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Biomedical subjects

E Altenmüller

Publications and source records attributed to E Altenmüller.

At least 37 records · Page 2Linked to original sources
PubMed1998

Brain potentials in patients with music perception deficits: evidence for an early locus.

Twelve patients with an acute cerebrovascular accident were assigned to a group with music perception deficits (amusia, n = 6) or a group without such deficits (n = 6) on the basis of a new test-battery for music-perception skills. Event-related brain potentials (ERPs) were recorded in an auditory classification task designed to elicit several components; the N1 as a correlate of initial auditory cortical processing, the P3a as an index of automatic attentional orienting, and the P3b as a measure for controlled stimulus evaluation. Patients with amusia showed a significant amplitude decrement for the P3a relative to controls and patients without amusia suggesting an impairment of early stimulus evaluation. P3b was reduced in both patient groups relative to control. These data show that amusia is quite common in unselected stroke patients and suggest deficits of generic rather than music-specific cognitive processes as the underlying cause.

Acoustic Stimulation↗
PubMed1998

Assessment of dynamic finger forces in pianists: effects of training and expertise.

Playing a musical instrument requires complex sensorimotor programming of hand and finger movements. During musical training motor programs are optimized to achieve highest accuracy with a minimum of effort. In the lack of handy measurement tools these rational assumptions of piano theorists did not undergo an experimental evaluation up to now. In the present pilot study we used a dynamic pressure measurement system with the pianoforte. Three finger exercises with increasing degrees of difficulty had to be performed by a group of musical amateurs and a group of expert players. From the dynamic force measurements we calculated (a) the mean pulse per touch and (b) the mean touch-duration for each exercise and each subject. To achieve the same tempo and the same loudness, amateurs applied significantly more and longer force to the keys, leading to higher mean pulses per touch. Pulse and duration values increased with higher demands on finger coordination in both, expert pianists and amateurs. The results show that dynamic force measurement systems can support music learners and teachers in training a relaxed piano technique and preventing musicians from overuse injuries.

Adolescent↗
PubMed1997

The cortical processing of perceived emotion: a DC-potential study on affective speech prosody.

Direct current (DC) components of the EEG signal were recorded in 16 right-handed subjects during presentation of pairs of declarative sentences with either happy, sad or neutral intonation. Each stimulus pair had identical wording, but differed at the acoustic level either in pitch (fundamental frequency = FO) range or in duration of stressed syllables. Subjects were asked, first, to identify the emotional category of each sentence pair and, second, to indicate the utterance displaying stronger emotional expressiveness. Stimuli with happy or sad intonation, as well as FO-manipulated neutral sentences, yielded a significantly lateralized negativity towards the right hemisphere (RH). Compared with FO-varied neutral utterances, the discrimination of time-manipulated neutral stimuli resulted in significantly reduced amplitudes, predominantly over RH areas. These results corroborate the suggestion of a dominant role of the RH for the evaluation of the emotional significance of sensory input.

Acoustic Stimulation↗
PubMed1997

Language processing in aphasia: changes in lateralization patterns during recovery reflect cerebral plasticity in adults.

During single word processing the negative cortical DC-potential reveals a left frontal preponderance in normal right-handers as well as in patients with a history of transient aphasia. Lateralization of DC-negativity therefore provides a reliable and robust method for the assessment of language dominance. In 11 stroke patients with permanent aphasia this physiological pattern changed to bilateral activation reflecting an additional right-hemispheric involvement in compensatory mechanisms in aphasia. Along with complete clinical recovery the classical aphasic syndromes revealed specific differences in changes of their lateralization patterns. In Broca's aphasia the initial right-hemispheric preponderance changed to a left frontal lateralization while in Wernicke's aphasia a presumably permanent shift towards the right hemisphere occurred. Differences in lateralization patterns might reflect different mechanisms of recovery such as the initial disinhibition of homologous areas contralaterally and subsequent collateral sprouting and synaptic modulation. The assessment of changes in lateralization of the cortical DC-potential during language tasks in a non-invasive, safe method with excellent time resolution that might provide further insights in the neural basis of recovery from aphasia.

Action Potentials↗
PubMed1996

The use of flash visual evoked potentials in the early diagnosis of suspected optic nerve lesions due to craniofacial trauma.

