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Biomedical subjects

Peter P Urban

Publications and source records attributed to Peter P Urban.

7 recordsLinked to original sources
PubMed2005

Clinical and neuroradiological spectrum of isolated cortical vein thrombosis.

BACKGROUND: Isolated cortical vein thrombosis is only rarely diagnosed, although it may commonly be overlooked. RESULTS: We report on four patients with this diagnosis who all presented with focal sensorimotor seizures. The diagnosis was made by a typical CT and MRI-pattern, which is described in detail. CONCLUSIONS: The prognosis was excellent in all patients and the treatment options are discussed.

Aged↗
PubMed2005

Somatotopic organization of the corticospinal tract in the human brainstem: a MRI-based mapping analysis.

To investigate the incompletely understood somatotopical organization of the corticospinal tract in the human brainstem, we performed a voxel-based statistical analysis of standardized magnetic resonance scans of 41 prospectively recruited patients with pyramidal tract dysfunction caused by acute brainstem infarction. Motor hemiparesis was rated clinically and by the investigation of motor evoked potentials to arms and legs. Infarction affected the pons in 85% of cases. We found the greatest level of significance of affected brainstem areas between the pontomesencephalic junction and the mid pons. Lesion location was significantly more dorsal in patients with hemiparesis affecting more proximal muscles and was significantly more ventral in patients with predominantly distal limb paresis. Comparison of magnetic resonance lesion from patients with paresis predominantly affecting arm or leg did not show significant topographical differences. We conclude that a topographical arm/leg distribution of corticospinal fibers is abruptly broken down as the descending corticospinal tract traverses the pons. Corticospinal fibers, however, follow a somatotopical order in the pons with fibers controlling proximal muscles being located close to the reticular formation in the dorsal pontine base, and thus more dorsal than the fibers controlling further distal muscle groups.

Adult↗
PubMed2002

Electrophysiological brainstem testing in the diagnosis of reversible brainstem ischemia.

The aim of this study was to evaluate the sensitivity of multimodal electrophysiological brainstem testing in the diagnosis of clinically suspected reversible ischemic deficits of the brainstem compared with diffusion weighted MR imaging. We investigated 158 consecutive patients presenting with signs of acute brainstem dysfunction. Serial electrophysiological brainstem tests including masseter reflex, blink reflex, masseter inhibitory reflex, AEP, MEP, EOG and the oculoauricular phenomenon were applied. In 14 of the 158 patients neurological deficits resolved in less than 24 hours, which was suggestive of a transitory ischemic attack (TIA), 19 patients had brainstem signs for more than 24 hours but less than 1 week, suggestive of a reversible ischemic neurological deficit (RIND). Electrophysiological data indicated acute functional brainstem lesions in 54,5 % of patients with transient clinical brainstem impairment. Lesion detection rate was significantly higher when combining electrophysiological data and MRI (60,4 %) than using acute brainstem abnormalities in diffusion weighted MRI alone (39,4 %). We conclude that diffusion weighted MRI and electrophysiological brainstem testing are complimentary sensitive indicators of acute brainstem lesions in patients with reversible neurological deficits. Correct identification of brainstem ischemia influences the therapeutic regimen and may improve patient outcome.

Adult↗
PubMed2002

Seventh nerve palsies may be the only clinical sign of small pontine infarctions in diabetic and hypertensive patients.

BACKGROUND: Small brainstem infarctions are increasingly recognized as a cause of isolated ocular motor and vestibular nerve palsies in diabetic and/or hypertensive patients. This raises the question whether there are also isolated 7(th) nerve palsies due to pontine infarctions in patients with such risk factors for the development of cerebrovascular diseases. METHODS: Over an 11-year-period, we retrospectively identified 10 diabetic and/or hypertensive patients with isolated 7(th) nerve palsies and electrophysiological abnormalities indicating pontine dysfunction. All patients had examinations of masseter and blink reflexes, brainstem auditory evoked potentials, direct current electro-oculography including bithermal caloric testing, and T1- and T2-weighted MRI (slice thickness: 4-7 mm). RESULTS: Electrophysiological abnormalities on the side of the 7(th) nerve palsy included delayed masseter reflex latencies (4 patients), slowed abduction saccades (4 patients), vestibular paresis (2 patients), and abnormal following eye movements (2 patients). Electrophysiological abnormalities were always improved or normalized at re-examination, which was always associated with clinical improvement. MRI revealed an ipsilateral pontine infarction in 2 patients. Another 2 had bilateral hyperintense intrapontine lesions, and one an ipsilateral cerebellar infarction. CONCLUSIONS: Simultaneous improvement or recovery of abnormal clinical and electrophysiological findings strongly indicated that both were caused by the same actual pontine lesions. A 7(th) nerve palsy may be the only clinical sign of a pontine infarction in diabetic and/or hypertensive patients. Such mechanism may be underestimated if based on MRI only.

Adult↗