www.ksmf.org/arhimed   arhimed@ksmf.org   [5/10/2025 1:28:45 PM] http://www.ksmf.org/arhimed/poglej.asp?id=24 Somatosenzoricni evocirani potenciali pri bolnikih z grafospazmom Avtor: Said Al Mawed, Franc Anderluh Mentor: prof.dr. Tine S. Prevec Somentor: asis.dr. Zvezdan Pirtošek IZHODIŠCA: Grafospazem je žarišcna distonija rok, pri kateri se pri pisanju in vcasih tudi pri sorodnih opravilih pojavijo spazmodicni krci v prizadetih mišicah. Vzroki za to in druge distonije so slabo raziskani. Verjetno je okvarjena motoricna kortiko-subkortiko-kortikalna zanka, ki povezuje bazalne ganglije, talamus in suplementarno motoricno podrocje (SMA). O delovanju SMA lahko sklepamo s pomocjo predcentralnega vala N30 in kompleksa valov P20/N30 somatosenzoricnih izvabljenih odzivov (SEP). Pri ekstrapiramidnih boleznih so amplitude vala N30 spremenjene. Pri parkinsonizmu vecina avtorjev opisuje zmanjšane amplitude vala N30, pri distonijah pa nekateri povecane, drugi zmanjšane amplitude Pri veliki vecini raziskav so snemali SEP po elektricnem draženju, le redko so uporabili tudi mehansko draženje. Meritve pri bolnikih z multiplo sklerozo so pokazale, da z mehansko izvabljenimi SEP verjetno prej odkrijemo predklinicne motnje. NAMEN: V raziskavi smo poskušali odkriti, ali lahko z merjenjem vala N30 oziroma kompleksa valov P20/N30 SEP pri bolnikih z grafospazmom ugotovimo kaj o mehanizmu bolezni in ali obstajajo razlike v obcutljivosti med SEP po elektricnem in mehanskem draženju. METODE: V raziskavo smo vkljucili 10 bolnikov z grafospazmom in 8 zdravih prostovoljcev. Izmerili smo jim SEP po elektricnem draženju medianega živca in mehanskem draženju palceve mišicne kepe. REZULTATI: Pri bolnikih z grafospazmom smo odkrili manjhno amplitudo kompleksa valov P20/N30. Pri elektricno izvabljenih SEP je bila amplituda v primerjavi z zdravimi preiskovanci zmanjšana tako na zdravi kot na bolni roki, pri mehansko izvabljenih pa le na bolni roki. Rezultati med bolno in zdravo roko se ne razlikujejo statisticno znacilno. S primerjavo elektricno in mehansko izvabljenih SEP smo ugotovili, da so latence po mehanskem draženju daljše kot po elektricnem, medtem ko se amplitude ne razlikujejo statisticno znacilno. ZAKLJUCKI: Manjše amplitude kompleksa valov P20/N30 pri bolnikih z grafospazmom odražajo zmanjšanje aktivnosti v SMA, kar je verjetno posledica okvare v neposredni poti motoricne kortiko-subkortiko-kortikalne zanke. Zmanjšanje amplitude kompleksa valov P20/N30 pri bolnikih z grafospazmom je enako na obeh rokah, tako zdravi kot bolni. Iz tega lahko sklepamo, da je okvara obojestranska. Elektricno izvabljeni SEP omogocajo odkrivanje motenj v bazalnih ganglijih, ko le te niso klinicno izražene. «» [Abstract / English version] Somatosensoric evoked potentials in patients with writer's cramp Author: Said Al Mawed, Franc Anderluh Mentor: prof.dr. Tine S. Prevec Co-mentor: asis.dr. Zvezdan Pirtošek INTRODUCTION: Writer's cramp is a focal dystonia of hands. While writing or performing similar tasks spasmodic cramps in affected muscles appear. Causes for this and other dystonias are poorly understood. Probably the motoric cortico-subcortico-cortical loop which connects basal ganglia, thalamus and supplementary motor area (SMA) is damaged. We can get some information about the function of the SMA by studying the prerolandic wave N30 and the P20/N30 complex of somatosensory evoked potentials (SEPs). Amplitudes of the N30 wave are altered in extrapiramidal diseases. Most authors describe smaller amplitudes of the N30 wave in parkinsonism, whereas in dystonias they found smaller or bigger amplitudes. Usually electrical SEPs were used, but in the study with the group of patients with multiple sclerosis it was found that with mechanical SEPs preclinical disturbances could be detected earlier. PURPOSE: In our research we tried to find out if we can learn about the mechanism of the disease by measuring the wave N30 and the P20/N30 complex of SEP in the group of patients with writer's cramp, and if there is a difference in the sensitivity between electrical and mechanical SEPs. METHODS: 10 patients with writer's cramp and 8 healthy volunteers took part in our study. SEPs were measured after electrical stimulation of the median nerve and after mechanical stimulation of the thenar. RESULTS: Patients with writer's cramp had smaller amplitudes of P20/N30 complex than healthy volunteers. After electrical stimulation the amplitude of P20/N30 complex was smaller on both the affected and the unaffected hand, whereas after mechanical stimulation the amplitude of P20/N30 complex was smaller only on the affected hand. There was no difference between the affected and the unaffected hand. Comparison between the electrical and the mechanical SEPs showed that latency of the N30 wave was longer after mechanical stimulation. There was no difference in the amplitude. CONCLUSIONS: Smaller amplitude of P20/N30 complex in patients with writer's cramp is the result of lower activity in the SMA, which is probably caused by the damage somewhere in the direct pathway of motoric cortico-subcortico-cortical loop. In the group of patients amplitude was smaller on both hands - the affected and the unaffected, so the damage in central nervous system is probably bilateral. Electrical SEPs allows us to find damage in the basal ganglia before it is clinically expressed.