1. Georg-August-University, Dept. Clinical Neurophysiology
Transcranial direct current stimulation for improvement of motor and sensory functions
Michael A. Nitsche
Georg-August-University, Dept. Clinical Neurophysiology
Göttingen

2. Motor cortex excitability increase after anodal stimulation
Nitsche & Paulus 2001

3. Motor cortex excitability decrease after cathodal tDCS
1.2
1.0
0.8
0.6
0.4 1 5 10 15 20 25 30 35 40 45 50 55 60 90
120 min
Nitsche et al. 2003

4. Mechanism of action of tDCS - the cellular perspective
Na, Ca Ca
NMDA Ca
GLU
AMPA
AMPA
GABA DA
ACh
Serotonine
???????

5. Similarities to motor learning

6. Imaging - PET Initial learning Consolidation Honda et al. 1998
Learning: left sensory-M1
Consolidation: sma, right premotor, parietal
Post links, ant rechts
Honda et al. 1998

7. Cortical excitability - TMS
Pascual-Leone et al. 1994

8. Can a further enhancement of motor cortex excitability by tDCS improve motor function?

9. Sequence of 12 items, repeated 10 times per block
Functional effects of motor cortex tDCS: Implicit motor sequence learning
Sequence of 12 items, repeated 10 times per block

10. Procedure Sequence Random block Task routine Sequence learning
Sequence learning effect

11. tDCS over M1during learning
anodal
cathodal
non
Reaction time vs baseline
Nitsche et al. 2003

12. Application in stroke - reduction of maladaptive cortical plasticity
Intervention

13. Therapeutic options
Physiotherapie
Hirnstimulation

14. Therapeutic Options II

15. Application in stroke: tDCS reduces motor deficits
Hummel et al. 2005
Fregni et al. 2005

16. Application in stroke II: repeated tDCS induces cumulative effects
Fregni et al. 2007

17. Open questions When to stimulate? Where to stimulate?
How strong to stimulate?
What repetition interval?
Which drugs are allowed?
...

18. When to stimulate I Abhängigkeit der Modulation vom Kalziumeinstrom?
Versuchsablauf I
Sequence
Random block
tDCS
Routine learning
Sequence learning
Effect of sequence learning
Abhängigkeit der Modulation vom Kalziumeinstrom?
Kuo et al. 2008

19. Jakoubkova et al., in preparation
When to stimulate II
Jakoubkova et al., in preparation

20. Where to stimulate
Vines et al. 2008

21. What repetition interval I
Monte Silva et al., in preparation

22. What repetition interval II
The learning curve for the sham (white diamonds) and anodal (gray squares) tDCS groups for the 30 training blocks over 5 days
Sequential visual isometric pinch task
Retention of skill
Reis J. et.al. PNAS 2009;106:

23. Improvement of visual functions by the same rationale I
Antal et al. 2003, 2004

24. Transfer to hemianoptic patients post stroke
ipsilateral
contralateral
prä post post2
Nitsche et al., in Vorbereitung

25. Perspectives
Current pilot studies: proof of principle of efficacy of tDCS to treat deficits after stroke
Future studies should encompass optimizing efficacy, most probably by combination of stimulation and cognitive/physiotherapy
Safety and electrophysiological studies are needed to learn about maximum effective and safe protocols

26. Any Questions?