Aphasia Neuroplasticity Review

Pillay et al. (2018)

Reference

AuthorsPillay SB, Gross WL, Graves WW, Humphries C, Book DS, Binder JR
TitleThe neural basis of successful word reading in aphasia
ReferenceJ Cogn Neurosci 2018; 30: 514-525
PMID29211656
DOI10.1162/jocn_a_01214

Participants

LanguageUS English
Inclusion criteriaResidual phonologic retrieval deficit; intact semantic processing
Number of individuals with aphasia21
Number of control participants0
Were any of the participants included in any previous studies?No
Is age reported for patients and controls, and matched?Yes (mean 56.4 ± 12.5 years, range 30-80 years)
Is sex reported for patients and controls, and matched?Yes (males: 11; females: 10)
Is handedness reported for patients and controls, and matched?Yes (right: 21; left: 0)
Is time post stroke onset reported and appropriate to the study design?Yes (mean 1134 ± 1491 days, range 180-6732 days)
To what extent is the nature of aphasia characterized?Not at all
Language evaluationPseudoword rhyme matching, semantic picture matching (similar to PPT-P), picture naming
Aphasia severityNot stated
Aphasia typeNot stated
First stroke only?Not stated
Stroke typeIschemic only
To what extent is the lesion distribution characterized?Lesion overlay
Lesion extentMean 73.4 ± 58.6 cc, range 6.7-227.0 cc
Lesion location17 L MCA, 2 combined L MCA/ACA, combined 2 L MCA/PCA
Participants notes

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 (GE Excite 3 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?No (precise timing of stimuli not stated; total images acquired not stated)
Design typeEvent-related
Total images acquirednot stated
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 notes

Conditions

Are the conditions clearly described?Yes
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
reading nouns aloudWord (overt)72YesNo
restNoneimplicit baselineN/AN/A
Conditions notesSome participants had < 10% accuracy, but this is appropriately addressed in the analysis

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: reading nouns aloud (correct trials) vs reading nouns aloud (incorrect trials)

Language conditionReading nouns aloud (correct trials)
Control conditionReading nouns aloud (incorrect trials)
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?No, by design
Is reaction time matched between the language and control tasks for all relevant groups?Yes, matched
Behavioral data notes
Are control data reported in this paper or another that is referenced?N/A
Does the contrast selectively activate plausible relevant language regions in the control group?N/A
Are activations lateralized in the control data?N/A
Control activation notesControl data N/A because controls do not typically make errors
Contrast notes

Analyses

Are the analyses clearly described?Yes

Voxelwise analysis 1

First level contrastReading nouns aloud (correct trials) vs reading nouns aloud (incorrect trials)
Analysis classCross-sectional performance-defined conditions
Group(s)Aphasia
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?No, by design
Is reaction time matched across the second level contrast?Yes, matched
Behavioral data notes
Type of analysisVoxelwise
Search volumeWhole brain
Correction for multiple comparisonsClusterwise correction based on 3dClustSim
SoftwareAFNI
Voxelwise p.01
Cluster extent1.609 cc
Statistical detailsRegarding correction for multiple comparisons, addition of monoexponential function reduces but does not eliminate inflation of p values (Cox et al., 2017)
Findings↑ L angular gyrus
↓ L ventral precentral/inferior frontal junction
↓ L SMA/medial prefrontal
↓ R insula
↓ R ventral precentral/inferior frontal junction
↓ R SMA/medial prefrontal
Findings notesPositive region (L AG) was part of the semantic network, while many negative regions were positively modulated by reaction time in the aphasia group

Notes

Excluded analyses(1) ancillary analysis in which similar findings were obtained when phonological impairment was included as a covariate; (2) ancillary analysis in which similar findings were obtained when lesioned patients were excluded at each voxel; (3) analysis of modulation by reaction time (while informative, this analysis does not meet our inclusion criteria)