Aphasia Neuroplasticity Review

Skipper-Kallal et al. (2017b)

Reference

AuthorsSkipper-Kallal LM, Lacey EH, Xing S, Turkeltaub PE
TitleFunctional activation independently contributes to naming ability and relates to lesion site in post-stroke aphasia
ReferenceHum Brain Mapp 2017b; 38: 2051-2066
PMID28083891
DOI10.1002/hbm.23504

Participants

LanguageUS English
Inclusion criteriaAble to name 20% of pictures correctly in the scanner
Number of individuals with aphasia32 (plus 14 excluded: < 20% accuracy in scanner)
Number of control participants25
Were any of the participants included in any previous studies?Yes (29 of the participants overlap with the other Skipper-Kallal et al. (2017) paper)
Is age reported for patients and controls, and matched?Yes (mean 58.8 ± 8.6 years, range 45.7-78.2 years)
Is sex reported for patients and controls, and matched?Yes (males: 19; females: 12; stated to be not matched, but difference not significant)
Is handedness reported for patients and controls, and matched?Yes (right: 26; left: 3; other: 2)
Is time post stroke onset reported and appropriate to the study design?Yes (mean 40.9 ± 36.1 months, 4.9-151.0 months)
To what extent is the nature of aphasia characterized?Comprehensive battery
Language evaluationWAB, PNT
Aphasia severityAQ mean 77.7 ± 21.0, range 22.8-99.2
Aphasia type21 anomic, 7 Broca's, 3 conduction, 1 transcortical sensory
First stroke only?Not stated
Stroke typeNot stated
To what extent is the lesion distribution characterized?Lesion overlay
Lesion extentMean 27.5 ± 22.9 cc
Lesion locationL MCA
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 (Siemens Trio 3 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?No* (moderate limitation) (total images acquired not stated; separation of adjacent events (covert and overt naming) will be limited because of the small amount of jitter in their timing (only 1500 ms))
Design typeEvent-related
Total images acquired~450 but not 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?No* (moderate limitation) (entire phases where picture was displayed modeled as covert and overt naming; difficult to separate phases due to timing)
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?
picture naming (silently name)Word (covert)32YesYes
picture naming (produce the name)Word (overt)32YesYes
restNoneimplicit baselineN/AN/A
Conditions notesCovert and overt naming were modeled as two phases of each trial (there was a cue to produce the name after 7500-9000 ms); 5 participants who were more impaired were given easier pictures to name; patients who named less than 20% of items correctly were excluded

Contrasts

Are the contrasts clearly described?No (see specific limitation(s) below)

Contrast 1: picture naming (silently name, correct trials) vs rest

Language conditionPicture naming (silently name, correct trials)
Control conditionRest
Are the conditions matched for visual demands?No
Are the conditions matched for auditory demands?Yes
Are the conditions matched for motor demands?Yes
Are the conditions matched for cognitive/executive demands?No
Is accuracy matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Is reaction time matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Behavioral data notes
Are control data reported in this paper or another that is referenced?Yes
Does the contrast selectively activate plausible relevant language regions in the control group?No
Are activations lateralized in the control data?No
Control activation notesBilateral frontal and occipito-temporal, but not posterior temporal
Contrast notes

Contrast 2: picture naming (produce the name, correct trials) vs rest

Language conditionPicture naming (produce the name, correct trials)
Control conditionRest
Are the conditions matched for visual demands?No
Are the conditions matched for auditory demands?No
Are the conditions matched for motor demands?No
Are the conditions matched for cognitive/executive demands?No
Is accuracy matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Is reaction time matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Behavioral data notes
Are control data reported in this paper or another that is referenced?Yes
Does the contrast selectively activate plausible relevant language regions in the control group?No
Are activations lateralized in the control data?No
Control activation notesBilateral frontal and occipito-temporal, but not posterior temporal; speech motor activation not readily apparent
Contrast notes

Contrast 3: picture naming (both phases, correct trials) vs picture naming (both phases, incorrect trials)

Language conditionPicture naming (both phases, correct trials)
Control conditionPicture naming (both phases, incorrect trials)
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?Unknown
Are the conditions matched for motor demands?Unknown
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?Unknown, not reported
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 notesIt is unclear whether there were no-response trials and whether they were modeled as incorrect

Analyses

Are the analyses clearly described?Yes

Voxelwise analysis 1

First level contrastPicture naming (silently name, correct trials) vs rest
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesCovert phase but accuracy derived from overt phase
Type of analysisVoxelwise
Search volumeWhole brain gray matter
Correction for multiple comparisonsClusterwise correction with with GRFT and lenient voxelwise p
SoftwareFSL 5.0.6
Voxelwise p~.01 (z > 2.3)
Cluster extentBased on GRFT
Statistical detailsThreshold of z > 3.1 mentioned in results, but presume 2.3 based on methods and figure
Findings↑ R precuneus
↓ L occipital
Findings notes

Voxelwise analysis 2

First level contrastPicture naming (produce the name, correct trials) vs rest
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisVoxelwise
Search volumeWhole brain gray matter
Correction for multiple comparisonsClusterwise correction with with GRFT and lenient voxelwise p
SoftwareFSL 5.0.6
Voxelwise p~.01 (z > 2.3)
Cluster extentBased on GRFT
Statistical detailsThreshold of z > 3.1 mentioned in results, but presume 2.3 based on methods and figure
Findings↑ L SMA/medial prefrontal
↑ L orbitofrontal
↑ L precuneus
↑ R insula
↑ R ventral precentral/inferior frontal junction
↑ R SMA/medial prefrontal
↑ R orbitofrontal
↑ R somato-motor
↑ R supramarginal gyrus
↑ R posterior STS
↓ L IFG
↓ L insula
↓ L ventral precentral/inferior frontal junction
↓ L intraparietal sulcus
↓ L anterior temporal
↓ L hippocampus/MTL
↓ R intraparietal sulcus
Findings notesLabels based largely on text with some adjustments based on figures; overall pattern of decreased L activity and increased R activity is quite convincing

