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Biomedical subjects

T Brandt

Publications and source records attributed to T Brandt.

At least 19 recordsLinked to original sources
PubMed2006

Low recurrence rate of vestibular neuritis: a long-term follow-up.

We examined 103 patients with vestibular neuritis (VN) in a follow-up study (5.7 to 20.5 years, mean 9.8 years). Two patients (1.9%) had developed a second occurrence of VN 29 to 39 months after the first. VN affected the contralateral ear in both and caused less severe distressing vertigo and postural imbalance. Unlike Bell's palsy and sudden hearing loss, a relapse in the same ear did not occur.

Adult↗
PubMed2006

How to see what you are looking for in fMRI and PET--or the crucial baseline condition.

The identification of a baseline or control state is fundamental for the interpretation of task- or stimulation-induced brain activation patterns. The conscious resting state in darkness is a frequently used, but ill-defined mental state. The mere transition from, for example, lid closed to lid open in darkness causes major changes in brain activity,which can mask or mimic a stimulus-dependent brain activation. Contradictory results of seemingly identical brain activation studies may be attributed to the choice of different baseline conditions. Therefore, control conditions that are closest to the stimulus or task condition should be used as baseline in most fMRI and PET studies rather than absolute relaxation in darkness and silence (REST).

Brain Mapping↗
PubMed2006

Detection of floccular hypometabolism in downbeat nystagmus by fMRI.

The authors evaluated floccular activity with fMRI during the performance of vertical smooth pursuit eye movements in four patients with downbeat nystagmus (DBN) due to cerebellar degeneration and in 16 healthy controls. Region of interest analysis revealed a significantly diminished activation of both floccular lobes during downward but not upward pursuit in DBN. These imaging data support the view that a functional deficiency of the flocculi in downward pursuit causes DBN.

Aged↗
PubMed2006

[Polysomnographic as a therapeutic aid in of psychogenic-functioning paraplegia].

The case of a patient with complete sensory and motor paraplegia for more than 1 year is presented. Leg movements were documented during sleep by video and electromyographic recording because a psychogenic cause of the symptoms was suspected. We showed the video to the patient, which illustrated that leg movements were possible. This resulted in fast and complete resolution of the neurologic symptoms. The patient has now been free of them for more than 3 years. This example suggests that the achievement of consciousness of normal motor function is a therapeutic approach for long-standing improvement of psychogenic paralysis.

Adult↗
PubMed2006

[Clinical treatment and therapy for dissected cervicocerebral artery].

Dissection of a cervicocerebral artery (CAD) is the second leading cause of stroke at younger ages. The pathogenesis of spontaneous CAD is not fully clarified. Defective connective tissue components may cause an arteriopathy predisposing to CAD in combination with certain trigger and risk factors. The clinical spectrum includes local pain in the neck, headaches, Horner's syndrome, isolated cranial nerve deficits, and hemispheric or brainstem infarction. Noninvasively, CAD is confirmed by Duplex sonography, MRI, and MRA. There is no controlled study for best treatment or management. Rational initial empiric treatment in acute CAD to prevent secondary embolism is partial thromboplastin time-guided anticoagulation by intravenous heparin followed by anticoagulation with warfarin. Carotid surgery for treating CAD is not recommended. The duration of anticoagulation is best guided by Doppler sonography follow-up and should extend until normalization of blood flow or at least 6 months after the vessel was occluded. Caution should be recommended for exercises that involve excessive head movements. The recurrence rate for CAD is low at <1%/year except for patients with known hereditary connective tissue disorders or in cases with familial dissections.

Aortic Dissection↗
PubMed2005

How the eyes move the body.

The increased postural sway of patients with disorders of the vestibular system improves with vision. The suppression of pathologic nystagmus also reduces sway. Because the latter effect cannot be attributed to retinal slip as a relevant feedback for postural control, the authors investigated how eye movements rather than retinal slip affect balance. They found that slow eye movements increase sway, possibly by an efference copy, which explains why spontaneous nystagmus causes postural imbalance.

Adult↗
PubMed2005

Asymmetric modulation of human visual cortex activity during 10 degrees lateral gaze (fMRI study).

We used BOLD fMRI to study the differential effects of the direction of gaze on the visual and the ocular motor systems. Fixation of a target straight ahead was compared to fixation of a target 10 degrees to the right and 10 degrees to the left from gaze straight ahead, and to eyes open in complete darkness in thirteen healthy volunteers. While retinotopic coordinates remained the same in all fixation conditions, the fixation target shifted with respect to a head-centered frame of reference. During lateral fixation, deactivations in higher-order visual areas (one ventral cluster in the lingual and fusiform gyri and one dorsal cluster in the postero-superior cuneus) and, as a trend, activations in early visual cortical areas were found predominantly in the hemisphere contralateral to the fixation target. We propose that visual processing is performed predominantly in the hemisphere contralateral to gaze direction, even during small gaze shifts into one visual hemifield. The excitability of visual neurons may be modulated depending on eye position to construct a head-centered frame of reference from a retinotopic input, thus allowing perceptual stability of space during eye movements. A further finding was that BOLD signal increases in fronto-parietal ocular motor and attentional structures were more pronounced during lateral than central fixation.

Adult↗
PubMed2005

Thalamic infarctions cause side-specific suppression of vestibular cortex activations.