Craniofacial trauma encroaching on the orbital apex and optic canal can result in direct or indirect optic nerve lesions, leading to visual impairment or blindness. Early diagnosis of a visual loss and immediate therapy are generally considered crucial for a successful restoration of vision in indirect trauma. However, in comatose or sedated patients the assessment of optic nerve function by testing pupillary reactivity may be severely compromised or impossible because of tensely swollen eyelids, conjunctival oedema, concussion of the ciliary muscle or pharmacological effects. In the event that clinical ophthalmic examination, computer tomography or nuclear magnetic resonance scanning fail to clarify the state of the optic nerve, visual evoked potentials (VEPs) to flash stimulation appear to provide reliable information on function within the visual pathway. On this basis, treatment with corticosteroids and/or surgical decompression can be rapidly initiated. Our results in a preliminary patient series confirm the value of acutely monitored VEPs as an objective test of optic nerve function in cases of suspected optic nerve injury immediately after admission to the emergency care unit. The imaging techniques usually applied may be complemented by VEPs to show the functional significance of structural abnormalities found in the vicinity of the optic nerve.

Adult↗
PubMed1995

Gating of sensation and evoked potentials following foot stimulation during human gait.

To investigate how gait influences the perceived intensity of cutaneous input from the skin of the foot, the tibial or sural nerves were stimulated at the ankle during walking or running on a treadmill. As compared to standing, the detection threshold for these stimuli was raised by more than 30% during the locomotion tasks. During walking, there was a phase-dependent modulation in perceived intensity of suprathreshold stimuli (1.5, 2, or 2.5 x PT). Stimuli given just prior to footfall were perceived as significantly above average (Wilcoxon signed-rank test). In contrast there was a significant phasic decrease in sensitivity for shocks delivered immediately after ipsi- and contralateral footfall. The amplitude of somatosensory evoked potentials (P50-N80 complex), simultaneously evoked from pulse trains to the sural nerve and recorded at scalp level, was, on average, 62% of the level during standing. During gait, the amplitude of this complex was significantly smaller just after footfall than the amplitude during late swing (MANOVA). It is suggested that the reduced sensation and the decreased evoked potentials after touchdown may be due to occlusion or masking by concomitant afferent input from the feet. On the other hand, the phasic increase in sensitivity at the end of swing is thought to result from a centrally generated facilitation of sensory transmission of signals in anticipation of foot-placing.

Adult↗
PubMed1995

Modulation of sural nerve somatosensory evoked potentials during stance and different phases of the step-cycle.

In order to investigate the modulation of somatosensory processing during stance and locomotion, sural nerve somatosensory evoked potentials were recorded during both stance and different phases of the step-cycle. Characteristic sequences of negative-positive waves were elicited, consisting of an early component, N40, presumably of subcortical origin, followed by a P50-N80-P220 complex of cortical origin. The N40 and N40-P50 components had similar amplitudes in both gait and stance. However, the P50-N80 component was attenuated whereas the N80-P220 complex became biphasic during gait. Within the step-cycle, amplitudes of the cortical components P50-N80 and N80-P110 were larger prior to footfall and smaller at the beginning of the support phase. The results demonstrate that locomotion produces a modulatory effect on somatosensory input at a cortical level. Within the step-cycle, excitability of the somatosensory cortex is increased during the middle and late swing phases and decreased during the support phase. Such modulation may contribute to an improved detection of foot contact at touchdown.

Adult↗
PubMed1993

Cortical DC-potentials in identification of the language-dominant hemisphere: linguistical and clinical aspects.

In order to find a non-invasive method for determining the hemispheric dominance for language, we studied cortical activation patterns during language processing by means of electrophysiological techniques: DC-potentials were recorded from frontal, central, temporal and parietal electrode positions in 28 right-handed normal subjects and in 16 patients with a history of transient loss of speech and known hemispheric dominance. Subjects were asked to find as many synonyms as possible within 6 seconds to either a concrete or an abstract noun. This task caused a highly significant left-hemispheric lateralization over frontal and central, but not over temporal and parietal cortical areas. Search for synonyms to abstract nouns yielded frontal left-hemispheric dominance in 93% of all normal subjects, search for synonyms to concrete nouns in 85%. Inter-electrode correlation coefficients were higher during processing of abstract word categories than during processing of concrete categories. In all patients, frontal and central lateralization corresponded to their hemispheric dominance as determined from clinical data. Advantages as well as inconveniences of this technique are discussed and compared to other invasive and noninvasive tools of assessing speech lateralization.

