Table 2.

Overview of functional imaging group studies (N>5 patients)

Study	Aims	Patient characteristics	Imaging techniques & paradigms	Main results	Conclusions
Meinzer et al., 2004	Localization of excessive slow wave activity in the delta frequency range and impact of changed activity after treatment	28 chronic patients treated with CI-based aphasia therapy or model-oriented therapy Time since stroke: 13–156 months	MEG, resting state Correlation of activity change with improvement (standardized language test, AAT Token Test and profile score) after therapy	Excessive slow wave activity was found mainly in perilesional areas Change in slow wave activity after treatment is correlated with the degree of improvement	Highlights the importance of perilesional brain areas in language rehabilitation Up- or down regulation of slow wave activity was associated with improvement, pointing to two different mechanisms of brain plasticity
Pulvermüller et al., 2005	Processing of language stimuli before and after intervention	9 patients with chronic aphasia Time since stroke: 16–233 months	EEG, word and pseudoword evoked electrocortical responses	Early word-evoked response changed after treatment, no change for pseudowords Correlation of treatment gains and brain activity changes in both hemispheres	Highlights the importance of right and left hemisphere for treatment success
Meinzer et al., 2008	Pre-post assessment of functional activity changes in individually determined ROIs based on areas of excessive slow wave activity	11 patients with chronic aphasia and anomia Time since stroke: 19–66 months	fMRI, overt picture naming task Correlation of activity changes with naming improvement	Positive correlation between increased activity in pre-defined slow wave ROIs and naming improvement No correlations in left and right hemisphere control ROIs	Study emphasizes importance of perilesional areas for language rehabilitation in the chronic stage of aphasia
Richter et al., 2008	Impact of right-hemisphere activity on “aphasia recovery potential” Pre-post assessments of activity changes in right hemisphere ROIs in response to treatment	16 patients with chronic aphasia Time since stroke: All >1 year	fMRI, reading and wordstem completion tasks Correlation of activity prior to treatment and activity changes after treatment with composite language score	More pronounced activity in right hemisphere ROIs prior to treatment predicted treatment outcome Decreased activity in right hemisphere ROIs after treatment was associated with improvement	Downregulation of “dysfunctional” right hemisphere activity may be associated with treatment-induced improvement
Breier et al., 2009	To assess specific brain activity changes associated with short- and long-term training success	23 patients with chronic aphasia Time since stroke: all >1 year	MEG, word recognition task Three assessment points (prior to and after treatment; 3-months follow-up) Patients were divided in three groups: (1) treatment responders who maintained gains (2) responders who lost gains at follow-up assessment (3) non-responders	Only group that maintained initial treatment gains showed consistent up-regulation of activity in left hemisphere at both assessments	Highlights the importance of perilesional areas in the left-hemisphere Groups with different treatment outcome show specific changes in brain activity Emphasizes the need for follow-up assessments as activity patterns show dynamic changes depending on treatment success

fMRI=functional magnetic resonance imaging; EEG=electroencephalography; MEG=magnetoencephalography; ROI=region-of-interest