Brain plasticity after implanted drop foot stimulator in chronic stroke

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Aurore THIBAUT, PhD

Coma Science Group, GIGA Research, Cyclotron Research Centre &

Neurology Department

University & University Hospital of Liège EAN, Berlin, June 20th_{, 2015}

Brain plasticity after

implanted drop foot

stimulator in chronic

stroke

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implantée chez le patient hémiplégique

External control unit

Microcontroller & transmitter

4-channels nerve stimulator Peroneal nerve

Drop foot stimulator

Receptor

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Methods

• Chronic stroke patients with drop foot • Rehazenter Lux (clinical tests) & ULg Be

(neuroimaging - EEG – PET – MRI)

• 21 patients included, 7 drop-out (stimulator issue) • 14 completed the study (5 wo, age: 47±12y, time

since insult: 2±1y, 7 lesion on the left) Clinical

tests Surgery EEG-PET-MRI Activation Clinical tests Clinical tests

Clinical tests EEG-PET-MRI Clinical tests -3 -2 -1 0 3 6 12 24 months

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Clinical improvement

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PET-scan: Analyses

18_{FGD-PET-scan at rest}

Pre-post : n=14 – right stroke: n=7; left stroke: n=7 7 patients with right lesion were flipped

all patients: lesion on the left hemisphere

Normalization with « flipped template » Smoothing at 12 mm

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Results: single subject

Lesion on the left

hypo before stim improvement DA

CS

SC

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Results: single subject

Lesion on the right

BD

JR

SV

0.05 uncorr

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Results: group

Hypometabolic areas

before activation 1 year later

0.05 FWE

Motor & premotor

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Results: group

Increase - motor areas left&right - Left prefrontal No decrease Recovery uncorr 0.01 Recovery uncorr 0.001

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Results: group

0 20 40 60 80 100 120 healthy side 0 20 40 60 80 100 120 damaged side

before 1year later

Brain metabolism in premotor cortex (B6)

before 1year later

% of normal br ai n me ta bol ism

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Analyses

• Power spectrum (delta, theta, alpha beta)

• Entropy

• Phase lag index  Motor area

• High density (256 electrodes) • Resting state for 30 min, EO

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Results: single subject

(right stroke)

Motor cortex delta alpha 1st_{exam 2}nd_{exam difference}

bet a al pha t he ta del ta

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Results: group

n=9 Motor area Data flipped Left lesion 1st_{exam 2}nd_{exam 1}st ≠ ₂nd

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Conclusion

Clinical improvements correlates

• brain metabolism (PET-scan) in motor areas (damaged & contralateral hemisphere)

• cortical activity (EEG) in motor area (damaged hemisphere)

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