Schweizer Archiv für Neurologie und Psychiatrie ... - Sanp.ch

Posters SNS
related fMRI-activity increases were associated with reduced
spasticity; in completely plegic patients, there was no fMRIactivity
change in SII but increased spasticity after training.
Conclusion: Increased activity in SII of contralesional
hemisphere and in MISI of lesioned hemisphere reflect a
treatment-induced effect in the paretic arm. It is hypothesised
that the increased BOLD activity results from increased afferent
information related to the anti-spastic BTX effect reinforced by
training.
92
Effect of Vitamin D on Epstein-Barr (EBV)-specific
CD8+ T cells in patients with early multiple sclerosis (MS)
A.P. Lysandropoulos, E. Jaquiery, S. Jilek, M. Canales,
G. Pantaleo, M. Schluep, Ra Du Pasquier
CHUV, Lausanne, Switzerland
Background: Infection with EBV and a lack in vitamin D may be
important environmental triggers of MS. 1,25-(OH)2D3 mediates
a shift of antigen presenting cells (APC) and CD4+ T cells to a
less inflammatory profile. Although CD8+ T cells do express the
vitamin D receptor, a direct effect of 1,25(OH)2D3 on these cells
has not been demonstrated until now. Since CD8+ T cells are
important immune mediators of the inflammatory response in
MS, we examined whether vitamin D directly affects the CD8+
T cell response, and more specifically if it modulates the EBVspecific
CD8+ T cell response.
Material and methods: To explore whether the vitamin D
status may influence the pattern of the EBV-specific CD8+ T cell
response, PBMC of 10 patients with early MS and 10 healthy
controls (HC) were stimulated with a pool of immunodominant
8-10 mer peptide epitopes known to elicit CD8+ T cell responses.
PBMC were stimulated with this EBV CD8 peptide pool, medium
(negative control) or anti-CD3/anti-CD28 beads (positive
control). The following assays were performed: ELISPOT to
assess the secrection of by T cells in general; cytometric beads
array (CBA) and ELISA togIFN- determine which cytokines
were released by EBV-specific CD8+ T cells after six days of
culture; and intracellular cytokine staining assay to determine by
which subtype of T cells secreted given cytokines. To examine
whether vitamin D could directly modulate CD8+ T cell immune
responses, we depleted CD4+ T cells using negative selection.
Results: We found that pre-treatment of vitamin D had an antiinflammatory
action on both EBV-specific CD8+ T cells and on
CD3/CD28-stimulated T cells: secretion of pro-inflammatory
cytokines (IFN-gamma and TNF-alpha) was decreased, whereas
secretion of anti-inflammatory cytokines (IL-5 and TGF-beta)
was increased. At baseline, CD8+ T cells of early MS patients
showed a higher secretion of TNF-alpha and lower secretion of
IL-5. Addition of vitamin D did not restore the same levels of both
cytokines as compared to HC. Vitamin D-pre-treated CD8+ T
cells exhibited a decreased secretion of IFN-gamma and TNFalpha,
even after depletion of CD4+T cells from culture.
Conclusion: Vitamin D has a direct anti-inflammatory effect on
CD8+ T cells independently from CD4+ T cells CD8+ T cells of
patients with early MS are less responsive to the inflammatory
effect of vitamin D than HC, pointing toward an intrinsic
dysregulation of CD8+ T cells. The modulation of EBV-specific
CD8+ T cells by vitamin D suggests that there may be interplay
between these two major environmental factors of MS.
This study was supported by a grant from the Swiss National
Foundation (PP00P3-124893), and by an unrestricted research
grant from Bayer to RDP.
