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W Hartje

Publications and source records attributed to W Hartje.

At least 19 recordsLinked to original sources
PubMed2001

The bilateral effect: callosal inhibition or intrahemispheric competition?

The magnification of visual field asymmetry observed with bilateral compared to unilateral tachistoscopic presentation of homologous stimuli (bilateral effect) can be explained by two hypothetical processes: homologous activation with subsequent inhibition of callosal information transfer or intrahemispheric competition for processing resources. A lexical decision task with unilateral and bilateral stimulation and response with the right or left hand was used in an attempt to decide between these hypotheses. Analysis of response time data revealed a bilateral effect, superimposed on a right visual field advantage, and no interaction between visual field and response hand. Results are consistent with the hypothesis of intrahemispheric competition in the left hemisphere.

Adult↗
PubMed1998

[Evaluating driving ability after brain damage. Neuropsychological diagnosis and driving test].

The study examined the validity of psychometric measures for the assessment of driving ability in brain-damaged subjects. 116 patients with brain damage mainly of vascular and traumatic origin underwent extensive neuropsychological examinations emphasizing attentional performance and visual perceptual speed and participated in a comprehensive on-road driving test. Only 58% of the patients passed the driving test. Attempts to predict the outcome of the driving test by discriminant analysis or cut-off procedures based on neuropsychological and/or other subject-related data yielded a maximum of 73% correct predictions. In view of the frequent impairment in driving ability after brain damage and in view of the failure to reliably predict driving ability from psychometric test results, it is recommended that in each case an on-road driving test is given.

Adult↗
PubMed1998

Hemispheric dominance in the processing of J.S. Bach fugues: a transcranial Doppler sonography (TCD) study with musicians.

Although the majority of studies on musical processing in musicians observed a left hemisphere dominance which has usually been explained by a proficient analytical strategy used by these subjects, the findings are still inconsistent. Changes in hemispheric activity induced by listening to music (J. S. Bach fugues) and by recognizing the repetitions of the fugue theme were examined, using the technique of bilateral transcranial Doppler sonography (TCD) of the left and right middle cerebral artery (MCA). Subjects were 32 right-handed musicians, half of whom were members of an orchestra or members of a choir. The fugues were presented in two versions: a-cappella and instrumental. During passive listening to the a-cappella version, a weak left-dominant asymmetry of blood flow acceleration was observed, while there was no hemispheric asymmetry during listening to the instrumental version. During the task of fugue theme recognition, a highly significant asymmetry in favour of the right MCA was observed with both versions. It is concluded that when the processing of complex musical material has to be based on the analysis of melodic contour features and calls for working memory capacities a right hemisphere dominance is observed even in musically sophisticated subjects.

Adult↗
PubMed1997

Hemispheric asymmetry in the recognition of emotional attitude conveyed by facial expression, prosody and propositional speech.

In this study 27 patients with right hemisphere lesions, 25 patients with left hemisphere lesions and 26 normal control subjects were investigated for unimodal and simultaneous multimodal recognition of emotional attitude. All subjects were shown 330 videotaped items of 4 seconds duration, each of which was to be judged in terms of facial expression, emotional prosody and the emotional meaning of the underlying spoken sentence. In a preceding experiment comparable unimodal emotional stimuli were applied. The results suggest (a) right hemisphere superiority for recognition of emotions conveyed by facial and prosodic information, (b) a right hemisphere dominance for the recognition of fear and (c) no significant enhancement of right hemisphere superiority under multimodal presentation of emotional stimuli.

Adult↗
PubMed1996

Hemispheric asymmetry of arterial blood flow velocity changes during verbal and visuospatial tasks.

Changes in arterial blood flow velocity induced by cognitive activity were measured by simultaneous bilateral transcranial Doppler sonography (TCD) of the posterior and the middle cerebral artery. The finding of a robust left hemisphere dominance for verbal tasks but of an inconsistent right hemisphere dominance for visuospatial tasks obtained in an earlier study [13], in which TCD measurement had been restricted to the middle cerebral arteries, was confirmed. At the same time, it could be demonstrated that the failure to find the expected right hemisphere dominance for tasks of spatial visualization and mental rotation extended to the TCD measurement of the posterior cerebral arteries.

Adult↗
PubMed1995

Sensorimotor learning in ideomotor apraxia.

Sensorimotor learning ability in patients with ideomotor apraxia was investigated, using as subjects, eight patients with ideomotor apraxia, 8 with aphasia without ideomotor apraxia, and 8 normal controls. The aphasia, apraxia, and normal control groups were matched for age, sex, and education. The aphasia and apraxia groups were chosen to control for lesion size and scores on Kimura's recurring figure test, the Token test, and intelligence. The mirror-aiming test was performed and the learning effect in terms of decreases in total time, the number of errors, and the times for errors were examined. There was no statistically significant difference between the learning effect of the apraxic group and that of the aphasic group for total time, the number of errors, and the times for errors; however, there were group differences on each trial for number of errors and the times for errors. These results suggest that patients with ideomotor apraxia have some difficulties in motor performance rather than disturbance of learning.