Adolescent↗
PubMed1992

[Nerve injuries following nerve blocking in the pterygomandibular space].

In a prospective study 506 patients with nerve blocks in the pterygomandibular space were examined before and 3-7 days after local anaesthesia. Clinical neurosensory testing including two-point discrimination revealed no differences between the neurological status before and after injection. Between December 1987 and April 1991 8 patients with 9 nerve injuries (lingual nerve n = 8, inferior alveolar nerve n = 1) after nerve blocks in the pterygomandibular space were treated. In addition to hypaesthesia or anaesthesia 5 out of 8 patients with injection damages of the lingual nerve suffered from a loss of taste sensations. Only 2 of the total of 9 nerve lesions showed a complete recovery of the neurological deficit. One patient with a persistent pain syndrome of the lingual nerve after an injection damage underwent partial nerve resection and microsurgical reconstruction after intraoperative monitoring of somatosensitive-evoced-potentials. The operation was successful for only a few weeks, afterwards a relapse of the pain syndrome took place.

Anesthesia, Dental↗
PubMed1991

Effects of the anticonvulsant benzodiazepine clonazepam on event-related brain potentials in humans.

The effects of the benzodiazepine clonazepam (a drug used as anticonvulsant) on event-related brain potentials were investigated in healthy human subjects. Thirty-six male student volunteers (mean age 30 years) received clonazepam or a placebo in a double-blind setting. VEPs (visual evoked potentials) were obtained from the standard checkerboard reversal procedure; AEPs (auditory evoked potentials) and slow cortical potentials (CNV) were measured during a 2-stimulus reaction time paradigm, in which the quality of the acoustic S1 signalled whether the acoustic S2 would follow after 2 sec or after 6 sec. Each S2 requested a speeded button press. Compared to placebo, clonazepam significantly reduced P100 amplitude of the VEP and the amplitudes of the AEP components N1 and P3. On the other hand, clonazepam boosted the development of a distinct N2 which was not apparent in placebo subjects. The CNV was significantly reduced and reaction time increased under clonazepam compared to placebo. Specific versus non-specific damping effects of the benzodiazepine are discussed, comparing the present result with the pattern of ERP effects of the anticonvulsant carbamazepine that had been obtained using the same experimental paradigms.

Adult↗
PubMed1991

[Flash-evoked visual potentials in the early diagnosis of optic nerve injury due to craniofacial fractures].

Impairment or loss of vision due to optic nerve injury occurs in about 10% of patients with cranio-facial fractures. The assessment of optic nerve function is important for decisions regarding optic nerve decompression. But examination of vision and pupillary reflexes may be difficult, especially in uncooperative patients with reduced consciousness and primary disturbances of pupillary functions. In these cases, optic nerve function can be monitored by means of flash-evoked visual potentials elicited by use of a LED-goggle stimulator. VEPs were recorded in ten patients with head injuries comprising cranio-facial fractures and cerebral concussion with prolonged alteration of consciousness. Recordings were obtained in the acute phase upon admission. Visual acuity and visual fields were examined after regaining consciousness and the clinical findings correlated to the initial VEPs. Upon clinical examinations, four patients with initially normal VEPs had normal vision on both eyes. One patient initially revealed unilateral reduction of the VEP-amplitude of more than 50% and clinically showed a concentric visual field defect. Three patients with unilateral loss of potentials were amaurotic on this side. Perception of light was preserved in one patient in whom VEPs were absent. One patient with bilateral loss of potentials was blind when consciousness was regained. In general, pupillary light reflexes tested at admission corresponded to the VEP-findings. In two cases, however, pupillary reactivity was lost, but VEPs were still present. These patients had normal vision, but exhibited a lesion of the efferent pathways of pupillary reflexes. In two other patients, examination of pupillary reactivity could not be performed due to extreme edema of the eyelids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Aberrant regeneration in a case of syringobulbia: selective co-activation of abducens and facial nerves during saccades.

A patient suffering from syringobulbia and syringomyelia exhibited a phasic contraction of the ipsilateral facial muscles, mainly the levator labii, whenever he looked to the left or right. Facial muscle twitches occurred exclusively with saccades. The selective co-activation of abducens and facial nerves is interpreted as the result of bilateral misrouting of regenerating neurons from the parapontine reticular formation to the facial nerve in the tegmentum pontis.