H2O15-PET was performed during caloric vestibular stimulation of the right and left external ears in eight right-handed patients with acute unilateral infarctions or haemorrhages of the posterolateral thalamus (four right, four left). The posterolateral thalamus is the relay station for ipsi- and contralateral ascending vestibular input to the multiple multisensory vestibular cortex areas. The aim of this study was to evaluate the differential effects of unilateral vestibular thalamic lesions on thalamo-cortical projections, right hemispheric dominance and reciprocal inhibitory visual-vestibular interaction, as well as perceptual and ocular motor consequences during caloric irrigation. The major findings of the group analyses of the patients with right-sided and those with left-sided lesions were as follows: (i) activation of the multisensory vestibular temporo-parietal cortex was significantly reduced in the hemisphere ipsilateral to the thalamic lesion when the ipsilesional or contralesional ear was stimulated; (ii) activation of multisensory vestibular cortex areas of the hemisphere contralateral to the irrigated ipsilesional ear was also diminished; and (iii) the right hemispheric dominance in right-handers described above was preserved in those with right and left thalamic lesions. Simultaneous deactivations were often restricted to only one hemisphere--the one contralateral to the stimulation and contralateral to the vestibular cortex areas activated. There was, however, one area in the inferior insula which was also activated by either right or left ear stimulation in the hemisphere ipsilateral to the lesion. This supports the assumption that there is a bilateral direct ascending vestibular projection from the vestibular nuclei to the inferior part of the insula, which bypasses the posterolateral thalamus and is stronger in the right hemisphere. The cortical asymmetry of the pattern of activation during horizontal semicircular canal stimulation by calorics was not associated with a significant direction-specific asymmetry of caloric nystagmus or perceived body motion. Thus, the data demonstrate the functional importance of the posterolateral thalamus as a unique relay station for vestibular input to the cortex, of the dominance of the right hemisphere in right-handedness, and of ipsilateral ascending pathways. Furthermore, the normal interaction between the two sensory systems--the vestibular and the visual--appears to be impaired.

Adult↗
PubMed2005

Phobic postural vertigo--a long-term follow-up (5 to 15 years) of 106 patients.

One hundred and six patients diagnosed between 1987 and 1998 to have somatoform phobic postural vertigo were examined in a follow-up study with a self-evaluating questionnaire. The improvement rate after a mean follow-up time of 8.5 years (5 to 15.9 years) was 75% (27% of the patients reported a complete remission). While the majority of these patients experienced improvement or remission during the first year after assessment of diagnosis and a short-term psychotherapeutic approach, some patients also had considerable improvement even after two or more years. There was a negative correlation between the duration of the condition before assessment of the diagnosis and the improvement/regression rate. The improvement/regression rate was independent of gender, age, preceding vestibular or non-vestibular organic disorders, and the various medical, physical, or psychotherapeutic interventions. Transient relapses occurred in 47% of the improved patients once or repeatedly. The probability of developing a relapse remained constant throughout the entire follow-up. None of the patients required a revision of the initial diagnosis on the basis of the questionnaire.

Adolescent↗
PubMed2005

[Syncope and epileptic seizures].

Syncope is one of the most common symptoms leading to hospital admission. Thereby syncope can be induced by several diseases. It is crucial to detect underlying structural heart disease or high grade arrhythmias, as these are associated with an increased mortality. The careful history and physical examination can often give sufficient evidence to evaluate the origin of syncope. Additional examinations should only be applied selectively. In patients with structural heart disease the specific treatment should be initiated, in patients with cardiac arrhythmias the implantation of a pacemaker or ICD might be indicated. The most common neurally-mediated and orthostatic syncopes can often be treated successfully by physical training. Beside syncope epilepsy might be responsible for a transient loss of consciousness. Again careful history taking helps to differentiate between these two entities.

Acute Disease↗
PubMed2005

[The effect of combined mitoxantrone and methylprednisolone therapy in primary and secondary progressive multiple sclerosis. An applied study in 65 patients].

Mitoxantrone (mitox) has been shown to be effective for secondary progressive (SP) and relapsing-remitting multiple sclerosis (MS). The aim of this open trial was to evaluate the effects of combined mitox and methylprednisolone (MP) therapy on patients with primary progressive (PP)-MS or with SP-MS. We present here the results of an interim analysis done after the study had lasted 5 years. Sixty-five patients (20 with PP-MS and 45 with SP-MS) have been included so far. The treatment involved ten cycles of combined mitox and MP. The intervals between the individual cycles were systematically prolonged from 3 months initially to 12 months, so the complete treatment took a total of 57 months. Conclusion This interim analysis indicates that mitox combined with MP beneficially reduces the progression of disability in patients with PP-MS and SP-MS. Therefore, this therapy regimen can also be considered a feasible option for PP-MS.

Adult↗
PubMed2005

4-aminopyridine restores visual ocular motor function in upbeat nystagmus.

The effect of the potassium channel blocker 4-aminopyridine (4-AP) on spontaneous upbeat nystagmus (UBN) was investigated with the search coil technique during fixation in different gaze positions and smooth pursuit in a patient before and after ingestion of 10 mg 4-AP. UBN was reduced from 8.6 deg/s to 2.0 deg/s by 4-AP causing subjective relief from distressing oscillopsia, and impaired upward smooth pursuit was restored (gains: before medication 0.38; after medication 0.86). In the dark, UBN was slightly stronger and not affected by 4-AP. We propose that 4-AP improved the function of cerebellar pathways that mediate gaze holding and smooth pursuit by intensifying the excitability of cerebellar Purkinje cells.

4-Aminopyridine↗