Evidence for preserved reading in 'pure alexia'.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurolinguistics

Background:

• Pure alexia, characterized by the inability to read words despite preserved vision and language comprehension, is often linked to left cerebral hemisphere damage.
• Traditional models propose a 'disconnection' between visual word recognition areas and language centers as the primary cause.

Observation:

• Four patients with pure alexia following left cerebral hemisphere infarctions were studied.
• All patients initially relied on a laborious letter-by-letter reading strategy.
• Despite reporting inability to recognize words presented briefly, patients demonstrated above-chance performance on lexical decision and semantic categorization tasks.

Findings:

• Three patients recovered some explicit word recognition ability.
• Recovered reading showed biases towards nouns over functors and high-imageability words over low-imageability words.
• Impairments in suffix processing were noted in these patients.
• Performance patterns challenge the disconnection hypothesis.

Implications:

• The findings suggest that reading in pure alexia may be supported by right-hemisphere mechanisms.
• This challenges purely disconnectionist accounts and supports models of dual-hemisphere involvement in reading.
• Further research into right-hemisphere roles in reading recovery and compensation is warranted.