Biomedical subjects

A Bouma

Publications and source records attributed to A Bouma.

At least 73 records · Page 4Linked to original sources

PubMed1997

Effects of transcutaneous electrical nerve stimulation on memory and affective behavior in a stroke patient.

Although stroke is characterized by both a loss of mental and sensorimotor abilities, rehabilitation is particularly aimed at recovery from physical disabilities. In the case study reported in this article, it was hypothesized that a 30-min-a-day treatment with transcutaneous electrical nerve stimulation (TENS) might improve memory and affective behavior in a stroke patient. The hypothesis was derived from animal experimental studies in which peripheral stimulation resulted in activation of the hippocampus and hypothalamus. Although treatment could be started only 6 months after onset, the results suggest that TENS has a beneficial influence on visual short-term memory, verbal long-term memory, and verbal fluency. Moreover, [he patient's independent and social functioning in daily life improved. The conflicting effects of TENS on the patient's affective behavior are discussed.

Journal Article↗

PubMed1997

[Peripheral nerve stimulation in Alzheimer's disease].

The "use it or lose it' concept implies that stimulation of neurons might stop degenerative activities and initiate regenerative processes in aging and Alzheimer's disease (AD). Based on this concept, the effects of Transcutaneous Electrical Nerve Stimulation (TENS), tactile stimulation, and a combination of the two on memory and affective behaviour of AD patients were examined. The results suggest that, compared to AD patients of the control group, patients of the experimental group improved in visual short-term memory, verbal and visual long-term memory, and verbal fluency. Moreover, stimulated AD patients participated more independently in activities of daily life and their affective behaviour improved. As in those studies the therapist was present during the peripheral stimulation of the experimental group and the sham stimulation of the control group, interpersonal communication alone could not explain the treatment effects. However, a positive effect of the combination of TENS with personal interpersonal communication could not be excluded. Consequently, it was examined whether TENS, in the absence of the therapist, could also have a beneficial influence on the cognitive and behavioural functioning of AD patients. In addition, it was investigated whether TENS had a positive effect on the rest-activity rhythm of AD-patients. The results show that improvements in visual short- and long-term memory, verbal long-term memory, and verbal fluency are solely due to the peripheral stimulus itself. Furthermore, the independent and affective functioning of both the experimental and control group appeared to relatively improve by interpersonal communication. Moreover, the rest-activity rhythm of stimulated AD-patients improved. Peripheral nerve stimulation in AD might thus become a new treatment strategy to improve patients' quality of life.

Activities of Daily Living↗

PubMed1996

Transmission of two pseudorabies virus strains that differ in virulence and virus excretion in groups of vaccinated pigs.

OBJECTIVE: To determine whether 2 pseudorabies virus (PRV) strains that differ in virulence differ in transmission among vaccine strain 783-inoculated pigs. DESIGN: Three experiments were conducted, each with 2 groups of 10 pigs inoculated with the glycoprotein E-negative vaccine 783. In the first 2 experiments, half of one group was inoculated with the mildly virulent strain Sterksel, and half of the other group was inoculated with the virulent strain NIA-3. The remaining pigs were contact-exposed to the inoculated pigs. In the third experiment, 2 pigs in each group were inoculated with strain NIA-3, and the other 8 pigs in each group were contact-exposed to these 2 pigs. ANIMALS: Specific-pathogen-free pigs that were sero-negative for antibodies to PRV. PROCEDURE: Estimation of the transmission of virus in each group was based on a stochastic model, in which the observable variable was the number of contact infections. The sole parameter of the model was the reproduction ratio theta. A glycoprotein E ELISA was used to determine whether infection occurred. Virus excretion in the oropharyngeal fluid was determined by plaque assay to measure infectivity. RESULTS: Vaccinated pigs had a significant difference in virus excretion between the mildly virulent and virulent strains. Sterksel strain-inoculated pigs shed significantly more virus than did NIA-3 strain-inoculated pigs. Despite this difference in virus excretion, the 2 strains did not differ in transmission. CONCLUSIONS: Both PRV strains would be eliminated from a population of vaccine strain 783-inoculated pigs.

