Aphasia Neuroplasticity Review

Abel et al. (2015)

Reference

Authors	Abel S, Weiller C, Huber W, Willmes K, Specht K
Title	Therapy-induced brain reorganization patterns in aphasia
Reference	Brain 2015; 138: 1097-1112
PMID	25688082
DOI	10.1093/brain/awv022

Participants

Language	German
Inclusion criteria	Anomia; no severe AoS or dysarthria
Number of individuals with aphasia	14 (plus 9 excluded: 4 for ceiling performance; 5 for technical problems)
Number of control participants	14
Were any of the participants included in any previous studies?	Yes (same dataset as Abel et al. (2014))
Is age reported for patients and controls, and matched?	Yes (median 48 years, range 35-74 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 (median 41 months, range 11-72 months)
To what extent is the nature of aphasia characterized?	Type only
Language evaluation	AAT
Aphasia severity	Not stated
Aphasia type	8 Broca's, 3 Wernicke's, 1 fluent non-classifiable, 1 global, 1 transcortical sensory
First stroke only?	Yes
Stroke type	Mixed etiologies
To what extent is the lesion distribution characterized?	Lesion overlay
Lesion extent	Not stated
Lesion location	L MCA; 2 also had ACA
Participants notes	—

Imaging

Modality	fMRI
Is the study cross-sectional or longitudinal?	Longitudinal—chronic treatment
If longitudinal, at what time point(s) were imaging data acquired?	T1: pre-treatment/chronic; T2: post-treatment, ~6 weeks later (labeled T2 and T3 in paper)
If longitudinal, was there any intervention between the time points?	Lexical therapy, alternating between weeks with phonological and semantic treatment, 4 weeks; 60 out of the 132 items were trained
Is the scanner described?	Yes (Philips Achieva 3 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?	No* (moderate limitation) (trials too close together (~8 s) and insufficient jitter (1-3 s) for event-related design)
Design type	Event-related
Total images acquired	560
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?	No (lesion impact not addressed)
Imaging notes	—

Conditions

Are the conditions clearly described?

Yes

Condition	Response type	Repetitions	All groups could do?	All individuals could do?
picture naming	Word (overt)	132	Yes	Yes
rest	None	implicit baseline	N/A	N/A

Conditions notes

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Contrasts

Are the contrasts clearly described?

Yes

Contrast 1: picture naming vs rest

Language condition	Picture naming
Control condition	Rest
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 notes	Bilateral somato-motor, auditory and to a lesser extent higher level visual regions; finite impulse analysis only
Contrast notes	—

Analyses

Are the analyses clearly described?

Yes

Voxelwise analysis 1

First level contrast	Picture naming vs rest
Analysis class	Longitudinal change in aphasia
Group(s)	Aphasia T2 vs T1
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, different
Is reaction time matched across the second level contrast?	No, different
Behavioral data notes	RT shorter at T2
Type of analysis	Voxelwise
Search volume	Whole brain
Correction for multiple comparisons	Clusterwise correction based on cluster_threshold_beta
Software	SPM8
Voxelwise p	.01
Cluster extent	11 voxels (size not stated)
Statistical details	—
Findings	↓ L IFG pars triangularis ↓ L dorsolateral prefrontal cortex ↓ L ventral precentral/inferior frontal junction ↓ L dorsal precentral ↓ L SMA/medial prefrontal ↓ L somato-motor ↓ L inferior parietal lobule ↓ L precuneus ↓ L posterior cingulate ↓ L cerebellum ↓ R SMA/medial prefrontal ↓ R somato-motor ↓ R precuneus ↓ R posterior STS ↓ R posterior MTG ↓ R posterior cingulate ↓ R cerebellum ↓ R thalamus ↓ R hippocampus/MTL
Findings notes	—

Voxelwise analysis 2

First level contrast	Picture naming vs rest
Analysis class	Cross-sectional aphasia vs control
Group(s)	Aphasia T1 vs control T1
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?	Appear mismatched
Is reaction time matched across the second level contrast?	No, different
Behavioral data notes	Controls responded more quickly
Type of analysis	Voxelwise
Search volume	Whole brain
Correction for multiple comparisons	Clusterwise correction based on cluster_threshold_beta
Software	SPM8
Voxelwise p	.01
Cluster extent	11 voxels (size not stated)
Statistical details	—
Findings	↑ R precuneus ↓ L somato-motor ↓ L Heschl's gyrus ↓ L anterior cingulate ↓ L posterior cingulate ↓ L thalamus ↓ L basal ganglia ↓ R insula ↓ R somato-motor ↓ R mid temporal
Findings notes	—

Voxelwise analysis 3

First level contrast	Picture naming vs rest
Analysis class	Longitudinal aphasia vs control
Group(s)	(Aphasia T2 vs T1) vs (control T2 vs T1)
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?	Appear mismatched
Is reaction time matched across the second level contrast?	Unknown, not reported
Behavioral data notes	RT not reported for controls
Type of analysis	Voxelwise
Search volume	Whole brain
Correction for multiple comparisons	Clusterwise correction based on cluster_threshold_beta
Software	SPM8
Voxelwise p	.01
Cluster extent	11 voxels (size not stated)
Statistical details	—
Findings	↓ L precuneus ↓ L anterior cingulate ↓ L posterior cingulate ↓ L basal ganglia ↓ R precuneus ↓ R posterior STS ↓ R posterior MTG ↓ R posterior cingulate ↓ R thalamus ↓ R hippocampus/MTL
Findings notes	—

Voxelwise analysis 4

First level contrast	Picture naming vs rest
Analysis class	Cross-sectional aphasia vs control
Group(s)	Aphasia T1 vs control T1
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?	Appear mismatched
Is reaction time matched across the second level contrast?	Unknown, not reported
Behavioral data notes	RT not reported for controls
Type of analysis	Voxelwise
Search volume	Whole brain
Correction for multiple comparisons	No direct comparison
Software	SPM8
Voxelwise p	—
Cluster extent	—
Statistical details	Qualitative comparison between activation in the first 5 TRs after each stimulus on p. 1101
Findings	None
Findings notes	The time course of response is stated to be similar in patients and controls, however the response in patients appears like it could be a couple of seconds slower

Complex analysis 1

First level contrast	Picture naming vs rest
Analysis class	Cross-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?	No, different
Is reaction time matched across the second level contrast?	Unknown, not reported
Behavioral data notes	RT not reported for controls
Type of analysis	Complex
Statistical details	Joint ICA was performed on structural and functional contrast images using FIT 1.2c. Three of the 7 components differed between groups in their loadings. Components were thresholded at z > 3.09, not corrected for multiple comparisons.
Findings	Other
Findings notes	Three structural-functional components are described in Figure 5 and Table 4. Functional activations are generally small and do not obviously relate to language processing. It is mentioned in the supplementary results that "the lesion maps may dominate estimation of the mixing parameter" (p. 10).

Notes

Excluded analyses

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