Testing Graceful Degradation in a Patient with Aphasia

Abstract

We report an investigation of phonological priming of a picture naming task in an anomic aphasic, PB, using caffeine as a pharmacological manipulation. We compare her results to controls on a similar paradigm testing the hypothesis that qualitative results in controls would carry over to the damaged brain demonstrating a “graceful degradation” in performance. When primed with words phonologically related to a target, PB made more word retrieval failures on caffeine as a function of related primes (controls make fewer) and fewer word retrieval failures as a function of unrelated primes (controls make more). The results thus supported the rejection of the hypothesis and we conclude that the use of the pharmacological manipulation provides a sensitive test for the graceful degradation of function.

Keywords:

• Aphasia
• graceful degradation
• lesion study
• caffeine
• connectionism

Acknowledgments

The authors wish to thank Marilena Serio and Alberta Lunardelli for help with the neuropsychological testing.

Notes

*The first two authors contributed equally to this study.

¹To clarify that her word retrieval failure was an actual TOT, during the neuropsychological assessment, PB showed knowledge of some phonological information of the word she was in the TOT for; guessing the number of syllables correctly 67% of the time and initial letters 60% of the time. She was not asked for information about the word during the main study.