared. In this context, the commonly used concept of biometric genetics is critically evaluated from the point of view of science theory. It is contrasted with the Mendelian gene concept, which, in principle, leads to a much deeper theoretical understanding by offering clues for basic mechanisms. To explore this advantage fully, a research strategy is needed that first looks for genetic variability in a physiological parameter of possible importance for human behavior and then tries to explore the influence of this parameter on the function of the human brain and on behavior. If possible, this genetic parameter should be selected in a way that inferences as to the mechanism of its influence on behavior become feasible. Such genetic variability is provided by the hereditary variants of the normal EEG discovered by earlier work (cf. Vogel, 1970). In the following section, a research program on 298 adult healthy males, most of them soldiers, with various inherited EEG variants is described. Apart from controls with inconspicuous EEGs, this material comprises probands with the following EEG variants: low-voltage (N); low-voltage borderline (NG); monotonous alpha-waves (R); occipital fast alpha-variants (BO); fronto-precentral beta-groups (BG), and diffuse beta-waves (BD). In addition to an EEG examination, the probands were examined with various test methods measuring intelligence (IST; LPS; Raven); working speed and concentration (d-2; KLT); personal attitudes (MMPI; 16PF; RKS); and sensory and motor abilities (flicker fusion; tachistoscopy; reaction time to optic, acoustic and combined stimuli; two-hand dexterity; pursuit rotor; tapping). In a supplementary twin study on 52 male adult twin pairs (26 MZ, 26 DZ), heritabilities were determined for the test scores included in the main study. For most test scores, heritabilities are relatively low; the data are compared with those from the literature. We conclude that the test methods utilized in the main study (on EEG variants) are expected to demonstrate at the most a small to moderate correlation of the EEGs with psychological phenotypes as defined by test examinations, even if a major part of the genetic variability underlying these phenotypes would be due to differences in brain physiology that could be revealed by EEG variation.

Adult↗
PubMed1979

The electroencephalogram (EEG) as a research tool in human behavior genetics: psychological examinations in healthy males with various inherited EEG variants. III. Interpretation of the results.

Interpretation of the results from psychological examinations of 298 probands with inherited EEG variants requires (1) critical evaluation of previous literature on psychological EEG correlates, (2) knowledge of the main concepts and experimental approaches for elucidating the basic mechanisms of EEG rhythms, (3) discussion of previous attempts to link psychological variation in human populations with corresponding variation in brain function, and (4) interpretation of results from considerations at these three levels with the data from our own study. At the first level (previous psychological studies), comparison with Schmettau's study proved to be especially revealing: Her conclusions about personality correlates with high alpha-index and with "flat" EEGs were very similar to ours with the monotonous alpha- (R) and low-voltage (N) EEGs, respectively. Her EEG type with high beta-index overlaps with our beta-diffuse (BD) type; a tendency to psychasthenia and low resistance to stress is less obvious in our group, but is expressed indirectly by reduced speed and accuracy in tests requiring attentiveness and persistence. The correlation between alpha-frequency and intelligence found in other studies was confirmed by the especially high intelligence scores of our group with occipital fast alpha-variants (BO). At the second and third levels of the discussion (EEG mechanisms; neurophysiological theories), the cooperation of cerebral cortex (EEG battery), thalamus (pacemaker), and ARAS (tonic arousal) is discussed, and the personality typologies of Eysenck and Claridge are mentioned. From this and other evidence, the following hypotheses are discussed: 1) The personality profiles of the R group are influenced by high activity and efficiency of the thalamic alpha-pacemaker(s), which leads to a high degree of modulation, selection, and amplification of afferent stimuli. 2) In the countertype of this EEG variant, the N EEG, a low modulation and amplification by the thalamic alpha-pacemaker is assumed. This leads to relatively low intensity of feeling and to low spontaneous activity, but to faster information processing. Combined with an increased level of tonic arousal in the ARAS, it may cause certain 'neurotic' complaints (our low-voltage borderline (NG) group). 3) The EEG with diffuse beta-waves (BD) is caused by a high level of tonic arousal in the ARAS, which tends to distrub the thalamocortical circuit. This leads to reduced stress resistance and to impairment of intellectual functions, especially space perception. Due to limited evidence, the next two hypotheses are advanced only tentatively: 4) alpha-rhythm with very high frequency 16--19 c/s) leads to improvement of information processing and, hence, to high intellectual performance and motor dexterity. 5) Probands with frontoprecentral beta-groups (BG) show no psychological signs of increased tonic arousal; therefore, these beta-groups are caused not by increased tonic arousal of the ARAS, but by a genetic variant of a thalamic subsystem.

Adult↗
PubMed1993

Surgical indication in children with congenital hemiparesis.

Nine children with perinatal occlusion of the middle cerebral artery, resulting in unilateral enlargement of one lateral cerebral ventricle associated with cortical atrophy and subcortical cavity formation, were operated on because of intractable epilepsy. All subjects exhibited mild to severe hemiparesis, localized in the right side of the body in six instances and in the left side in the three cases. All but one patient presented with some degree of psychomotor retardation. The surgical treatment consisted of the removal of the atrophic cerebral cortex. One child died after surgery because of disseminated intravascular coagulation. All the remaining eight children benefited from the operation, with a decrease in the hypertonia of the affected limbs and an improvement in dexterity and gait as well as in intellectual performance. Five patients could be considered seizure-free following the surgical treatment, and the remaining three experienced a significant reduction in the frequency of the seizures.

Atrophy↗
PubMed1980

Oral aluminum and neuropsychological functioning. A study of dialysis patients receiving aluminum hydroxide gels.

Nine dialysis patients with significantly increased serum-aluminum levels due to chronic ingestion of aluminum hydroxide gels and eleven dialysis patients with normal serum-aluminum levels were tested neuropsychologically for generalized functions (intelligence, reasoning, memory) and for more specific abilities (visual memory, verbal and reading fluency, manual dexterity). All tests did not reveal any significant difference in neurophyscholigical functioning between the two groups. This finding seems to indicate that oral aluminum is not neurotoxic for man, even under circumstances of renal failure. This contradicts the idea that oral aluminum plays a role in etiology of dialysis dementia. However, the possibility cannot be excluded that aluminum overload in the present sample was not sufficient to induce changes in CNS functioning. Thus, until the importance of oral aluminum has been decided, it seems wise to keep all sorces of aluminum overload as low as possible.

Aluminum↗
PubMed1989

Amantadine sulphate in treating Parkinson's disease: clinical effects, psychometric tests and serum concentrations.

Intravenous administration of amantadine has been shown to be a quick-acting and highly effective method of treating patients with Parkinson's disease. The duration of this therapeutic effect during long-term oral treatment has, however, remained controversial. Therefore, the effect of intravenous treatment was compared with long-term oral treatment over a period of 6 months. Clinical scores and psychometrically determined dexterity improved significantly during 10-day infusion therapy (200 mg amantadine sulphate/day). This improvement was successfully maintained by oral treatment (600 mg/day). A decrease in effectiveness was not observed. Reaction times were within the normal range for the age group involved and did not change significantly during the course of the study. Amantadine serum concentration during the infusion period ranged between 500 and 1000 micrograms/l and produced values nearly half as high as those obtained during oral treatment (600 mg/day). There was a constant relationship (quotient: 1.3) between serum and cerebrospinal fluid concentration. Considerable inter-individual variations were noted. A significant inter-individual correlation between serum concentration and clinical and psychological improvement was not discernible.

Administration, Oral↗