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Neurophysiological evidence of cortical plasticity in patients with facial palsy
Society proceedings were investigated, however. There was no exact differentiation of central and obstructive apneas. Twenty patients (17 men, 3 women, mean age 53.9 _+2.1 years) with severe OSAS (apnea/hypopnea-index, 34.2 _+ 14. l/h; part of O2-saturation <90% during sleep (SaO 2 < 90%), 13.5 _+ 42%,; minimal nocturnal O2-saturation, 78.0 + 2.5%7 were examined before starting nCPAP-therapy. BAEP were elicited after applying clicks 70 dB above threshold to each ear. Means of wave latencies 1, 11, Ill, IV, V as well as interpeak latencies (I-V, l-III, Ill-V) were delayed significantly compared to normal controls. Main prolongations were seen regarding wave latency l (P < 0.0017 and interpeak latency I-V (P < 0,001 I, Prolongation of interpeak latencies (mean _+2.5 SD7 of one or two sides could be demonstrated in 12 of 20 patients. Pontomesencephal lesions t9 patients) dominated. There was no connection with respiratory' parameters. However. pathological BAEP changes correlated with the duration of the disease. Pathological BAEP indicating brainstem lesions were seen in 60% of the examined OSAS-patients. Mesencephal lesions dominated; number of lesions increased with duration of disease. Therefore, pathological findings should not be considered as a cause but as a result of hypoxemia in OSAS. Pathological BAEP may reveal a higher risk for cerebrovascular stroke. Therefore. these patients should be investigated further cerebrovascu
larly 48.
Excitatory and inhibitory effects of transcranial magnetic cortex stimulation with different current directions. - A. Kuehn, S. Roericht, B.-U. Meyer (Department of Neurology, Charit6, Berlin)
Previous investigations had shown that the amplitude :md latency of lmnscranially elicited, corticospinally mediated motor responses vary with different directions of the induced currents. The question arose whether the parameters of caliosally mediated interhemispheric inhibition also change with different current directions. Transcranial magnetic stimulation was performed with a focal 8-shaped coil (Magstim 200) in 9 healthy w)luntecrs with an intensity of 60% max. over the hand motor cortex and 8 directions of induced currents (rotation of tile coil axis in steps of 45"). Surface EMG-rcsponses were recorded bilaterally from the maximally tonically contracted first dorsal interosseus muscle Contra- and ipsilateral stimulation effects were maximal with currents flowing perpendicular across the motor strip, i.e. posteroanlerlorly and lateromedially (45" oblique towards the midline). Currents flowing lateromedially along the motor strip had mininml stimulation effects In accordance with direct activation of corticospinal fibres via lateromedial currents, the onset latencies of the contralateral excitatory responscs were shortest for this direction. This was not observed for Ihe latency of transcallosal inhibition. The resuhs could bc explained by a transcranial activation of interneurones which activate corticospinal and callosal cortical cells indirectly. Furthermore, additional direct activa lion of corticospinal neurons might occur under some conditions
49.
Ncurophysiological evidence of cortical plasticity in patients with facial palsy. - J. Liepert a. M. Tegenthotl ~a, M. Riintjcs b, S. Kotterba a, C. Weiller b, J.-P. Malin a (aNeurologische Kliuik und Poliklinik der Ruhr-Universitiit, Bochum; bNeurologische ! niversitiitsklinik, Essen)
Molor cortex representation areas of different inuscles, as dctermined by l\3cal lranscranial magnetic stimulation (TMS), may increase after perl'ormmg skilled motor tasks or may decrease during king tcrm immobilizalinn We studied the motor corlex area of a small hand muscle in patients with facial palsy in order to delermine whether changes of mva size occur. Eight patients with a peripheral facial palsy tduramm: 29 days to 36 years) were studied. The cortical represcntatmn area oi tile abductor pollicis brews muscle (APB) was mapped over both hemispheres m steps of i cm using focal TMS with a stimulus intensity of 12()'7~ motor threshold. The representation area ¢lf the APB was sJgnil)cantly enlarged ovcr the hemisphere conlralatcrai to lhe
49P
facial palsy, extending into a lateral direction. In addition, the sum of amplitudes and the volume of the area were increased compared to the area ipsilateral to the facial palsy. This study demonstrates that the representation area of a hand muscle increases and expands into the cortical face muscle representation in patients with a facial palsy. Possible underlying mechanisms might be a reduction of GABAergic intracortical inhibition or axonal sprouting. 50.
