Neuroimaging Correlates of Post-Stroke Aphasia Rehabilitation in a Pilot Randomized Trial of Constraint-Induced Aphasia Therapy

Abstract

BackgroundRecovery from post-stroke aphasia is a long and complex process with an uncertain outcome. Various interventions have been proposed to augment the recovery, including constraint-induced aphasia therapy (CIAT). CIAT has been applied to patients suffering from post-stroke aphasia in several unblinded studies to show mild-to-moderate linguistic gains. The aim of the present study was to evaluate the neuroimaging correlates of CIAT in patients with chronic aphasia related to left middle cerebral artery stroke.Material/MethodsOut of 24 patients recruited in a pilot randomized blinded trial of CIAT, 19 patients received fMRI of language. Eleven of them received CIAT (trained) and eight served as a control group (untrained). Each patient participated in three fMRI sessions (before training, after training, and 3 months later) that included semantic decision and verb generation fMRI tasks, and a battery of language tests. Matching healthy control participants were also included (N=38; matching based on age, handedness, and sex).ResultsLanguage testing showed significantly improved performance on Boston Naming Test (BNT; p<0.001) in both stroke groups over time and fMRI showed differences in the distribution of the areas involved in language production between groups that were not present at baseline. Further, regression analysis with BNT indicated changes in brain regions correlated with behavioral performance (temporal gyrus, postcentral gyrus, precentral gyrus, thalamus, left middle and superior frontal gyri).ConclusionsOverall, our results suggest the possibility of language-related cortical plasticity following stroke-induced aphasia with no specific effect from CIAT training.

Functional Magnetic Resonance Imaging of Language Following Constraint-Induced Aphasia Therapy Primed with Intermittent Theta Burst Stimulation in 13 Patients with Post-Stroke Aphasia

“…The lack of comparison groups also does not allow us to differentiate whether iTBS alone or CIAT alone would induce similar gains. A previous randomized controlled trial of CIAT for post-stroke aphasia did show improved naming performance over time and no change in perceived communicative ability [ 58 ], suggesting that effects we observed on naming ability may not be specific to CIAT primed with iTBS. However, the observed improvements in other measures have yet to be investigated in a randomized controlled trial.…”

Constrained-Induced Dysarthria Therapy: Case Report

“…Mechanisms underlying improvement by CIT are poorly understood. Enhanced cortical neuroplasticity, documented by transcranial magnetic stimulation and fMRI in subacute and chronic phase, may be associated with learned nonuse and the ability for compensation, rather than neurological repair or recovery [ 3 , 9 ]. As regards the acute phase, improvement is more clearly characterized by increased levels of neuroplasticity [ 3 ].…”

“…As regards the acute phase, improvement is more clearly characterized by increased levels of neuroplasticity [ 3 ]. This is the case for CIMT, whereas CIAT seems not to be associated with significant changes in cortical activity [ 9 ].…”

Constraint-induced aphasia therapy for patients with aphasia: A systematic review

“…Studies showed that high-intensity speech training can stimulate the corresponding brain language regions of patients and thus enable them to be gradually accustomed to normal language communication [ 17 , 18 ]. Neuroimaging-related studies exploring the change of brain areas concerning language and speech function after the training of CIAT showed that the activated areas primarily included the left hemisphere, such as left inferior frontal gyrus [ 19 ] and left middle frontal gyrus [ 20 ], which are considered language performance control regions.…”