Introduction: Verbal echoes are commonplace in patients with aphasia, yet information on their cognitive and
neural mechanisms remains unexplored (Berthier et al., in press). This study aims to instantiate the concept of
echolalia (Berthier et al., 2016) by reappraising its relevance in the frame of modern neuroscience in three
different types: (1) automatic echolalia (AE) (parrot-like repetition of all verbal stimuli); (2) mitigated echolalia
(ME) (changes in echoes for communicative purposes), and (3) effortful echolalia (EE) (echolalia with
articulatory struggling, distorted prosody, and increased effort).
Methods: Case-series study of three variants of echolalia in three patients with chronic post-stroke aphasia
using cognitive testing and multimodal imaging including structural magnetic resonance imaging (MRI),
diffusion tensor imaging (DTI), functional MRI (fMRI) during repetition of words and non-words, and resting
state fMRI (rsfMRI). Patient 1 had mixed transcortical aphasia (mutism and nil auditory comprehension with
intact repetition). Patient 2 had residual Wernicke’s aphasia with mildly impaired auditory comprehension; and
patient 3 had Broca’s aphasia with impaired syntactic comprehension.
Results: Patient 1 had severe AE associated with two large lesions in the left dorsolateral and mesial frontal
lobe and the left temporo-parietal cortex (isolation of speech area). DTI revealed absent left dorsal and ventral
streams and full development of right white matter tracts. Using fMRI and rsfMRI a compensatory activity in both
cerebral hemispheres (right greater than left) was found. Patient 2 had ME associated with DTI-proven
incomplete damage to the left dorsal stream and complete damaged to the left ventral stream. fMRI and rsfMRI
revealed compensatory activity via right hemisphere structures. Patient 3 had EE associated to a large lesion in
the left perisylvian language core.
Discussion:Our study revealed heterogeneous aphasic profiles and cognitive deficits in the different types of
echolalia amongst patients with chronic aphasia. In addition, multimodal imaging showed a complex pattern of
network rearrangement in both cerebral hemispheres which depended upon the localization of the structural
lesion. Our preliminary findings set out a starting point to advance research on echolalia eventually providing
hints for neurorehabilitation.
References: Berthier ML et al.. P. Coppens and J. Patterson (Eds.). Jones & Bartlett Learning, Burlington, MA
(2016)
Berthier ML et al. Aphasiology (2017)
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