Speaking in numbers as a transitional phase between mutism and Wernicke's aphasia: A report of three cases

Abstract

Background: Mutism in the context of hemispheric stroke with aphasia is rare and usually evolves to non-fluent aphasia.

Aims: We describe three multilingual and mathematically educated patients with an initial presentation of mutism, followed by a short-lasting episode of speaking in numbers as a transitional stage before developing Wernicke's aphasia. We discuss potential pathophysiological mechanisms underlying this phenomenon.

Methods & Procedures: Clinical neurolinguistic testing, including Aachen Aphasia Test and video-analysis of spontaneous speech by transcription.

Outcomes & Results: In the transitional stage between mutism and Wernicke's aphasia, numbers were randomly uttered in one or more languages, although not necessarily in the first acquired or most-used language. Number speech occurred not only in propositional speech, but also during reading and naming.

Conclusions: These patients exhibit two peculiar phenomena. First, the evolution of mutism to Wernicke's aphasia and second, the transitional phase of number speech. It is hypothesised that mutism may be more frequent in the hyperacute stages of stroke-related aphasia as a consequence of transient generalised failure of the language network. Current theories on the organisation of number magnitude and lexical retrieval of number and non-number words are discussed with reference to numerical speech. The lack of previous reports of this syndrome is probably due to the combination of the transient nature of the phenomenon and the suspected prerequisites of a specific neuro-anatomical lesion and educational background.

Keywords:

• Numbers
• Mutism
• Wernicke
• Aphasia
• Multilingual
• Stroke