transcranial Direct Current Stimulation & aphasia

(TEA):

a neuroimaging study

Marieke Blom-Smink

Kerstin Spielmann (RoNeRes)

Dr. Carolina Mendez Orellana (Pontificia Universidad Católica de Chile, Santiago)

Prof. Dr. Gerard Ribbers (RoNeRes)

Dr. Marion Smits (Erasmus MC)

Dr. Jenny Crinion (Institute of Cognitive Neuroscience, Londen)

Dr. Mieke van de Sandt-Koenderman (RoNeRes)

R o t t e r d a m N e u r o r e h a b i l i t a t i o n R e s e a r c h

RoNeRes

Overview

� tDCS and aphasia recovery

� tDCS and aphasia recovery > neural mechanisms

� TEA-imaging study

� aim

� protocol

� outcome measures

� analyses

� current status

� conclusions

transcranial Direct Current Stimulation

� www.neuroconn.de

� - non-invasive brain stimulation

� - weak electric current (1-2 mA)

� - anode > facilitates cell firing

Nitsche & Paulus, J Physiol (2000)

aphasia recovery

Saur et al., Brain 2006

tDCS and aphasia recovery

Schlaug et al., Arch Neurol 2008

tDCS and aphasia: neural mechanisms

� Ulm et al. (2015):

� A-tDCS over Broca’s area

> increased activity in Broca’s area during A-tDCS as compared

to sham-tDCS (n = 1; chronic stage)

� Meinzer et al. (2016):

� A-tDCS over primary motor cortex in left hemisphere

> reduced activity in domain-general regions

> increased language network activity as compared to sham-

tDCS (n = 16; chronic stage)

Aim of TEA-imaging study

� What is the effect of anodal tDCS, targeting Broca’s area, on the neural

reorganization of language in stroke patients with subacute aphasia,

specifically in the context of word finding therapy?

Spielmann et al., Trials 2016 http://news.mit.edu

Design of TEA study (n = 58)

(functional) Magnetic Resonance Imaging

Structural MRI:

� brain anatomy

� brain lesions

Functional MRI:

� brain activity

� increase in oxygen-rich blood

flow to active brain areas

� change in blood oxygenation is

imaged

(f)MRI protocol

� Before treatment:

� Structural MRI scan

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

Structural MRI scan

� L R

(f)MRI protocol

� Before treatment:

� Structural MRI scan

� Functional MRI scan:

� Auditory comprehension task

� After treatment:

� Functional MRI scan:

� Auditory comprehension task

fMRI scan – auditory comprehension

Before treatment: R L

After treatment: R L

(f)MRI protocol

� Before treatment:

� Structural MRI scan

� Functional MRI scan:

� Auditory comprehension task

� After treatment:

� Functional MRI scan:

� Auditory comprehension task

� Picture naming task

fMRI scan – picture naming

After treatment: R L

Outcome measures – TEA-imaging study

� Structural scan:

� lesion location

� lesion volume

� Functional scans:

� activated brain regions > auditory comprehension (pre / post

treatment)

> picture naming (post treatment)

� lateralization indices > auditory comprehension (pre / post

treatment)

> picture naming (post treatment)

Lateralization Index

� LI = (LH – RH) / (LH + RH)

� 0.1 < LI < 1.0 left hemispheric dominance

� -1.0 < LI < -0.1 right hemisphere dominance

� -0.1 < LI < 0.1 bilateral activation

Outcome measures – TEA-behavioral study

� Language measures

� Boston Naming Test

� Amsterdam-Nijmegen Everyday Language Test

� Aphasia Severity Rating Scale

Analyses – TEA-imaging study

� Lesion site and lesion size

� LI auditory comprehension pre / post: tDCS <> sham

� LI picture naming post: tDCS <> sham

� Activated brain regions auditory comprehension pre / post

� Activated brain regions picture naming post

� Language measures

Current status

� Participants: n = 13 (8 men, age 49-73)

� Lesions:

� site: under review by neuroradiologist

� size: M = 36.04 ml (range = 5.57 - 154.57)

� LIs: extracted last Monday ☺

Conclusions

� Results:

� will improve understanding of roles of LH and RH in neural

reorganization of language in aphasia in subacute stage after

stroke

� will contribute to the ongoing investigation of tDCS as adjunct

intervention to language therapy

Thank you for your attention