Validity of neuruphysiology and ncuroradiology in punsaffections with special presentation of central pontine myelinnlysis (CPM). - H. Menger (Neurologische Klinik der Universitiit Witten Herdeeke, Klinikum Wuppertal, Wnppertal)
While the relevance of evoked potentials, brain stem reflexes and imaging procedures for the diagnosis and prognosis of vascular punsdiseases has been underscored, no similar evaluation of these procedures for CPM has been undertaken in case reports up until now. The goal of our examinations in 18 own and 20 secured CPM-paticnts of a recent study was the retrospective evaluation of diagnostic and prognostic validity of ncurophysiological (FAEP, ()OR, medianus-/tibialisSEP, MEP, in individual cases masseter-reflex, trigeminus-SEP, PAP) and neurological (CCT, MRI, in individual cases PET) procedures in CPM Our results verify the essential diagnostic value of history and clinical manifestations in the initial phase of acute CPM when it lacks typical neurophysiological and neuroradiological patterns. In early diagnosis of CPM, cerebral MRI is superior to CCT. Nonetheless, no conclusions can be drawn on the basis of MRI morphology with respect to extent anti course of clinical deficits, which normally have good remission despite persisting MRl-deficits. Single cases of neurophysiological pathology did not correlate with clinical evidence nor with imaging procedures and in general improved during the course of the illness. In sun-nnary, the low correlation between neurophysiology, neuroradiology and the clinical course of CPM may be explained as a functional disorder. Even at the peak of acute CPM development, there is most likely only partial demyelinisation in the region of myelinolysis despite intact neurons anti axons.
51.
Propcnfofylline prevents deterioration of EEG-power in the course of primary-degenerative and vascular dementia. - R. Mielke a, B. Szelies a, J. Kessler a, M. Rother b, W.D. Heiss a (aMax-Planck Institut fiir Neurologischc Forschung, D-50931 K61n; bHoechst AG, Werk Kalle-Albert, Kliniscbe Forscbung, Wiesbaden7
Propentofylline (HWA 285, Hoechst AG) is a novel compound that blocks reuptake of adenosine by neurons and gila cells and inhibits phnsphodiesterase of cyclic adenosine monophosphate. The pharmacological profile of propentofylline includes neuroprotectivc and bloodflow improving properties. In a double-blind, placebo-controlled trial in 30 patients with vascular dementia (VD) according to DSMqlI-R criteria and 30 patients with AIzheimer's disease according to NINCDSADRDA criteria, we analyzed the effects of propentofylline on EEGpower. Propentofylline was applied in the form ot a 300 mg tablet 3 times a day. EEG was recorded under resting conditions with eyes closed using an online 19-channel EEG system
larly 48.
Excitatory and inhibitory effects of transcranial magnetic cortex stimulation with different current directions. - A. Kuehn, S. Roericht, B.-U. Meyer (Department of Neurology, Charit6, Berlin)
Previous investigations had shown that the amplitude :md latency of lmnscranially elicited, corticospinally mediated motor responses vary with different directions of the induced currents. The question arose whether the parameters of caliosally mediated interhemispheric inhibition also change with different current directions. Transcranial magnetic stimulation was performed with a focal 8-shaped coil (Magstim 200) in 9 healthy w)luntecrs with an intensity of 60% max. over the hand motor cortex and 8 directions of induced currents (rotation of tile coil axis in steps of 45"). Surface EMG-rcsponses were recorded bilaterally from the maximally tonically contracted first dorsal interosseus muscle Contra- and ipsilateral stimulation effects were maximal with currents flowing perpendicular across the motor strip, i.e. posteroanlerlorly and lateromedially (45" oblique towards the midline). Currents flowing lateromedially along the motor strip had mininml stimulation effects In accordance with direct activation of corticospinal fibres via lateromedial currents, the onset latencies of the contralateral excitatory responscs were shortest for this direction. This was not observed for Ihe latency of transcallosal inhibition. The resuhs could bc explained by a transcranial activation of interneurones which activate corticospinal and callosal cortical cells indirectly. Furthermore, additional direct activa lion of corticospinal neurons might occur under some conditions
49.
