tDCS, epilepsy

1. Transcranial direct current stimulation
as a treatment option in CSWS
-preliminary results
Edina Varga
Danish Epilepsy Center, Dianalund, Denmark
2010.

2. Introduction
 Transcranial direct
current stimulation (tDCS)
 Continuous Spikes-and-Waves
during Slow-wave Sleep (CSWS)
Study
 The aim of the study
 Materials and methods
 Results
 Conclusions

3. A.C. 43. Scribonius Largus 1755, Charles Le Roy
Electric torpedo fish Pain relief and eliciting
phosphene
1855, Duchenne de Boulogne
L’Electrisation Localisee
Pascual-Leone&Wagner
Ann Rev Biomed Eng 2007; 9:527-565.
Transcranial direct current stimulation
- historical background

4. Spontaneous neuronal discharge can be modulated
by direct current in a polarity-dependent way
Creutzfeldt et al;
Exp Neurology 1962; 5:436-452.
basic
neuronal
activity
anodal
stimulation
cathodal
stimulation
Transcranial direct current stimulation
Terzuolo&Bullock
Proc NAS USA 1956; 42:687-694.

5.  Cathodal stimulation → hyperpolarisation of neuronal
membranes → decreases cortical excitability
 Anodal stimulation → depolarisation → increased cortica
excitability
Bindman et al; Nature 1962; 196:584-585.
Priori et al; Neuroreport 1998; 9:2257-2260.
Nitsche&Paulus J Pysiol 2000; 527(3):633-639.
Transcranial direct current stimulation
The effect depends on:
Current intensity
Current density
Stimulus duration
Anatomical structures
After-effect (AE) depends on:
Current intensity
Stimulus duration

6. Transcranial direct current stimulation
-safety studies
 animal and human studies
 se NSE-level, temperature
 MRI, PET, BOLD-fMRI
 SEP/VEP/EEG, TMS – MEP
 Retrospective study about side-effects: 102 objects, 567 sessions
(75.5% healthy, 8.8% migraine, 5.9% post-stroke, 9.8% tinnitus)
Non-specific adverse effects:
 paraesthesia (70.6%)
 fatigue (11.8%)
McCreery IEEE Trans Biomed Eng 1990;37:996-1000,
Baudewig et al. Mag Res Med 2001.45:196-201,
Poreisz et al; Brain Res Bull 2007; 72:208-214.
No epileptic seizures!
vomitus
(2.9%)
insomnia
(0.98%)

7. CSWS
 idiopathic childhood
epilepsy
 continuous epileptiform
discharges during sleep
 neurocognitive decline
 behavioural dysfunctions
 epileptic seizures
 limited therapeutic
approaches
M S-de-Boer Epilepsia 2009; 50(7):13-17.

8. tDCS and epilepsy
Cathodal tDCS has an anticonvulsive
effect.
The effect depends on stimulus
duration and current strenght
(100 uV; 60 min→120 min after-effect).
Neither morphologic nor
immunohistochemical changes in the rat
brains after tDCS.
19 patients with focal cortical dysplasia
and AED-resistent focal epilepsy.
Cathodal tDCS (1 mA, 20 min) →
significant reduction in epileptic discharges
on EEG and decrement of seizure
frequency, possibly via decrement of
cortical excitability.
Cathodal tDCS does not induce seizure.

9.  The aim of the study
 to detect the possible therapeutic effect of cathodal
tDCS on the epileptiform EEG discharges (BESA)
 neuropsychological tests (if positive effect on EEG)
 Materials and methods
 Subjects: CSWS patients (age>5 years) were recruited (10/3)
 tDCS:
 cathodal tDCS (1.0 mA, 20 min) over the focus
 current density: 30 µA/ cm2
 electrodes: 0,9% NaCl (35 cm2)
 control stimulation = sham stimulation
 Protocol:
 1.Night: EEG + sham
 2.Night: EEG + cathodal tDCS
 3.Night: if >50% reduction: 2 more sessions with
cathodal tDCS + neuropsychological testing Stimulator: Neuro Conn GmbH,
Ilmenau, Germany
BESA – Brain Electrical Source Analysis

10.  Data analysis:
 The effect of tDCS was measured on EEG, by
quantifying the percentage of non-REM sleep
containing spike-and-slow-waves.
 Results
 There was no detectable effect of tDCS on
CSWS activity on EEG in two children.
 Spike-and-slow wave activity disappeared after
sham stimulation in the third patient.

11. Conclusions
tDCS
 non-invasive, painless stimulation technique
 follow-up with EEG
 well-tolerated among children with CSWS
 reversible effect
 reproducible
 unexpensive
 potential therapeutic usage:
epilepsy
pain
dystonia
poststroke rehabilitation
Further patients recruitment is needed to draw a reliable
conclusion on the efficacy.

12. Acknowledgement
Patients and their parents
Daniella Terney,
Marina Nikanorova, Mary Atkins,
Ditte Sofie Jeppesen, Helle Hjalgrim,
Lone Sand, Sándor Beniczky