Cortical disorders of speech processing: Pure word deafness and auditory agnosia

Selective disorders of auditory speech processing due to brain lesions are reviewed. Over 120 years after the first anatomic report (Dejerine and Sérieux, 1898), fewer than 80 cumulative cases of generalized auditory agnosia and pure word deafness with documented brain lesions are on record. Most patients (approximately 70%) had vascular lesions. Damage is very frequently bilateral in generalized auditory agnosia, and more frequently unilateral in pure word deafness. In unilateral cases, anatomical disconnection is not a prerequisite, and disorders may be due to functional disconnection. Regardless of whether lesions are unilateral or bilateral, speech processing difficulties emerge in the presence of damage to the superior temporal regions of the language-dominant hemisphere, suggesting that speech input is processed asymmetrically at early stages already. Extant evidence does not allow establishing whether processing asymmetry originates in the primary auditory cortex or in higher associative cortices, nor whether auditory processing in the brainstem is entirely symmetric. Results are consistent with the view that the difficulty in processing auditory input characterized by quick spectral and/or temporal changes is one of the critical dimensions of the disorder. Forthcoming studies should focus on detailed audiologic, neurolinguistic, and neuroanatomic descriptions of each case.

Pure word deafness due to bilateral temporal lobe ischemic stroke occurring at different time points over the years: a case report on the insight of brain language network reorganization

Here we present a case of a native Greek male patient who presented clinically with sudden onset pure word deafness after an ischemic stroke in the temporoparietal region of the right hemisphere, but who had suffered an ischemic stroke 9 years previously in an adjacent area of the left hemisphere, causing aphasic symptoms which resolved quickly and almost completely. What makes this case interesting and novel is that it is the first case describing a patient whose ventral language comprehension circuit did not reorganize successfully due to damage of the adjacent right hemisphere language areas at a subsequent time.

Pure word deafness in a patient with bilateral ischemic stroke in the superior temporal gyrus (STG)

INTRODUCTION

Pure word deafness is a rare neurological disorder linked with an inability to comprehend speech. The precise localization of damage is still unclear.

CASE PRESENTATION

A 72-year-old woman presented with acute verbal contact disturbances, disorientation, and anxiety. In the neurological examination a slight right hemiparesis was found, together with a pure word deafness (PWD) in neuropsychological tests. Neuroimages confirmed bilateral ischemic lesions in the superior temporal gyrus (STG) acute in the left hemisphere.

CONCLUSIONS

Our case suggested that bilateral, symmetric lesions in the region of STG could cause pure world deafness. The diversity and severity of symptoms confirm the necessity of pure world deafness classification for subtypes.