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Biomedical subjects

D von Cramon

Publications and source records attributed to D von Cramon.

At least 37 records · Page 2Linked to original sources
PubMed1984

Brain-stem auditory-evoked potentials in post-comatose patients after severe closed head trauma.

Brain-stem auditory-evoked potentials (BAEPs) were recorded in 35 post-comatose patients after severe closed head trauma. Compared to the normal BAEPs obtained from 30 normal controls, significant individual abnormality could be detected in only 2 patients. This abnormality consisted of lateral asymmetry, but not prolonged interpeak latencies or abnormal amplitude ratios. Further, no differences were found between groups as regards interpeak latencies. A significant reduction of BAEP amplitudes was seen in the patient group, being most pronounced in the 13 patients with hearing loss. It is concluded that the BAEP does not sufficiently reveal brain-stem lesions expected to persist after severe closed head trauma, presumably because the structures generating waves IV and V are not permanently affected. The amplitude reductions observed may be explained by the diffuse cochlear damage known to occur concurrently with head trauma.

Adolescent↗
PubMed1984

Acoustic measurement of voice quality in central dysphonia.

Speech samples of 14 male and 10 female patients with central dysphonia were examined. Eighteen patients had suffered a severe closed head trauma and the remaining six patients had experienced cerebrovascular accident (CVA). Several parameters were developed in order to find acoustic correlates for three major pathologic voice qualities in central dysphonia. The well know jitter parameter, fundamental period perturbation (PP), was adapted for our purposes and proved to be a good measure for rough voices, though the patients revealed less jitter than in peripheral dysphonia. The vocal onset parameter, time lag of preexhalation (Tb), and the spectral parameter, spectral energy above 5 KHz (A5), classified the breathy voices. Most of the tense voices could be detected by the spectral parameters, spectral energy in the 1-5 KHz range (A1), and variance of spectral energy above 5 KHz (V5). The successful classification of these voice qualities allowed the description of compound pathologic voice types in central dysphonia.

Adolescent↗
PubMed1984

[Laryngoscopic findings in dysphonia following traumatic midbrain syndrome].

26 patients with traumatic voice disorders were examined laryngoscopically. During the initial mute stage, reflex vocal cord movement could be detected but no intentional movement. A gradual approximation of the vocal cords led to a narrowing of the glottic aperture so that whispering but not voiced phonation, was possible (stage of whispering). The third stage was characterized by the rapid development of a laryngeal (and pharyngeal) spasticity, identifiable by shortened and thickened vocal folds, an increased approximation of the ventricular folds and in a more dorsal position of the epiglottis. During phonation hyperadduction of the anterior two thirds of the vocal cords occurred with an accompanying open posterior chink (stage of spastic dysphonia). In some patients an incomplete, unilateral vocal cord abduction during respiration was observed which is most probably the result of an unilateral (contralateral) laryngeal hemispasticity. In other patients spontaneous (uni- and bilateral) laryngeal hyperkinesias were also present.

Brain Injuries↗
PubMed1983

The anterior cingulate cortex and the phonatory control in monkey and man.

Electrical stimulation of the anterior cingulate cortex yields vocalization in the monkey. The elicited vocalizations seem to represent primary stimulus responses. Monkeys are not able to perform a vocal conditioning task after ablation of the anterior cingulate cortex. However, they can carry out a lever-pressing conditioning task following destruction of this area. It is hypothesized that the anterior cingulate cortex exerts the volitional control of species-specific vocalizations in monkey. The non-verbal emotional vocal utterances are considered to be the human homologue of monkey's vocalizations. Therefore, bilateral lesion of the anterior cingulate cortex in man should hamper the volitional control of emotional vocal utterances in man as it does in monkeys. One personal observation is reported where after a bilateral infarction of the anterior cingulate cortex the patient's voice showed a permanent lack of emotional expression. The anterior cingulate cortex seems to play the decisive role in the volitional verbalization of emotions.

Animals↗
PubMed1983

Selective disturbance of movement vision after bilateral brain damage.

A patient who suffered bilateral posterior brain damage exhibited disturbance of movement vision in a rather pure form. The patient had no impression of movement in depth, and could only discriminate between a stationary and a moving target in the periphery of her otherwise intact visual fields. She had some movement vision in the central part of her visual fields, provided that target velocity did not exceed 10 deg/s. Neither did she possess visual movement after effects nor apparent (phi) visual movement. In addition, visually guided eye and finger movements were impaired. In contrast to the disturbance of movement perception in the visual modality, movement perception elicited by acoustic and tactile stimuli was not impaired. On the basis of the localization of the cerebral damage (as judged by CT scanning and neuropsychological testing) it is concluded that the observed disorder in movement vision is due to bilateral cerebral lesions affecting the lateral temporo-occipital cortex and the underlying white matter. The selectivity of the visual disturbance supports the idea that movement vision is a separate visual function depending on neuronal mechanisms beyond the primary visual cortex.

Adult↗
PubMed1983

Vowel distortion in traumatic dysarthria: a formant study.