Abducens Nerve↗
PubMed1989

Premotor programming and cortical processing in the cerebral cortex. Electrophysiological correlates of hemispheric dominance.

Slow brain potentials were averaged from 12-15 EEG records (t = DC or 5 s) before and during voluntary hand movements and writing, spatial vision, language, and calculation tasks without vocalization and with visual fixation. EOG and writing pressure or EMG were recorded simultaneously. Skilled actions caused largest negative potentials in the contralateral sensorimotor hand area. Left-sided lateralization or bilaterally equal surface-negative potential shifts appeared during language and calculation tasks in 90% of the right-handers and in 75% of the left-handers. Right-sided lateralizations occurred during the viewing of perspective Necker figures or random-dot stereograms in the large majority of all subjects.

Adolescent↗
PubMed1989

Cortical DC-potentials as electrophysiological correlates of hemispheric dominance of higher cognitive functions.

Cortical activation during cognitive processing was assessed with a new, noninvasive electrophysiological method: Cortical DC-potentials were recorded from frontal, central, temporal and parietal electrode positions on the scalps of 150 normal adult subjects while they performed cognitive tasks involving language, calculation, music and spatial vision. During the 10-s registration period, shifts in DC-potentials were analyzed with reference to a baseline 3-s preperiod. 15-30 trials were averaged. A lateralized preponderance of negativity by more than 3 microV was used as the criterion of hemispheric dominance. Language tasks caused left-sided lateralization in 76% of the right-handers (n = 80), bilaterally equal surface negativity in 15% and right-sided lateralization in 9%. During the same tasks, 22% of the left-handers (n = 45) had right-sided lateralization. Calculation tasks produced left-sided lateralization in 65% of the right-handers and left-handers. Music tasks caused more right-sided (53%) than left-sided (39%) lateralization dependent on musical training. Visuospatial processing yielded a right temporoparietal lateralization in 77%.

Adolescent↗
PubMed1986

[Brain electrical correlates of cerebral music processing in the human].

Slow brain potentials were recorded during musical tasks in 60 healthy subjects (42 right-handers and 18 left-handers). In period I the tasks (pitch comparison or distinguishing of chords) were solved and in period II the results were written down. Eye movements and vocalizations were avoided. Unilateral lateralizations of negative potentials, recorded in transversal leads between corresponding brain regions, were determined from a baseline measured in a 3s pretest period. Left-sided or right-sided lateralizations in frontal, precentral, parietal and temporal regions were taken as evidence for a stronger activation of the underlying cortical areas. During period I, music tasks caused a right-sided lateralization in 53%, a left-sided one in 39% and no lateralization in 8% of the subjects. Language and calculation tasks, however, showed greater than 80% left-sided lateralizations in the same subjects. In period II lateralizations appeared contralateral to the writing hand, mainly in pre-central leads. The subjects (N = 60) were divided into 3 groups on the basis of their musical training: 20 non-musicians, 20 amateurs and 20 professional musicians were compared. A right-sided lateralization occurred more often in non-musicians and amateurs than in professionals. Right-handers and left-handers had about equal right-sided lateralizations in musical tests. But in left-handers bilateral negativity without lateralization occurred more often and left-sided lateralization less often than in right-handers. In 20 right-handers the passive experience or enjoyment of music was investigated. While only listening to music without tasks performance 8 subjects had a right-sided lateralization, 6 a left-sided one and 6 had bilateral negativity without lateralization. We conclude that music processing, unlike language processing, is not dominant in one hemisphere. It is suggested that electrophysiological correlates of hemispheric lateralization during musical tests may depend on musical training and handedness, but statistical significance needs further investigations on more subjects.

Adult↗
PubMed1984

[Hemispheric dominance for speech and calculation: electrophysiologic correlates of left dominance in left handedness].

Slow brain potentials were recorded in left-handers and right-handers during: (i) processing of language and mental arithmetic tasks, without vocalization, and (ii) subsequent writing down of the answers with either the right or left hand. Left-sided laterality of negative potentials was taken as evidence of hemispheric dominance. It appeared during the processing of words and numbers in 26 of the 30 left-handers and was localized mainly in the left frontal and temporal parietal regions. Similar results were found with the right-handers. This electrophysiological evidence indicates that the left hemisphere is dominant for language and calculation in the vast majority of left-handers. Only when writing with either their left or right hand do left-handers show less left-sided laterality than right-handers.

Adolescent↗