Ncurophysiological evidence of cortical plasticity in patients with facial palsy. - J. Liepert a. M. Tegenthotl ~a, M. Riintjcs b, S. Kotterba a, C. Weiller b, J.-P. Malin a (aNeurologische Kliuik und Poliklinik der Ruhr-Universitiit, Bochum; bNeurologische ! niversitiitsklinik, Essen)
Molor cortex representation areas of different inuscles, as dctermined by l\3cal lranscranial magnetic stimulation (TMS), may increase after perl'ormmg skilled motor tasks or may decrease during king tcrm immobilizalinn We studied the motor corlex area of a small hand muscle in patients with facial palsy in order to delermine whether changes of mva size occur. Eight patients with a peripheral facial palsy tduramm: 29 days to 36 years) were studied. The cortical represcntatmn area oi tile abductor pollicis brews muscle (APB) was mapped over both hemispheres m steps of i cm using focal TMS with a stimulus intensity of 12()'7~ motor threshold. The representation area ¢lf the APB was sJgnil)cantly enlarged ovcr the hemisphere conlralatcrai to lhe
49P
facial palsy, extending into a lateral direction. In addition, the sum of amplitudes and the volume of the area were increased compared to the area ipsilateral to the facial palsy. This study demonstrates that the representation area of a hand muscle increases and expands into the cortical face muscle representation in patients with a facial palsy. Possible underlying mechanisms might be a reduction of GABAergic intracortical inhibition or axonal sprouting. 50.
Validity of neuruphysiology and ncuroradiology in punsaffections with special presentation of central pontine myelinnlysis (CPM). - H. Menger (Neurologische Klinik der Universitiit Witten Herdeeke, Klinikum Wuppertal, Wnppertal)
While the relevance of evoked potentials, brain stem reflexes and imaging procedures for the diagnosis and prognosis of vascular punsdiseases has been underscored, no similar evaluation of these procedures for CPM has been undertaken in case reports up until now. The goal of our examinations in 18 own and 20 secured CPM-paticnts of a recent study was the retrospective evaluation of diagnostic and prognostic validity of ncurophysiological (FAEP, ()OR, medianus-/tibialisSEP, MEP, in individual cases masseter-reflex, trigeminus-SEP, PAP) and neurological (CCT, MRI, in individual cases PET) procedures in CPM Our results verify the essential diagnostic value of history and clinical manifestations in the initial phase of acute CPM when it lacks typical neurophysiological and neuroradiological patterns. In early diagnosis of CPM, cerebral MRI is superior to CCT. Nonetheless, no conclusions can be drawn on the basis of MRI morphology with respect to extent anti course of clinical deficits, which normally have good remission despite persisting MRl-deficits. Single cases of neurophysiological pathology did not correlate with clinical evidence nor with imaging procedures and in general improved during the course of the illness. In sun-nnary, the low correlation between neurophysiology, neuroradiology and the clinical course of CPM may be explained as a functional disorder. Even at the peak of acute CPM development, there is most likely only partial demyelinisation in the region of myelinolysis despite intact neurons anti axons.
51.
Propcnfofylline prevents deterioration of EEG-power in the course of primary-degenerative and vascular dementia. - R. Mielke a, B. Szelies a, J. Kessler a, M. Rother b, W.D. Heiss a (aMax-Planck Institut fiir Neurologischc Forschung, D-50931 K61n; bHoechst AG, Werk Kalle-Albert, Kliniscbe Forscbung, Wiesbaden7
Propentofylline (HWA 285, Hoechst AG) is a novel compound that blocks reuptake of adenosine by neurons and gila cells and inhibits phnsphodiesterase of cyclic adenosine monophosphate. The pharmacological profile of propentofylline includes neuroprotectivc and bloodflow improving properties. In a double-blind, placebo-controlled trial in 30 patients with vascular dementia (VD) according to DSMqlI-R criteria and 30 patients with AIzheimer's disease according to NINCDSADRDA criteria, we analyzed the effects of propentofylline on EEGpower. Propentofylline was applied in the form ot a 300 mg tablet 3 times a day. EEG was recorded under resting conditions with eyes closed using an online 19-channel EEG system