Analysis of Variance↗

PubMed1995

Sex and familial sinistrality differences in cognitive abilities.

Cognitive functioning was assessed in 69 left-handed males and females with a positive family history of left-handedness and in 77 left-handed and 55 right-handed males and females without familial left-handedness. Compared to females, males performed better on numerical reasoning and on two visuospatial tasks involving spatial manipulations (Figure Rotation and Surface Development). Within the group of left-handers, the multivariate effect for Familial Sinistrality was significant. Left-handers with familial left-handedness exhibited better scores on numerical reasoning, on verbal reasoning, and on two visuospatial tasks involving visual closure (Hidden Figures, Picture Completion) than did left-handers without left-handed relatives. The nonfamilial left-handers also exhibited lower scores on both inductive reasoning tasks when they were compared to their right-handed counterparts. The outcome runs contrary to the prevalent conclusion that left-handers with left-handed relatives are more likely to exhibit lower performances on visuospatial tasks than left-handers without such relatives.

Adolescent↗

PubMed1995

Effects of short-term transcutaneous electrical nerve stimulation on memory and affective behaviour in patients with probable Alzheimer's disease.

The present study investigated whether a 30-minute-a-day transcutaneous electrical nerve stimulation (short-term TENS) might improve disturbances in memory and affective behaviour in patients with probable Alzheimer's disease. The hypothesis was derived from former studies in which beneficial effects on memory and affective behaviour of Alzheimer patients were found after a daily application of 6-h TENS and a 30-min tactile stimulation. The present data reveal that short-term TENS improved some aspects of verbal and visual short-term and long-term memory. Moreover, patients who had undergone this treatment felt, e.g., less dejected, less gloomy, less irritable, more cheerful, more active, and more alert. They were also more interested in social contacts and participated more in daily activities. After a period of 6 weeks following treatment, the effects on memory as well as the improvements in affective behaviour partially remained.

Activities of Daily Living↗

PubMed1995

Experimental quantification of transmission of genetically engineered pseudorabies virus.

There is concern that live pseudorabies virus (PRV) vaccine or PRV vector vaccine strains may spread from vaccinated to unvaccinated pigs. Moreover, it is feared that recombining PRV vaccine strains with related vaccine or wild-type strains may lead to spread and survival of recombinant PRV. To learn more about to what extent different PRV vaccine strains could spread we used a previously described experimental model to study the transmission of intranasally inoculated PRV mutant strains under experimental conditions. We used PRV strains that lacked glycoprotein E (gE) or thymidine kinase (TK), and a PRV vector vaccine (gE-, TK-, gG-) that expresses the glycoprotein E1 (E1) of hog cholera virus. In addition, we investigated whether intranasally co-inoculated gE-negative and gE-positive PRV strains competed in transmission among pigs. The extent of transmission was estimated using the reproduction ratio R. This ratio has a threshold property; when R1, the infection can spread; when R < 1, the infection will disappear. We found that R for a gE-negative strain was 10.1, and R for a TK-negative strain was 5. Furthermore, the R for the vector vaccine (gE-, TK-, gG-) expressing E1 was 0.18, and did not differ significantly from the R for the control strain without E1. The R of gE-negative strain was significantly 1 (P = 0.0005). Co-inoculation with a gE-positive field strain did not prevent the transmission of a gE-negative strain. This study shows that a small-scale experiment can be used to estimate the transmission of genetically engineered organisms in their host species. The results of this study indicate that the deletion of gE alone or TK alone is not enough to prevent spread of PRV among susceptible pigs, and that transmission of gE-negative PRV is not firmly limited by co-presence of a gE-positive strain.

Administration, Intranasal↗

PubMed1995

The role of visual discrimination disorders and neglect in perceptual categorization deficits in right and left hemisphere damaged patients.

