Y P Behavioral Intervention Research Using tDCS Plasticity O - - PDF document

Berenson-Allen Center for Noninvasive Brain Stimulation Beth Israel Deaconess Medical Center Harvard Medical School

Behavioral Intervention Research Using tDCS

Dylan J. Edwards PhD

Director, Moss Rehabilitation Research Institute, Philadelphia Professor of Neuroscience, ECU Australia

Plasticity

Adaptive Maladaptive

Promoting useful plasticity in motor cortex Patient Intervention Patient + Intervention

Robotics for assessment of performance kinematics

Pre – training Post - training

TMS Demonstration !"#$

P L E A S E D O N O T C O P Y

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Corticomotor excitability in stroke

Webster et al (2006) Webster et al (2006)

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IMPROVED CORTICOMOTOR OUTPUT FROM IPSI-LESIONAL M1 & IMPROVED MOTOR BEHAVIOUR

Webster et al (2006) Webster et al (2006)

Functional Improvements sRT/cRT Pinch force acceleration fingers/thumb AROM Movement accuracy Purdue Pegboard JTT TMS correlates Resting MT Transcallosal Inhibition MEP Amplitude

IMPROVED CORTICOMOTOR OUTPUT FROM IPSI-LESIONAL M1 & IMPROVED MOTOR BEHAVIOUR

P L E A S E D O N O T C O P Y

Butler et al.

Anodal tDCS favors clinical improvement in stroke…

How does repetitive behavior affect motor cortex?

Simple repetitive finger movements increase excitability Motor map does not change unless in skill context

P L E A S E D O N O T C O P Y

How does combined intervention affect motor cortex?

Nitsche et al (2007)

Anodal tDCS prior to excitatory PAS further boosts excitability, while during tDCS reverses effect to reduced excitability

Is coupling tDCS with training good?

1mV Pre-tDCS Post-tDCS Post-Robot

Anodal tDCS combined with robotic motor training

Group SICI Index

Conditioned / uncond MEP amplitude

0.5 1

p < 0.05

* *

Pre tDCS Post tDCS Post Robot

Edwards et al (2009)

Anodal tDCS combined with robotic motor training

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“Kinematic Robot-Based Evaluation Scales and Clinical Counterparts to Measure Upper Limb Motor Performance in Patients With Chronic Stroke” (Bosecker et al, 2009)

!"#"$%&'"()*(+,&"-%.,'(-"%/01"/(.)('#,&,'%#(*0&'.,)& Highest correlation with clinical function

P L E A S E D O N O T C O P Y

neutral extension

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• 16
• 7

2 11 20

Normalised data (%)

Key Findings: Effect of Intervention on Motor Performance

Giacobbe et al., (2013) C/-$"DB//5 D'++,H$/77 ;0' C/-$"DB//5

Training Alone Training + tDCS (pre) Training + tDCS (during) Training + tDCS post

Significant improvement Significant decrement 1203004 1203005 1203056 120307/

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Group Data n=12

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Timing of tDCS and behavioral therapy !"#$%&'(')*+,,',,-'./0*1232/*45,*678*

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Lo et al, NEJM (2010)

Usual care

* 36 session protocol chronic stroke

FM (max 66) Group SICI Index

Conditioned / uncond MEP amplitude

0.5 1

p < 0.05

* *

Pre tDCS Post tDCS Post Robot

Edwards et al (2009) Giacobbe et al (2013)

• 82 patients, right hemiparesis
• >6 mnths post first ischemic stroke
• Robotic protocol alternates S/E-wrist robot across sessions
• tDCS 2mA, 35cm2, 0.9% NaCl soaked sponges

Training Period 3x / wk, 12 weeks, 36 sessions 1 hour shoulder/elbow/wrist robotic training tDCS or sham pre training (2 groups) EVAL. EVAL. EVAL.

Combined tDCS-Robotic Training Study Design

EVAL. 1 wk 6 months EVAL. 1 wk

H1: Robot+tDCS > Robot+SHAMtDCS

• n UEFM improvement

P L E A S E D O N O T C O P Y

*Edwards et al. Accepted

+ Northstar Trial

Infarct

Pars triangularis

! Parameters:

• 2 runs of 20 minutes of cathodal

stimulation

• Electrode placement
• Cathode – R pars triangularis
• Anode – L supraorbital region
• Real – direct current of 2 mA
• Sham – direct current of 0.1 mA
• Worn during speech therapy

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P L E A S E D O N O T C O P Y

A. B. C.

4x HD Return Electrodes 1x HD Anode

400V TES 1000V TES 480V TES 600V TES 600V TES 600V TES

A2. C3. B (ii). C2. B (i).

Electric field/Current density

200µV 20ms

1000V TES

C3 Peak = 144 V/m C3 Peak = 216 V/m C3 Peak = 192 V/m C3 Peak = 240 V/m C3 Peak = 163 V/m C3 Peak = 96 V/m

C (i). C (ii). A (i). A (ii).

CS CS CS CS CS CS

20ms 100µV

C3 Peak = 5 V/m

C3

Primary Motor Cortex

F3 P3

anterior posterior

FC3 CP3

C3 Peak = 163 V/m C3 Peak = 80 V/m C3 Peak = 53 V/m C3 Peak = 8 V/m

CS CS CS CS CS

Physical presence of DC field in human tissue with tDCS

(magnitude v time)

Courtesy StarLab

• nset

time intensity

• nset

time MEP amplitude

Net Biological response to DC field in human tissue with tDCS (MEP amplitude v time)

Note: Theoretical

Lasting effect

P L E A S E D O N O T C O P Y

• nset

time intensity Reverse effects Opposing homeostatic forces Opposing homeostatic forces

Webster et al (2006)

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* Gerber et al, 2019

P L E A S E D O N O T C O P Y

Thank you

P L E A S E D O N O T C O P Y