Are you a doctor? … Are you a doctor? I’m not a doctor! A reappraisal of mitigated echolalia in aphasia with evaluation of neural correlates and treatment approaches

ABSTRACT

Background: Mitigated echolalia (ME) is a symptom of aphasia which refers to a seemingly deliberate repetition of just-heard words and phrase fragments. ME has historically been viewed as a compensatory strategy aimed to strengthen auditory comprehension. Nevertheless, this hypothesis and other possible functional deficits underlying ME have not been evaluated so far.

Aims: This study aimed to (a) reappraise ME in the frame of modern neuroscience; (b) report the effects of Constraint-Induced Aphasia Therapy (CIAT) and a cognition-enhancing drug (memantine) on detrimental ME in a patient (CCR) with fluent aphasia; and (c) analyse the functional and structural brain correlates of ME in CCR with multimodal neuroimaging.

Methods & Procedure: Tasks tapping verbal expression and auditory comprehension were administered to CCR to evaluate ME. After baseline testing, evaluations were performed under placebo alone (weeks 0–16), combined placebo with CIAT (weeks 16–18), placebo treatment alone (weeks 18–20), washout (weeks 20–24) and memantine (weeks 24–48). Instructions to reduce ME during CIAT were provided to CCR. Language evaluation and multimodal neuroimaging were also performed 10 years after ending treatment.

Outcomes & Results: At baseline, ME occurred in spontaneous speech and in difficult-to-understand single words, indicating impaired meaning access. However, more instances of ME were heard in sentence comprehension, reflecting additional impairment in short-term memory. ME also occurred in words that were correctly defined and understood to the extent that even after accessing word meaning successfully, CCR repeated the same word several times, suggesting impaired inhibitory response control. In comparison with baseline, analysis of auditory sentence comprehension under treatment revealed significant decrements of ME just after ending CIAT and 2 weeks later. These gains were maintained under memantine 6 months later. No changes in ME were found during both placebo and washout phases. Instructions to constrain ME reduced the time to complete a sentence comprehension task 2 weeks after CIAT. ME returned to baseline levels 10 years later. Multimodal imaging suggested that ME in CCR resulted from residual activity of remnants of the left dorsal stream and the intact right white matter tracts after extensive damage to the left ventral stream.

Conclusions: ME in CCR interfered with functional communication, and it may be attributed to deficits in sound-meaning mapping, auditory short-term memory, attentional control, and inhibition of repetition mechanisms. Our preliminary evidence suggests that ME, in patients like CCR, may be modulated with specific instructions during aphasia therapy and drugs.

KEYWORDS:

• Aphasia
• mitigated echolalia
• neuroimaging
• constraint-induced aphasia therapy
• memantine

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental meterial

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Notes

1. The term echophenomena, also known as imitation behaviour (De Renzi, Cavalleri, & Facchini, 1996) or resonance behaviour (Rizzolatti, Fadiga, Fogassi, & Gallese, 1999), refers to an act of social dependence (person-based activation) characterised by a tendency to imitate the gestures and utterances that the examiner makes in front of the patient even when no specific instruction has been given to do so (Berthier, 1999; Ford, 1989; Stengel, 1947).

2. Word-meaning deafness is an exceptional disorder in which the patient “can repeat the words he heard without understanding their meaning” (Symonds, 1953, p. 3). The deficit in auditory comprehension is secondary to a dissociation between accurate phonological and semantic information (Bormann & Weiller, 2012; Kohn & Friedman, 1986). Auditory comprehension is abnormal, but comprehension of written and picture stimuli is normal. Word-meaning deafness usually occurs in cases of transcortical sensory aphasia, Wernicke’s aphasia and conduction aphasia of mild severity.

3. Echo-answer refers to the superfluous incorporation of words from the question in the response, whereas contamination is the inadvertent inclusion of a word just heard into the patient’s response instead of the one he/she wanted to say (Lebrun et al., 1971). These phenomena often coexist with ME.

4. Four major types of repetition performance were observed. At times, single words were echoed correctly, apparently without awareness of the reiterated item for the followed continued and usually unsuccessful attempts to reproduce the echoed word. At other times, a word was repeated correctly with uncertainty or surprise on the performance. More commonly, repetition showed phonemic paraphasia. Verbal paraphasia was rarely observed. Finally, repetition occasionally was characterized by complete failure. These four responses ranged from the most automatic to 'the most “voluntary”' (Brown, 1975, p. 39).

Additional information

Funding

The study was supported by Lundbeck Spain and Denmark. MJTP (FPU14/04021) and KTH (FPU15/06512) have been funded by a PhD scholarship from the Spanish Ministry of Education, Culture and Sport under the FPU program. DLB has been supported by the “Juan de la Cierva” program (FJCI-2014-22953) of the Spanish Ministry of Economy and Competitiveness.