Aphasia Neuroplasticity Review

Sims et al. (2016)

Reference

AuthorsSims JA, Kapse K, Glynn P, Sandberg C, Tripodis Y, Kiran S
TitleThe relationships between the amount of spared tissue, percent signal change, and accuracy in semantic processing in aphasia
ReferenceNeuropsychologia 2016; 84: 113-126
PMID26775192
DOI10.1016/j.neuropsychologia.2015.10.019

Participants

LanguageUS English
Inclusion criteriaSome spared tissue in L IFG
Number of individuals with aphasia14 (plus 2 excluded: 1 had no spared tissue in the L IFG; 1 had a R hemisphere stroke)
Number of control participants8
Were any of the participants included in any previous studies?Yes (although not stated, it is apparent that many of the patients were included in Sandberg et al. (2015))
Is age reported for patients and controls, and matched?Yes (mean 59.7 years, range 48-75 years)
Is sex reported for patients and controls, and matched?Yes (males: 10; females: 4)
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 6 years, range 6 months-13 years)
To what extent is the nature of aphasia characterized?Severity and type
Language evaluationWAB, BNT, PPT, CLQT
Aphasia severityAQ range 48.0-99.2
Aphasia type4 anomic, 2 Broca's, 2 conduction, 2 transcortical motor, 1 anomic or transcortical motor, 1 Broca's or conduction, 1 "N/A", 1 Wernicke's or conduction
First stroke only?Not stated
Stroke typeNot stated
To what extent is the lesion distribution characterized?Lesion overlay
Lesion extentNot stated
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 (Philips Achieva 3 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?No (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 notesno smoothing

Conditions

Are the conditions clearly described?No (number of visual decision trials not reported)
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
semantic feature decisionButton press64YesUnknown
visual decisionButton pressnot statedYesUnknown
semantic relatedness decisionButton press50YesUnknown
pseudoword identity decisionButton press50YesUnknown
restNoneimplicit baselineN/AN/A
Conditions notes

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: semantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision

Language conditionSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls)
Control conditionVisual decision or pseudoword identity decision
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, different
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?No
Does the contrast selectively activate plausible relevant language regions in the control group?Unknown
Are activations lateralized in the control data?Unknown
Control activation notes
Contrast notes8 patients and 4 controls performed one paradigm, while 6 patients and 4 controls performed another; the data were combined based on the assumption that similar processes were implicated by the two contrasts

Analyses

Are the analyses clearly described?No* (moderate limitation) (see specific limitation(s) below)

ROI analysis 1

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateSemantic feature decision accuracy
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?Accuracy is covariate
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeAnatomical
How many ROIs are there?16
What are the ROI(s)?(1) L IFG pars orbitalis; (2) L IFG pars opercularis; (3) L IFG pars triangularis; (4) L SFG; (5) L MFG; (6) L MTG; (7) L AG/SMG; (8) L ACC; (9-16) homotopic counterparts
How are the ROI(s) defined?AAL
Correction for multiple comparisonsNo correction
Statistical details
Findings↑ L IFG pars opercularis
↑ L IFG pars triangularis
Findings notes

ROI analysis 2

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateWAB AQ
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 analysisRegions of interest (ROI)
ROI typeAnatomical
How many ROIs are there?16
What are the ROI(s)?(1) L IFG pars orbitalis; (2) L IFG pars opercularis; (3) L IFG pars triangularis; (4) L SFG; (5) L MFG; (6) L MTG; (7) L AG/SMG; (8) L ACC; (9-16) homotopic counterparts
How are the ROI(s) defined?AAL
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notes

ROI analysis 3

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateBNT
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 analysisRegions of interest (ROI)
ROI typeAnatomical
How many ROIs are there?16
What are the ROI(s)?(1) L IFG pars orbitalis; (2) L IFG pars opercularis; (3) L IFG pars triangularis; (4) L SFG; (5) L MFG; (6) L MTG; (7) L AG/SMG; (8) L ACC; (9-16) homotopic counterparts
How are the ROI(s) defined?AAL
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notes

ROI analysis 4

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariatePPT
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 analysisRegions of interest (ROI)
ROI typeAnatomical
How many ROIs are there?16
What are the ROI(s)?(1) L IFG pars orbitalis; (2) L IFG pars opercularis; (3) L IFG pars triangularis; (4) L SFG; (5) L MFG; (6) L MTG; (7) L AG/SMG; (8) L ACC; (9-16) homotopic counterparts
How are the ROI(s) defined?AAL
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notes

ROI analysis 5

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion volume
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, matched
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesNo correlation between lesion volume and accuracy, not clear whether control condition accuracy was also tested
Type of analysisRegions of interest (ROI)
ROI typeAnatomical
How many ROIs are there?8
What are the ROI(s)?As above but only in the R hemisphere
How are the ROI(s) defined?AAL
Correction for multiple comparisonsNo correction
Statistical details
Findings↑ R supramarginal gyrus
↑ R angular gyrus
↑ R posterior MTG
Findings notesMTG included anterior too; SMG/AG was single ROI

Complex analysis 1

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion status of 8 ROIs
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 detailsMultivariate mixed-effects linear regression analyses were used to identify relationships between structural damage to 8 regions, and functional activation in 16 regions. Results were corrected for multiple comparisons based on FDR. This analysis was not described in sufficient detail.
FindingsOther
Findings notesSparing of the L ACC and L SFG was associated with more functional activation in many regions, however this is difficult to interpret since these regions were largely or completely spared in many patients. Damage to the L IFG pars orbitalis, L MTG and L AG/SMG was associated with activation of the L ACC, L SFG (and other regions) potentially indicative of compensatory processing.

Complex analysis 2

First level contrastSemantic feature decision (6 patients, 4 controls) or semantic relatedness decision (8 patients, 4 controls) vs visual decision or pseudoword identity decision
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?Unknown, not reported
Behavioral data notes
Type of analysisComplex
Statistical detailsCorrelations were computed between functional activation in 16 regions, and qualitatively compared between patients and controls (p. 123). There was no correction for multiple comparisons.
FindingsOther
Findings notesIn controls, all regions were generally correlated with one another. This was largely true in patients too, with the exception of the R IFG pars orbitalis, which was negatively correlated with the L IFG.

Notes

Excluded analysesPCA analysis (section 3.4.1)