This study was designed to investigate the role of visual sensory deficits and neglect in perceptual categorization deficits in a group of 35 patients with unilateral cerebral lesions. From theoretical point of view, it was expected that right hemisphere lesions would play a critical role in eliciting perceptual categorization deficits which could not be accounted for by visual sensory deficits or neglect. The results revealed that perceptual categorization deficits were not confined to RHD patients, but they were also found in LHD patients. RHD patients were impaired regardless of the nature of the task (verbal vs. nonverbal), while LHD patients were impaired on nonverbal tasks, and in a lesser degree on verbal tasks. In both braindamaged groups, perceptual categorization deficits were highly associated with visual sensory deficits, however, perceptual categorization deficits were also found without impairments in the visual sensory system. Neglect to be less important determinant of perceptual categorization deficits. The present findings are discussed in the light of Warrington's model of object agnosia.

Adult↗

PubMed1994

Non-transmissible pseudorabies virus gp50 mutants: a new generation of safe live vaccines.

Envelope glycoprotein gp50 of pseudorabies virus (PRV) is essential for virus entry, but is not required for subsequent steps in the viral replication cycle. Phenotypically-complemented gp50 null mutants can infect cells and can spread, both in vitro and in vivo, by direct cell-to-cell transmission. However, progeny virions released by the infected cells are non-infectious because they lack gp50. Therefore, these viruses cannot be transmitted from infected animals to contact animals. These properties could make PRV gp50 null mutants attractive candidates as safe non-transmissible live vaccines. To establish whether phenotypically-complemented PRV gp50 null mutants and gp50 + gp63 double mutants could be used as live vaccines against Aujeszky's disease, the virulence and immunogenicity of these mutants were tested in pigs. Our results show that a gp50 null mutant has a greatly reduced virulence for pigs, and that pigs immunized with such a mutant were protected from clinical signs of Aujeszky's disease after a challenge inoculation with the virulent wild-type PRV strain NIA-3. PRV gp50 + gp63 deletion mutants proved to be non-virulent for pigs and were somewhat less immunogenic, since immunized animals showed some fever and growth retardation after challenge inoculation. Replication of wild-type challenge virus was significantly reduced, but could not completely be prevented, in pigs immunized with a gp50 null mutant, and was reduced less in pigs immunized with a gp50 + gp63 deletion mutant. Furthermore, infectious virus could not be recovered from oropharyngeal fluid or tissues from pigs inoculated with a gp50 null mutant or a gp50 + gp63 deletion mutant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Lexical decision performances in P-type dyslexic, L-type dyslexic, and normal reading boys.

Lexical decision performances in P-type dyslexic, L-type dyslexic, and normal reading boys were investigated using three-letter and four-letter words (familiar words) and nonwords presented in the central visual field. For words, P-type dyslexics displayed significantly longer latencies for four-letter than for three-letter word decisions, whereas L-type dyslexics and normal readers did not. For nonwords, all subject groups showed significantly larger mean latencies for four-letter than for three-letter nonword decisions. In general, the error data corresponded to the latency data. L-type dyslexics, however, made more errors during four-letter words than during three-letter words, although they had similar latencies in both conditions. The results are discussed with reference to the hypothesis that P-type dyslexics would use a sequential processing mode for reading familiar words, whereas L-type dyslexics would employ a parallel processing mode for reading familiar words.

Adolescent↗

PubMed1992

Influence of transcutaneous electrical nerve stimulation on memory in patients with dementia of the Alzheimer type.

This study examined the effect of transcutaneous electrical nerve stimulation (TENS) on memory in patients with dementia of the Alzheimer type. It was hypothesized that, in the early stage of the illness, electrical stimulation could activate the affected cortical regions by stimulating the neurotransmitter systems projecting to these areas. The results reveal that electrical stimulation improves the verbal long-term memory in these patients. Moreover, verbal fluency improves more in patients who received electrical stimulation than in patients who received control treatment. However, electrical stimulation does not influence the visual long-term memory of the patients, nor does it affect their verbal and nonverbal short-term memory. Underlying theoretical mechanisms are discussed.

