Aphasia Neuroplasticity Review

Tyler et al. (2010)

Reference

AuthorsTyler LK, Wright P, Randall B, Marslen-Wilson WD, Stamatakis EA
TitleReorganization of syntactic processing following left-hemisphere brain damage: does right-hemisphere activity preserve function?
ReferenceBrain 2010; 133: 3396-3408
PMID20870779
DOI10.1093/brain/awq262

Participants

LanguageUK English
Inclusion criteria
Number of individuals with aphasia14
Number of control participants10
Were any of the participants included in any previous studies?No
Is age reported for patients and controls, and matched?Yes (mean 54 years, range 33-76 years)
Is sex reported for patients and controls, and matched?Yes (males: 11; females: 3)
Is handedness reported for patients and controls, and matched?Yes (right: 14; left: 0)
Is time post stroke onset reported and appropriate to the study design?Yes (mean 7 years, range 1.4-37.3 years)
To what extent is the nature of aphasia characterized?Not at all
Language evaluationSentence-picture matching, lexical decision, phonological similarity, word repetition, sentence repetition, morphological similarity, semantic categorization, sentence acceptability
Aphasia severityNot stated
Aphasia typeNot stated
First stroke only?Not stated
Stroke typeMixed etiologies
To what extent is the lesion distribution characterized?Lesion overlay
Lesion extentNot stated
Lesion locationL
Participants notes2 of the 14 patients were not stroke, but were post resective surgery

Imaging

ModalityfMRI
Is the study cross-sectional or longitudinal?Cross-sectional
If longitudinal, at what time point(s) were imaging data acquired?
If longitudinal, was there any intervention between the time points?
Is the scanner described?Yes (Siemens Trio 3 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?No* (moderate limitation) (there was only one block per condition per run, so condition could be confounded with low frequency drift; also, the length of the sentences is not stated so it is unclear how well the HRF peak aligns with the sparse acquisitions)
Design typeBlock
Total images acquired69
Are the imaging acquisition parameters, including coverage, adequately described and appropriate?Yes (whole brain)
Is preprocessing and intrasubject coregistration adequately described and appropriate?Yes
Is first level model fitting adequately described and appropriate?Yes
Is intersubject normalization adequately described and appropriate?Yes
Imaging notessparse sampling

Conditions

Are the conditions clearly described?Yes
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
listening to normal sentences and detecting a target wordButton press2YesUnknown
listening to grammatical but meaningless sentences and detecting a target wordButton press2YesUnknown
listening to scrambled sentences and detecting a target wordButton press2YesUnknown
listening to "musical rain" and detecting a period of white noiseButton press2YesUnknown
restNone2N/AN/A
Conditions notesAuditory presentation; target detection task with early and late targets; 12-15 trials per block with single sparse acquisition each, but only one block per run, in fixed order; task can apparently be performed by patients with brain damage, but accuracy is not reported

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: listening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word

Language conditionListening to grammatical but meaningless sentences and detecting a target word
Control conditionListening to scrambled sentences and detecting a target word
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?Yes
Are the conditions matched for motor demands?Yes
Are the conditions matched for cognitive/executive demands?Yes
Is accuracy matched between the language and control tasks for all relevant groups?Unknown, not reported
Is reaction time matched between the language and control tasks for all relevant groups?Appear similar
Behavioral data notesThere appears to be a small RT difference (control condition slower)
Are control data reported in this paper or another that is referenced?Somewhat
Does the contrast selectively activate plausible relevant language regions in the control group?Yes
Are activations lateralized in the control data?No
Control activation notesThere are more control participants in another paper (Tyler et al., 2010, Cereb Cortex), but the relevant contrast does not seem to be shown in that paper
Contrast notesThe contrast is intended to identify regions involved in syntactic processing, however it seems possible that there are semantic differences between these conditions also

Analyses

Are the analyses clearly described?Yes

Voxelwise analysis 1

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional aphasia vs control
Group(s)Aphasia vs control
Covariate
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Appear similar
Behavioral data notesThe two groups showed similar differences between RTs in the two conditions of the contrast
Type of analysisVoxelwise
Search volumeWhole brain
Correction for multiple comparisonsNo direct comparison
SoftwareSPM5
Voxelwise p
Cluster extent
Statistical detailsQualitative comparison on pp. 3402-3; each group is presented at voxelwise p < .005 (CDT), cluster-corrected p < .05 with GRFT
Findings↑ R IFG pars triangularis
↑ R IFG pars orbitalis
↓ L posterior MTG
Findings notesSeveral other potential differences are apparent in the figure, but only the differences tabulated are interpreted in the text

ROI analysis 1

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateRT difference between early and late targets on grammatical but meaningless sentences (a measure of syntactic processing)
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesAnalyses focuses on RT differences between early and late targets, not on mean RT per se
Type of analysisRegion of interest (ROI)
ROI typeFunctional
How many ROIs are there?1
What are the ROI(s)?L IFG pars triangularis and orbitalis
How are the ROI(s) defined?Activated for the same contrast
Correction for multiple comparisonsOne only
Statistical details
Findings↑ L IFG pars triangularis
↑ L IFG pars orbitalis
Findings notesL IFG showed more activation in patients that had a larger target position effect (indicative of better syntactic processing)

ROI analysis 2

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateRT difference between early and late targets on normal sentences
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegion of interest (ROI)
ROI typeFunctional
How many ROIs are there?1
What are the ROI(s)?L IFG pars triangularis and orbitalis
How are the ROI(s) defined?Activated for the same contrast
Correction for multiple comparisonsOne only
Statistical details
FindingsNone
Findings notes

ROI analysis 3

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateRT difference between early and late targets on scrambled sentences
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegion of interest (ROI)
ROI typeFunctional
How many ROIs are there?1
What are the ROI(s)?L IFG pars triangularis and orbitalis
How are the ROI(s) defined?Activated for the same contrast
Correction for multiple comparisonsOne only
Statistical details
FindingsNone
Findings notes

ROI analysis 4

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateDamage to L IFG, estimated from T1 signal
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegion of interest (ROI)
ROI typeFunctional
How many ROIs are there?1
What are the ROI(s)?R IFG pars triangularis and orbitalis
How are the ROI(s) defined?Activated for the same contrast
Correction for multiple comparisonsOne only
Statistical details
FindingsNone
Findings notesNo correlation (p = .57)

ROI analysis 5

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateSyntactic processing (presumably the target position effect, though this is not stated)
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegion of interest (ROI)
ROI typeFunctional
How many ROIs are there?1
What are the ROI(s)?R IFG pars triangularis and orbitalis
How are the ROI(s) defined?Activated for the same contrast
Correction for multiple comparisonsOne only
Statistical details
FindingsNone
Findings notesNo correlation (p = .41)

Complex analysis 1

First level contrastListening to grammatical but meaningless sentences and detecting a target word vs listening to scrambled sentences and detecting a target word
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion status of each voxel
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisComplex
Statistical detailsVBM was used to identify any regions where damage was predictive of activation in the L IFG pars triangularis and orbitalis. Tissue integrity was quantified in terms of T1 signal. Clusterwise correction was used, which is not appropriate for VBM.
FindingsOther
Findings notesOnly in the L IFG itself was damage predictive of reduced activation in the L IFG.

Notes

Excluded analyses(1) patients, unlike controls, showed a correlation between R IFG and R MTG activity, but the authors do not make much of this, and there is no direct comparison was reported to controls; (2) a nonsignificant correlation between L pMTG activation in patients (lacking at the group level) and tissue integrity in that same region