Is oral spelling recognition dependent on reading or spelling systems? dissociative evidence from two single case studies.

Recognition of orally spelt words is an unusual task, not commonly encountered in everyday life, but it can be surprising well preserved in patients with brain damage. There is, however, considerable debate over the cognitive abilities that are required to successfully perform this task. The main controversy has centred on whether oral spelling recognition is parasitic on the processes normally involved in spelling aloud or in reading. We describe a patient (FL) who showed a similar pattern of performance on reading and oral spelling recognition and was better at both tasks relative to spelling. We describe a second patient (FK) who was good at reading and reasonable at spelling but poor at reverse spelling. The patient data are not consistent with either of the following hypotheses: that oral spelling recognition is dependent either on a reading system that is functionally separate from a spelling system, or on a spelling system that is functionally separate from reading. We propose that the findings can, however, be accommodated by a model in which spelling and reading are not functionally independent systems, but share important cognitive components such as a graphemic buffer.