Biomedical subjects

D Timmann

Publications and source records attributed to D Timmann.

59 records · Page 4Linked to original sources

PubMed1994

Influence of visual and somatosensory input on leg EMG responses in dynamic posturography in normals.

The contribution of visual and somatosensory input to stabilization after sudden postural disturbances was investigated. Fast transient platform movements (50 degrees/sec, 4 degrees), rotating toe-up around the ankle-joint, evoke EMG responses in the triceps surae (TS) and anterior tibial (TA) muscles. The short and medium latency responses (SL, ML) in the TS destabilize, the long latency responses (LL) in the TA stabilize the upright posture. The influence of vision was tested in normals comparing the conditions eyes open with eyes closed. The influence of additional somatosensory input was tested with the operator's index finger touching the back of the subject with eyes closed. Absent visual input (eyes closed) resulted in a decrease in latency of the stabilizing LL response and an increase in the integrated EMG (iEMG). With eyes closed the latency of the LL response decreased by 4 msec on average (mean eyes open: 111.6 msec (S.D. = 17.3), eyes closed: 107.6 msec (S.D. = 17.5); P < 0.001 (Wilcoxon test)), the iEMG increased by 10% (mean eyes open: 13.9 microV.sec (S.D. = 7.6), eyes closed: 15.5 microV.sec (S.D. = 8.6); P < 0.001). Additional somatosensory input as an external reference for body orientation in space resulted in an increase in latency and decrease in iEMG: the latency increased by 7 msec on average (mean eyes closed: 107.6 msec (S.D. = 17.5), index finger and eyes closed: 114.7 msec (S.D. = 19.9); P < 0.001), the iEMG decreased by 20% (mean eyes closed 15.5 microV.sec (S.D. = 8.6), index finger and eyes closed: 12.3 microV.sec (S.D. = 7.5); P < 0.001). There was no significant change in latency of SL and ML. We conclude that postural EMG responses in leg muscles after fast transient platform movements change according to different functional demands, modulated via visual and somatosensory input.

Adolescent↗

PubMed1993

The role of vertebral and internal carotid artery disease in the pathogenesis of vertebrobasilar transient ischemic attacks.

Color-coded duplex sonography has improved the evaluation of the hemodynamics of the vertebral arteries (VA). A reliable differentiation between a normal vessel, hypoplasia, stenosis and occlusion of VA can now be made. We studied two groups of patients in a prospective study with isolated carotid artery disease (n = 48), and with a combination of carotid and vertebral artery disease (n = 14), to determine the role of VA in the pathogenesis of transient ischemic attacks (TIAs) in the vertebrobasilar system. Apart from the existing arteriosclerotic changes of the internal carotid arteries, the condition of the VA was of importance for the occurrence of TIAs in the vertebrobasilar territory. We found that 8% of the patients with isolated hemodynamically relevant stenosis or occlusion of one or both internal carotid arteries had a TIA in the vertebrobasilar territory. Patients with combined carotid and vertebral artery disease had an increase of TIAs in the same region in 71%. The high rate of TIAs in this group might be attributed to the combined effect of carotid and vertebral artery disease, as a third group (n = 30) with isolated vertebral artery disease showed TIAs in only 13%.

Blood Flow Velocity↗

PubMed1992

[Doppler and duplex sonography of the vertebral arteries].

In a prospective study 451 patients were examined with extracranial CW-Doppler sonography (mastoidal slope), suboccipital transcranial Doppler sonography and colour-coded duplex sonography to evaluate unusual vertebral arteries (hypoplasia, stenosis and occlusion). Colour duplex sonography was used as reference method. CW-Doppler sonography had a sensitivity of 100% and a specificity of 27% for the detection of an unusual vertebral artery. For transcranial Doppler sonography these values are 38% and 58%. Our study showed that CW-Doppler is a useful screening examination for identifying pathological findings of vertebral arteries. In case of abnormalities in CW-Doppler, duplex sonography, especially colour-coded duplex sonography, should be added.

Adult↗

PubMed1990

Diagnostic significance of tibial nerve somatosensory evoked potentials (spinal and cortical components) with spinal cord lesions.

Forty normal subjects were investigated with the somatosensory evoked potential technique following stimulation of the posterior tibial nerve in order to yield information upon normal values, and especially the origin of the cervical potential. Subsequently an electrophysiologic localization of tumours along the spinal cord was attempted in 18 patients with spinal tumours. In C2 recordings with Fz reference 3 components, N28, N30, and N34, are visible. Simultaneous cortical and cervical recordings with mastoid, knee, and neck references suggest a cranio-cervical origin of N28, a subcortical origin of N30 and a thalamic or thalamo-cortical origin of N34. In patients, the lumbar spinal cord potentials regularly yielded a useful additional information with respect to the tumour site. The cervical potentials added in 5 out of 18 patients additional information localizing the tumour within the spinal cord or brain-stem.

Adult↗

PubMedDate not supplied

Liposarcoma with unusual neurological manifestations.

Central nervous system involvement in liposarcoma is rare, the only symptom reported in the literature being local compression of the spinal cord. An exceptional case with peripheral nerve involvement due to local recurrence, in addition to spinal cord compression and cavernous sinus syndrome due to metastases is reported.

Adult↗