Aphasia↗
PubMed1994

Transcranial Doppler ultrasonic assessment of middle cerebral artery blood flow velocity changes during verbal and visuospatial cognitive tasks.

Hemisphere specific changes of blood flow velocity in the right and left middle cerebral artery (MCA) induced by cognitive demands of verbal and nonverbal tasks were examined by means of a newly developed technique of simultaneous bilateral transcranial ultrasonic Doppler sonography (TCD). Thirty-one right-handed healthy volunteers served as subjects. Identical stimulus and response procedures were used with all tasks to avoid possible differential effects of these conditions on blood flow velocity. Compared to the preceding resting phase, the increase in flow velocity induced by each of the verbal tasks (sentence completion, similar or contrasting word meaning, similarities) proved to be significantly higher in the left than in the right MCA. Among the non-verbal visuospatial tasks only the "identical pictures" (perceptual speed) task led to a complementary higher increase in right MCA blood flow velocity. No such asymmetry in blood flow acceleration was observed, however, with the tasks "figure assembly" and "cube comparison" which require visualization and mental rotation of figures. The findings underline the recently emerging uncertainty in neuropsychological research with regard to the functional specialization of the right hemisphere.

Adult↗
PubMed1993

Decrease of contralateral neglect by neck muscle vibration and spatial orientation of trunk midline.

Three patients with a right hemisphere lesion and marked left-sided neglect without visual field defects were asked to detect and identify stimuli which were tachistoscopically presented in the left or right visual half-field. Neglect of stimuli presented in the contralesional left visual field, which was observed when the patient's body was in a normal upright position with trunk, head and gaze oriented straight ahead to the middle of the projection screen, could be reduced by vibrating the left posterior neck muscles as well as by turning the trunk 15 degrees to the left. In contrast, unspecific stimulation on the left side of the patient's body, produced by vibrating the left hand muscles or the proprioceptive signal induced by turning the head 15 degrees to the left, had no compensatory effects. The results showed that the afferent information about real lengthening of the left posterior neck muscles (produced by turning the trunk) as apparent lengthening of these muscles (produced by their vibration), leads to a remission of contralateral neglect. Thus, the proprioceptive input from the neck muscles, i.e. the head-on-trunk signal, appears to influence the extension of the neglected part of space in patients with neglect. The signal seems to contribute substantially to the neural generation of the egocentric frame of reference that allows the determination of body position with respect to visual space. We hypothesize that the reduction of neglect by vibration of the contralateral posterior neck muscles is based on a shift of the subjective spatial localization of the sagittal midplane in the contralesional direction and a corresponding alteration of the egocentric coordinate system necessary for visuomotor coordination and exploration of space.

Aged↗
PubMed1991

Short-term memory performance with magnetic stimulation of the motor cortex.

Whether transcranial magnetic stimulation of the motor cortex has an influence on memory was investigated. In a first experiment with 21 healthy volunteers six pronounceable nonsense words were visually presented, immediately followed by a magnetic stimulus. There were three blocks of stimulation with field intensities of 60, 80 and 100% (referring to a maximal intensity of 2 Tesla), each block comprising six magnetic stimuli and six nonsense words. After each block there was a free recall test and at the end another free recall trial as well as a multiple-choice recognition test for all 18 words. Eighteen subjects served as controls, undergoing the same procedure, except that the field intensity was zero. A significant but small reduction of short-term memory performance was observed only for 100% field intensity. In a second experiment with 16 subjects who had not participated in experiment I, the effect of 100% intensity cortical magnetic stimulation was compared with a control stimulation over the cervical spine. There was no difference in free recall or in the multiple-choice test between the sites of stimulation, suggesting that the difference in the 100% intensity block in experiment I was not due to a specific cortical effect of the magnetic field on memory function. With respect to the effect on memory functions, transcranial magnetic stimulation of the motor cortex is thought to be a safe method.

Adult↗
PubMed1988

Effects of spatial arrangement of letter pairs in a name-matching task with unilateral and bilateral hemifield stimulation.

In tachistoscopic studies requiring "same/different" judgements on pairs of stimuli, differences between unilateral and bilateral presentation have been interpreted in terms of higher level cognitive processing. However, unilateral presentation is usually confounded with vertical and bilateral presentation with horizontal arrangement of stimuli. The effect of various stimulus arrangements was examined in two experiments. The results gave no evidence for an independent effect of uni- vs bilateral presentation, but rather a strong effect of the spatial arrangement such that pairs arranged on a straight line through the fixation point yield faster reaction times than any other vertical or horizontal arrangement.

Adult↗
PubMed1988

Left hemispheric interference with nonverbal performance in aphasics: comparison with data from split-brain studies.