The frequencies of the first two formants of three German vowels in word context were determined by a formant tracking routine for 8 male subjects with closed head trauma. A centralized formant pattern was found to characterize vowel articulation in traumatic dysarthria. Different degrees of severity could be assessed and the process of recovery was described by the parameter 'formant triangle area'. An interpretation in articulatory terms is given and the results are discussed in the light of articulatory models.

Adult↗
PubMed1983

Vowel distortion in traumatic dysarthria: lip rounding versus tongue advancement.

Formant analysis of tense, high, German vowels was performed to the end of obtaining information about the role of insufficient lip rounding in distorted vowel production of 8 traumatic dysarthrics. A comparison was made between two allophones of /y/ in different consonantal contexts. Noticeable undershoot in lip rounding or protrusion proved to occur in a context of conflicting labial gestures. Where the articulatory realization of a CVC sequence required gross tongue movements, a lingual undershoot resulted as the prevailing deficit. No evidence for dyscoordinative defects was obtained from the results.

Brain Injuries↗
PubMed1982

Electrodermal response patterns in neurological patients with disturbed vigilance.

In 18 neurological patients with severely disturbed vigilance and 18 healthy subjects, electrodermal responses to acoustic stimuli were elicited. There were substantial differences between both groups in the temporal patterning of electrodermal responses. Patients reacted significantly less on initial trials than healthy subjects and exhibited their maximal responses on later trials. This response pattern is interpreted as reflecting changes in activation.

Acoustic Stimulation↗
PubMed1982

The effects of deep-reaching lesions in the cortical face area on phonation. A combined case report and experimental monkey study.

The present study compares the phonatory ability of a patient with a deep-reaching left-sided lesion in the region of the cortical face area with that of two squirrel monkeys in which the patient's lesion has been reduplicated bilaterally. The lesion involved Broca's area, the inferior pre- and postcentral cortex, rolandic operculum, inferior parietal cortex insula, claustrum, parts of the putamen and white matter underlying the inferior frontoparietal and insular cortex. While the squirrel monkey did not show any phonatory deficits, the patient became aphonic for more than 10 weeks following the insult. After that period, phonation recovered steadily to a slightly breathy but monotonous voice with a somewhat reduced singing capacity. During the aphonic period, there was a bilateral complete paresis of the vocal folds. Both, patient and monkey, showed a paresis of the lower facial and tongue muscles which was accompanied by dysarthria and buccolingual apraxia in the patient and feeding difficulties in the monkey. The discrepancy between human aphonia and intact monkey phonation, on the one hand, and intact phonation and defective orofacial behaviour in the monkey, on the other, is explained by the anatomical fact that there is a direct cortical projection to the nucleus ambiguus in man but not in monkey, whereas the facial and hypoglossal nuclei receive direct cortical projections in man and monkey. The lack of direct cortical control of the laryngeal motoneurones in the monkey is paralleled by a lack of volitional control of fine vocal fold movements.

Animals↗
PubMed1982

[Disorders of voluntary eyelid movements (author's transl)].

Isolated disturbances of voluntary lid movements are a symptom which has been rarely described, and to which widely differing labels have been applied. Three different symptoms can be described from the cases reported in the literature: disorder of voluntary lid closing and/or opening, cortical ptosis, and inability to keep the eyes closed for more than a few seconds ("motor impersistance"). This last symptom can be considered as an unspecific sign of brain-damage. For the disturbance of voluntary lid opening/closure, the term "cortical palsy" of lid movements is proposed. Thus this symptom can be differentiated from other supranuclear disorders of lid movements where reflectory and/or spontaneous lid movements are also impaired. As in all cases reported, the elementary motility of the eyelids (opening and closure) is impaired, it is not possible to ascertain whether a lid-apraxia is present.

Blepharoptosis↗
PubMed1982

Restitution of visual field in patients with damage to the geniculostriate visual pathway.

Previous experiments have investigated the effect of specific practice on partially blinded monkeys after striate cortex lesions. Similar procedures were adapted for patients suffering homonymous field defects due to geniculostriate damage. Both methods, light detection and saccadic localization, led to an enlargement of the visual field. The amount of this enlargement depended on the eccentricity of the field border as well as on the level of light sensitivity in the region between the intact field and the scotoma. Recovery of visual field included the reappearance of various visual functions (e.g. visual acuity, color identification). In periods without training visual field did not recover. It is hypothesized that recovery can take place at the level of the striate cortex, and is mediated by structures interacting with the striate cortex, e.g. the superior colliculus.

Adult↗
PubMed1981

The acoustic blink reflex: stimulus dependence, excitability and localizing value.

The acoustic blink reflex was examined in 26 subjects with open eyes and 20 subjects with closed eyes by means of an electrooculogram. Amplitude and excitability are highly dependent on the loudness of the stimulus used and on the opening or closure of the eyelids. Particularly if the eyes are closed, it may be necessary to use a stimulus of high (105-110 dB SPL) intensity (hand-clapping is often not loud enough). If an acoustic blink reflex can be elicited, it can be assumed that certain pontine and mesencephalic structures are intact.

Acoustic Stimulation↗