Voxelwise analysis 3

First level contrastPicture naming (silently name, correct trials) vs rest
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariatePNT
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesCovert phase but accuracy derived from overt phase
Type of analysisVoxelwise
Search volumeWhole brain gray matter
Correction for multiple comparisonsClusterwise correction with with GRFT and lenient voxelwise p
SoftwareFSL 5.0.6
Voxelwise p~.01 (z > 2.3)
Cluster extentBased on GRFT
Statistical details
Findings↑ L anterior temporal
↓ L SMA/medial prefrontal
↓ L supramarginal gyrus
↓ R SMA/medial prefrontal
↓ R somato-motor
Findings notesL anterior temporal correlation remained significant after accounting for lesion load and other factors

Voxelwise analysis 4

First level contrastPicture naming (produce the name, correct trials) vs rest
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariatePNT
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisVoxelwise
Search volumeWhole brain gray matter
Correction for multiple comparisonsClusterwise correction with with GRFT and lenient voxelwise p
SoftwareFSL 5.0.6
Voxelwise p~.01 (z > 2.3)
Cluster extentBased on GRFT
Statistical details
Findings↑ L posterior STG
↑ R somato-motor
↑ R posterior STS
↑ R occipital
↓ L IFG pars orbitalis
↓ L dorsolateral prefrontal cortex
↓ L angular gyrus
Findings notesL IFG pars orbitalis, R pSTS, and R somato-motor correlations remained remained significant after accounting for lesion load and other factors; note that the pars orbitalis region is described as frontal pole in the paper but the coordinates and image support pars orbitalis

Voxelwise analysis 5

First level contrastPicture naming (both phases, correct trials) vs picture naming (both phases, incorrect trials)
Analysis classCross-sectional performance-defined conditions
Group(s)Aphasia with naming < 80% (n = 24)
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?Unknown, not reported
Behavioral data notes
Type of analysisVoxelwise
Search volumeWhole brain gray matter
Correction for multiple comparisonsClusterwise correction with with GRFT and lenient voxelwise p
SoftwareFSL 5.0.6
Voxelwise p~.01 (z > 2.3)
Cluster extentBased on GRFT
Statistical details
FindingsNone
Findings notes

ROI analysis 1

First level contrastPicture naming (produce the name, correct trials) vs rest
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariatePNT
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeFunctional
How many ROIs are there?11
What are the ROI(s)?(1) right IPS; (2) left IPS; (3) left PTr; (4) left dPOp; (5) right superior motor cortex; (6) right ventral motor cortex; (7) right supramarginal sulcus; (8) left medial SMA; (9) right marginal sulcus; (10) left dorsal motor cortex; (11) right STS
How are the ROI(s) defined?Regions that were activated for control > aphasia (ROIs 1-4) or aphasia > control (ROIs 5-11)
Correction for multiple comparisonsFamilywise error (FWE)
Statistical details
Findings↑ R ventral precentral/inferior frontal junction
↑ R posterior STS
↓ L IFG pars opercularis
Findings notesThe L IFG pars opercularis and the R posterior STS also contributed to predicting PNT scores even when lesion load on critical areas for picture naming, and several other variables, were included in multiple regression models

ROI analysis 2

First level contrastPicture naming (silently name, correct trials) vs rest
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?Yes, correct trials only
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 anterior temporal
How are the ROI(s) defined?Activity for covert naming correlated with naming ability in patients, after controlling for lesion and demographic factors
Correction for multiple comparisonsOne only
Statistical details
FindingsNone
Findings notes

ROI analysis 3

First level contrastPicture naming (produce the name, correct trials) vs rest
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeFunctional
How many ROIs are there?3
What are the ROI(s)?(1) L frontal pole; (2) R postcentral gyrus; (3) R STS
How are the ROI(s) defined?Activity for overt naming correlated with naming ability in patients, after controlling for lesion and demographic factors
Correction for multiple comparisonsNo correction
Statistical details
Findings↑ R somato-motor
↑ R posterior STS
Findings notes

Complex analysis 1

First level contrastPicture naming (produce the name, correct trials) vs rest
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion patterns identified with SVR-LSM
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisComplex
Statistical detailsSVR-LSM was used to identify regions of damage associated with activation of R pSTS ROI (defined based on SPM analysis 2). The results were thresholded at voxelwise p < .01 (CDT), cluster extent > 500 voxels.
FindingsOther
Findings notesDamage to the L IFG pars opercularis was associated with more activity in the R pSTS. Damage to the L pSTS was associated with less activity in the R pSTS.

Complex analysis 2

First level contrastPicture naming (produce the name, correct trials) vs rest
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia without IFG POp damage (n = 26)
CovariateLesion patterns identified with SVR-LSM
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?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisComplex
Statistical detailsSVR-LSM was used to identify regions of damage associated with activation of L IFG pars opercularis ROI (defined based on SPM analysis 2). The results were thresholded at voxelwise p < .01 (CDT), cluster extent > 500 voxels.
FindingsOther
Findings notesDamage to the L pSTG, L pSTS, and white matter underlying the L precuneus was associated with more activity in the L IFG pars opercularis. There were no regions associated with less activity.

Notes

Excluded analysesNegative correlation between functional activation in the L IFG pars opercularis and R pSTS