93
Effects of amygdalo-hippocampal stimulation on
interictal epileptic discharges and synchronization
R. Tyrand 1 , M. Seeck 1 , L. Spinelli 1 , E Pralong 2 , S. Vulliémoz 1 ,
G. Foletti 2 , A.O. Rossetti 2 , C. Pollo 2 , C. Boëx 1
1
University Hospital Geneva, Geneva, Switzerland, 2 Centre
Hospitalier Universitaire Vaudois, Lausanne, Switzerland
Introduction: The objective of the study was to assess the
effects of pulse shape of high frequency deep brain stimulation
(DBS) of the amygdalo-hippocampal complex (AH) on interictal
epileptic discharge rates (IEDRs) and synchronization.
Methods: The effects of AH-DBS implemented with symmetrical
versus asymmetrical biphasic and charge balanced pulses were
evaluated in two different groups of patients: six patients with
hippocampal sclerosis (HS) and six patients with non lesional
(NLES) temporal lobe epilepsy. Synchronization of amygdalohippocampal
and fronto-orbital intracranial EEG, ipsilateral to the
epileptic focus, was computed.
Results: In HS patients, IEDRs were significantly reduced only
with high frequency AH-DBS applied with symmetrical biphasic
pulses. IEDRs were significantly reduced with high frequency
AH-DBS in only two NLES patient, independently of pulse shape.
If high frequency AH-DBS principally induced desynchronization,
IEDRs and synchronization were not correlated.
Conclusions: The decrease of IEDRs suggest that high
frequency AH-DBS could be efficient in HS patients if the
stimulation was applied over a large zone through symmetrical
biphasic pulses; in NLES patients, other individual characteristics
might alter the efficacy of DBS like the localization of the
epileptogenic zone and of the electrode. Comparison to longterm
outcome suggests that IEDRs could be used as a predictor
of chronic AH-DBS, whereas synchronization could not.
94
Effet de la fatigue physique sur la marche des
hémiplégiques
A. Kassouha, L. Allet, I. Feldmann, A. Schnider
Hôpitaux Universitaires de Genève, Genève, Switzerland
Introduction: Chez les sujets hémiplégiques, les paramètres
temporo spaciaux de la marche sont habituellement altérés,
en particulier: la vitesse, la symétrie et la variabilité. Bien que
la fatigue et la baisse de l’endurance soient des symptômes
fréquents dans cette population, nous ne savons pas s’ils
influencent ces paramètres.
Objectifs: Évaluer l’effet de la fatigue physique sur les
paramètres de la marche dans des conditions simples et lors
d’une double tâche.
Méthodes: 26 sujets hémiparétiques hospitalisés pour la
rééducation suite à un accident vasculaire cérébral récent (73
± 32 jours) et capables de marcher sans aide avec/sans moyen
auxiliaire. Les paramètres de la marche ont été enregistrés à
l’aide d’un tapis «GaitRite» de 7,2 m, au début et à la fin d’un
circuit de marche sur un terrain plat. Le périmètre de ce circuit
est déterminé quand l’effort devient difficile (5/10 sur l’échelle de
Borg modifiée). L’enregistrement de la marche se fait à vitesse
confortable avec et sans tâche cognitive de calcul mental.
Résultats: En fin de circuit la vitesse de marche augmente de
54,78 cm/sec (±20.24) à 58.96 cm/sec (±22,9) p = ,05. Cette
augmentation est plus importante dans les conditions de double
tâche, de 43,63 cm/sec (±17,21) à 49,62 cm/sec(±19,79)
p = ,001. L’augmentation de la vitesse se fait par augmentation
de la cadence et de la longueur de l’enjambée. L’asymétrie de
longueur des pas augmente à la fatigue tant lors de la marche
simple [de 5,34 cm (±3,92) à 6,52 cm (±4,90) p = ,05] que lors de
la marche en double tâche [5,96 cm (±5,49) à 8,29 cm (±6,41)
p = ,01]. Le coefficient de variabilité de longueur et de largeur
des pas augmente lors de la marche en double tâche en fin de
circuit. Ceci est significatif par rapport à la marche simple en fin
de circuit et par rapport à la marche en double tâche au début p