Biomedical subjects

J Bednarík

Publications and source records attributed to J Bednarík.

At least 19 recordsLinked to original sources

PubMed1990

Site of motor pathway excitation during cervical spinal stimulation.

In a set of 25 normal subjects the probable site of activation of the motor pathway was looked for using transcutaneous cervical spinal stimulation. The motor conduction time in the fastest fibres between the "spinal cord" and the wrist reached 10.79 (SD 1.17) ms when using this technique and this value was compared to the same parameter obtained with other methods: F wave mean conduction time in the established distance was 11.0 (SD 0.96) ms; the conversion of sensory to motor conduction showed 11.0 (SD 1.1) ms and H wave 10.97 (SD 1.03) ms. The conduction time through the fastest motor fibres with the spinal stimulation corresponds to the activation of the alpha-motoneuron axons near their bodies. When interpreting the results of the cortical and spinal stimulation, it is necessary to take this fact into account.

Adult↗

PubMed1990

[Evoked motor potentials in the diagnosis of multiple sclerosis].

The authors examined evoked motor potentials (MEP) of the upper extremities in a group of 43 patients with multiple sclerosis using transcranial cortical and spinal stimulation. As abnormal they rated a prolongation of the motor conduction time by more than 3 sigma above the mean value recorded in the control group or when the response could not be evoked. The central motor conduction time between the cortex and cervical spine was abnormal in 76.7% of patients. The authors did not find a correlation between the severity of the paresis and the degree of electrophysiological abnormality. In frust and mild pareses the sensitivity was 80%. The frequency of abnormalities correlated with the degree of the diagnostic certainty. In patients with a probable diagnosis (according to Poser) abnormalities were present in 41.6%, when the diagnosis was certain, in 90.3%. In prolongation of the time of central motor conduction among all abnormalities 65.1% were due to prolonged motor conduction and in 27.9% the response could not be evoked. MEP examination is a sensitive technique for the detection of clinical and subclinical lesions and as to its sensitivity it is better than visual EP.

Adult↗

PubMed1990

[Somatosensory evoked potentials in the diagnosis of multiple sclerosis].

The authors examined SEP in a group of 54 patients with the clinical diagnosis of SM. The sensitivity of the test in SEP of the median nerve was 68%, in SEP of the tibial nerve 78%. Concurrent use of both techniques revealed an abnormality in 83%. Subclinical abnormalities were present in 28% (median nerve) and 24% resp. (tibial nerve) of the patients. In case of a clinical disturbance of sensitivity the SEP finding was normal in 10% of the patients. A typical abnormality in SM was the absence of spinal responses and prolongation of the central conduction time. In 41% of the patients with an abnormal finding the abnormality was unilateral. The authors discuss possibilities of topical diagnosis of sensitive lesions by means of SEP.

Adolescent↗

PubMed1989