Afferent Pathways↗

PubMed1992

Grade-related changes in event-related potentials (ERPs) in primary school children: differences between two reading tasks.

Event-related potentials (ERPs) were recorded from the left and right temporal and parietal sites during word reading in a group of children who were followed over three consecutive years, starting at Grade 1. The first task required the child to read repeatedly presented words; the second task consisted of a series of different words, with each word being presented only once. All ERP components showed changes in amplitude as a function of grade: P240, N530, the parietal N150, and SW all decreased, whereas the temporal N360 and SW both increased. In addition, SW changed from no asymmetry to larger positivity over the right site, whereas N360 changed from symmetric amplitudes to larger amplitudes over the left hemisphere with grade. Single word presentations were associated with smaller SW activity and larger N530 and N360 amplitudes than were repeated word presentations. It was also found that proficient readers showed larger SW and N360 asymmetries and shorter vocal response times than did less proficient readers. In addition, a positive relationship was found between reading performance and ERP amplitudes over the left temporal hemisphere at Grades 2 and 3, particularly in the single word reading task. The results are discussed in terms of age-related changes in right and left hemisphere functions involved in learning to read.

Attention↗

PubMed1990

Mental rotation of laterally presented random shapes in males and females.

Eighteen right-handed subjects (9 males, 9 female) were to decide if laterally presented random shapes were identical or a mirror image of a centrally presented standard shape. The lateral shapes were rotated over 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, or 300 degrees. For unrotated (0 degrees) mirror image stimuli, females showed a significant right visual-field advantage, whereas males showed no significant hemifield effect. The rate of rotation was equivalent for both sexes. Field of presentation did not affect the rotation rate either. The present results support a growing number of findings that indicate that the interpretation of mental rotation as a typical right-hemispheric spatial-processing task is questionable.

Adolescent↗

PubMed1990

Selective activation effects of concurrent verbal and spatial memory loads in left-handed and right-handed adults.

Thirty-two left-handed subjects, divided into four groups according to sex and familial sinistrality, and 16 right-handed subjects without familial sinistrality (8 male, 8 female) participated in a tachistoscopic unilateral letter-identification task with concurrent verbal- and spatial-memory loads. Across groups, a significant right visual field advantage for letter-identification was found. In the majority of both left-handed and right-handed subjects, the concurrent verbal-memory load resulted in a selective activation, with the right visual field performance showing improvement. However, the group of left-handed males with a positive family history of sinistrality gave less evidence of selective left-hemispheric activation as a consequence of the verbal-memory load. The concurrent spatial-memory load did not result in a consistent pattern of selective activation.

Adolescent↗

PubMed1990

Familial resemblance for cognitive abilities in families with P-type dyslexic, L-type dyslexic, or normal reading boys.

P-type dyslexic, L-type dyslexic, and normal reading boys, and their parents were administered a number of cognitive tasks. The P- and L-type dyslexic boys showed impaired performances on tasks representing a verbal/memory dimension. In addition, L-type dyslexics performed worse on a figure-rotation task, a result that supported the notion of a visuospatial deficit in this type of reading disturbance. The parents of P- and L-type dyslexics exhibited lowered performances on verbal/memory tasks, but they showed no evidence of impaired visuospatial functioning. Indices of familial resemblance revealed differential familial resemblances in the three types of families. In the families of P-type dyslexics, a high father-son effect was found for the visuospatial dimension. In the families of L-type dyslexics, moderately high single-parent/child effects were found for both fathers and mothers and for both the verbal/memory dimension and the visuospatial dimension. In the families of normal readers, only small single-parent/child effects were found.

Aptitude↗

PubMed1989

Event-related potentials during word-reading and figure-matching in left-handed and right-handed males and females.

