[Magnetic stimulation of the motor cortex in healthy persons]. / Magnetna stimulacija motornog korteksa kod zdravih ispitanika.

In 49 healthy volunteers the motor cortex was stimulated transcranially by the intensive short magnetic field and the responses of the m. abductor digiti minimi (m. ADM) in 20 volunteers were recorded and of the m. tibialis anterior (m. TA) in 29 volunteers in relaxation and in mild contraction. In all volunteers by the electric stimulation of the ulnar nerve in the region of the wrist and the peroneal nerve in the region of the fibular capitulum there have been measured the F wave latency, distal latency of M responses and the conduction time of the peripheral motor neuron has been calculated. The difference between the latency of m. ADM and n. TA responses and the conduction time of the peripheral motor nerve represented the central motor conduction time from the motor cortex to the motor neurons of the anterior horns of the spinal cord (C8 and L4 segments). The normative values of the absolute latencies of the muscle responses and the central motor conduction time in the relaxed and contracted muscle are calculated as well as the normatives of the normal differences in latencies and the central motor conduction time between the left and right side of the same subject.

[Multimodal evoked potentials and the blink reflex in patients with primary brainstem lesions]. / Multimodalni evocirani potencijali i blink-refleks u pacijenata sa primarnom lezijom mozdanog stabla.

In 17 patients with primary brainstem injury, out of 60 patients with severe head trauma, diagnostic and prognostic values of multimodal evoked potentials and blink reflex were evaluated in relation to clinical syndromes of the brainstem, the duration of coma and the outcome. Clinical classification of the brainstem syndromes according to Gerstenbrand and Rumpl was used for the evaluation of the clinical findings, the Innsbruck Coma Scale (ICS) for the evaluation of the coma level, and the Glasgow Outcome Scale (GOS) for the outcome. Analyses and measurements of the multimodal evoked potentials and blink reflex were used many times in the period of assessment (six months after the injury). The analysis of our results with multimodal evoked potentials and blink reflex revealed different correlation and sensitivity in relation to the clinical syndromes of the brainstem, the duration of coma and the outcome of the injury. The blink reflex and somatosensory evoked potentials had the best correlation and the greatest sensitivity, the auditory evoked potentials had somewhat, while the visual evoked potentials had none. Multimodal evoked potentials and blink reflex increase the specificity of the diagnosis of brainstem injury compared to clinical observation only, and improve prognostic reliability.

Somatosensory evoked potential monitoring during intracranial surgery.

In the neurosurgical approach to intracranial aneurysms which are often accompanied by arterial spasm and cortical ischaemia, monitoring procedures aim to obtain useful information on cerebral function. SEPs evoked by stimulation of the median nerve at the wrist and of the tibial nerve at the medial malleolus were registered in 45 patients with intracranial aneurysms during neurosurgical procedures. Our results show SEP abnormalities during different stages of neurosurgical procedures in 36 patients out of the monitored 45. Significant abnormalities of SEPs with respect to the control group were decrease of the amplitude of N 20-P 25 complex, lengthening of the absolute latency of the waves N 20- and P 25 and lengthening of the central conduction time (CCT) (N 13-N 20). The greatest SEP abnormalities were registered during the neurosurgical approach to aneurysm and during the clipping procedure. However, the changes were reversible in the majority of the patients. The aim of this paper was to focus on early detection of some cerebral function disturbances during the neurosurgical procedure as well as the prevention of possible brain damage.