Two nonverbal tasks (Nebes' Figural Unification Test and Arc-Circle Matching Task) were given to 10 aphasic patients and 10 normal controls. Observations in split-brain patients have shown that the right hemisphere performs almost normally on these tasks while the left hemisphere fails completely. Left and right hand performances of aphasics and controls were compared with those of split-brain patients as reported in the literature. In the Figural Unification Test the aphasics' left hand performance was significantly poorer than that of split-brain patients. This is interpreted as an effect of left hemispheric interference with right hemispheric nonverbal performance. The lack of a similar impairment of left hand performance in the Arc-Circle Matching Task suggests that this interference is only provoked by tasks which, due to the possible verbalization of stimulus material, tend to stimulate left hemispheric activity.

Aged↗
PubMed1987

Residual information processing in the neglected visual half-field.

A patient with neglect of visual half-field without hemianopia performed "same/different" interfield comparisons and named stimuli presented either unilaterally or bilaterally in the visual half-fields. With unilateral presentation he could name all stimuli in both fields, whereas with simultaneous bilateral stimulation his performance decreased to about 50% correct naming of left visual field (LVF) stimuli. This performance was not improved by cueing for the presence of LVF stimuli. Interfield comparisons were 100% correct in all conditions. It is concluded that inattention for the left hemispace in patients with visual neglect occurs whenever information in the right hemi-space attracts attention or must be consciously processed. Simple "same/different" judgements are presumably performed on a pre-attentional level and are not affected by neglect.

Brain Diseases↗
PubMed1987

Influence of figural complexity on the identification of Kanji and Kana characters.

Kana, simple Kanji, and complex Kanji characters differing in figural complexity (number of strokes) were tachistoscopically presented to the right and left visual half-fields of 115 German subjects. The subjects had to decide whether a stimulus (lasting 150 ms) was the same as or different from a sample stimulus (lasting 1000 ms) presented immediately before to the center of the visual field. An increased left field advantage in reaction time with higher figural complexity was hypothesized (Visual Field X Type of Script interaction). Analyses of variance, however, did not show this interaction. Because of a significant Type of Script X Response Type interaction simple main effects were calculated which were all significant. Pairwise comparisons for type of script were significant except for Kana vs. simple Kanji. No other significant effects were obtained. Reaction times were shortest for simple Kanji, intermediate for Kana and longest for complex Kanji. The results indicate that high figural complexity of Japanese characters does not favour the left visual field.

Adult↗
PubMed1986

Effect of visual complexity in tachistoscopic recognition of Kanji and Kana symbols by German subjects.

Kana and Kanji characters differing in figural complexity, as defined by the number of strokes, were presented tachistoscopically in the right and left visual field to 20 right-handed German subjects not familiar with Japanese script. Neither an interaction between complexity of script and visual field nor any simple main effect of visual field were obtained. It is concluded that the complexity of the different types of script is not critical for visual field asymmetries observed in experiments dealing with the recognition of Kana and Kanji in Japanese subjects.

Adult↗
PubMed1985

Is there parallel and independent hemispheric processing of intonational and phonetic components of dichotic speech stimuli?

The possibility of hemisphere interaction in the processing of spoken language was studied in two dichotic listening experiments. The stimulus material consisted of six CV syllable triplets each spoken with each one of six intonation contours. In Experiment I, 15 aphasic patients, 8 patients with unilateral right hemisphere lesions, and 10 normal controls were asked to identify the four components of a dichotic item from a multiple-choice (MC) set comprising all possible CV triplets and intonation contours. In Experiment II, 30 normal subjects were required to identify either the right or left ear stimulus alone from an MC set comprising the right and left ear stimulus together with the two wrong combinations of right ear CV triplet with left ear intonation and vice versa. It is concluded from the results that the left hemisphere is capable of processing both phonetic and intonational information and that there is neither the necessity nor the tendency for right hemisphere participation in the perception of spoken language.

Adult↗
PubMed1985

Influence of contextual complexity on the processing of cartoons by patients with unilateral lesions.

It was examined whether the performance of right hemisphere patients in the comprehension of cartoons is predominantly influenced by disturbed processing of affective material or by cognitive deficits. Cartoons differing in their cognitive demand were presented to groups of right hemisphere patients, aphasics and normal controls. Subjects were required to identify the cartoon in a multiple choice set of four pictures. Additionally, subjects were asked to rate the funniness on a three-point scale. The results indicate that the impairment of right hemisphere patients is caused by a combination of visuo-perceptive and cognitive deficits rather than by an inability to identify the affective component of cartoons.

Adult↗
PubMed1984

Electromyographic feedback treatment of chronic hemiparesis: an attempt to quantify treatment effects.

The efficacy of electromyographic (EMG) feedback for the treatment of chronic upper extremity hemiparesis was quantitatively assessed through a series of objective and standardized tests of motor skills given to 12 stroke patients before and after treatment. In addition to standardized tests, video recordings of patient performance during simple motor tasks were made before and after EMG feedback training to permit subjective ratings of patient performance. Only six patients were able to perform the standardized tests of motor skills in a way permitting meaningful evaluation of results, and their test scores showed no significant improvement after treatment. Ratings of the video records by 37 independent physical therapists showed that some improvement of gross motor performance could be observed at the level of subjective global evaluation.

Adult↗