In two experiments, event-related potentials at left and right occipital, parietal, and temporal sites were studied in 16 left-handers (8 male, 8 female) and 16 right-handers (8 male, 8 female). Subjects displayed extreme handedness, had a normal writing hand position, reported no left-handed relatives, and reported no perinatal traumata. In Experiment 1, centrally presented words had to be read, and nonverbal stimuli had to be matched. Condition-dependent asymmetries were found for P340 and SW components. Word-reading elicited a N500 component, whereas figure-matching did not. In Experiment 2, words presented to either the left or right visual field had to be read. It was found that N160 measures were larger, and P240, P400, and SW measures were smaller to words presented in the contralateral visual field compared to words in the ipsilateral field. Sex affected these pathway effects. In both experiments, hand preference did not significantly influence the ERP results.

Adult↗

PubMed1988

The development of lateral event-related potentials (ERPs) related to word naming: a four year longitudinal study.

Event-related potentials (ERPs) were recorded from the left and right temporal and parietal sites during a word naming task. Subjects were a group of children that were followed over four consecutive years starting at Kindergarten. ERP waveforms contained a sequence of positive and negative components (N150, P240, N360, N530 and SW). All components, except N150, showed changes in amplitude as a function of age, whereas SW, N360 and N150 also changed in hemispheric distribution. In addition, a relationship was found between reading performance and ERP amplitudes over the right parietal hemisphere in young children, and over the left temporal hemisphere in older children. Proficient readers showed larger (more negative) parietal N530 amplitudes than less proficient readers, especially when stimuli were degraded words. The results are discussed in terms of age-related changes in right and left hemisphere functions involved in early and advanced stages of reading, that might possibly be related to visual word recognition.

Aging↗

PubMed1988

Different mechanisms of ipsilateral and contralateral ear extinction in aphasic patients.

Dichotic listening performance was studied in 35 aphasic patients with unilateral brain lesions. Within this group, 30 patients exhibited an abnormal ear discrepancy: 20 patients showed a left-ear advantage (right-ear extinction), and 10 patients showed a right-ear advantage (left-ear extinction). All subjects were given a number of verbal tasks in order to evaluate several aspects of their linguistic abilities. For the left-ear advantage group, verbal scores were positively related to left-ear scores, but not to right-ear scores. For the right-ear advantage group, verbal scores were positively related to both left- and right-ear scores. The present results lend partial support for the prediction that right-ear extinction is associated with damage to the temporal lobe involving the geniculo-temporal system. No support was found for the prediction that left-ear extinction is associated with lesions placed in the deep structures of the parietal or parieto-occipital lobe involving the corpus callosum system. Our data indicate that the initial severity of brain injury is a critical factor in determining the direction of ear extinction, the lesions being larger in the left-ear advantage group. Results are discussed in relationship to other explanations of ipsilateral and contralateral extinction in aphasic patients.

Adult↗

PubMed1988

Cerebral organization of verbal and motor functions in left-handed and right-handed adults: effects of concurrent verbal tasks on unimanual tapping performance.

Two experiments were conducted to study the interference effects of different concurrent verbal tasks on unimanual single-finger tapping and unimanual sequential finger tapping. Experiment 1 involved 24 right-handed university students. In the dual-task conditions, right-handers showed a greater right-hand than left-hand performance reduction for single-finger tapping, and an equal right-hand and left-hand reduction for sequential tapping. Experiment 2 involved 60 left-handed university students, divided into four groups according to familial sinistrality and writing hand posture. In the dual-task conditions, left-handers showed a greater left-hand than right-hand performance reduction for single-finger tapping, and an equal left-hand and right-hand reduction for sequential finger tapping. A dichotic listening task revealed a left hemispheric dominance for auditory linguistic functioning in most of the left-handers. Familial sinistrality and hand posture, on the whole, did not influence tapping performances. However, these factors influenced the ear asymmetries on the dichotic listening task. It is speculated that, with single-finger tapping, interference only takes place beyond the point of language motor programming, that is to say, at the motor areas and the supplementary motor areas of the cortex.

Adolescent↗