Compensational Strategies for a Merchant After Stroke With Anosognosia for Alexia Without Agraphia

Abstract

We report the first case, to our knowledge, of successful return to work of a patient with alexia without agraphia. This case is also interesting as it is the first report of which we are aware of anosogosia for alexia without agraphia: the patient confabulated when asked to read English text, but immediately stated that he could not read Chinese text because he did not know that language. The selective nature of this confabulation would not be inconsistent with anosognosia being one of the brain’s responses to absence of afferent information.

A 56-year-old right-handed gentleman, a small business merchant, presented to the emergency department with a complaint of 2 days of left hand/arm sensory loss. He was found to have left hemisensory deficit, visual field cut and neglect, and poor gait. A computed tomography scan showed a large right occipital temporal infarction. Follow-up magnetic resonance imaging/magnetic resonance angiography showed a large right occipital infarct with extension into the thalamus, splenium of the corpus callosum, and temporal lobe secondary to a right posterior cerebral artery occlusion (Figure 1A and B). Examination showed left visual–spatial neglect and inattention and reduced insight into his deficits, but no aphasia, dyscalculia anomia, or right visual field impairment. He matched colors to exemplars and named the color of common objects—for example, when asked what color a banana is, he responded “yellow”—but he did not correctly verbally name or write most colors that were shown to him visually. The patient could not read, but he could write. Sensory and gait disturbances and hemispatial neglect resolved; medical treatment was optimized and the patient was discharged home.

Figure 1.

Lesion of the right thalamus and splenium of corpus callosum. (B) Large right occipital-temporal lesion.

The gentleman could write normally spontaneously or from oral dictation, but he could not read or copy what he had just written, the text being presented in his right visual field. The patient also had anosognosia for his alexia. For example, when shown a headline describing the result of a sports event, the patient said that the headline said “Looks like rain today.” When told that he had read the text incorrectly, he routinely blamed it on poor vision. The patient’s anosognosia for alexia was quite specific: When shown English, French, or mirror reversed English and asked to read it, he confidently responded by saying what he thought the text said, but his account was completely false. Conversely, when shown a page of Chinese print the patient immediately laughed and said, “That’s Chinese, I cannot read it!”

The patient was the primary income earner for his family, selling items such as newspapers, magazines, foodstuffs, and other small goods. At follow-up, the patient and family complained of 2 critical problems preventing his much needed return to work: making change for transactions and retrieving items requested by customers. For oral calculations, the patient performed outstandingly. However, when we asked what the change would be from a purchase of 2 newspapers, the patient produced a calculator from his bag, performed a calculation, and gave a clearly incorrect answer. We told the patient to henceforth perform cost/change calculations without recourse to paper or a calculator. To avoid having to retrieve items such as magazines by reading their titles, we told the family to arrange given items at the store in predetermined locations so that the patient could use his intact spatial memory to retrieve them on a customer’s request. The patient successfully returned to independent work using these strategies.

In 1892, Dejerine ¹ most presciently ^2,3 described alexia without agraphia in a right-handed patient with lesions in the left occipital lobe and splenium of the corpus callosum. Dejerine explained the alexia as stemming from the left visual cortex being destroyed and the inability of the right visual cortex to transfer its information to the speech centers in the left brain. Agraphia is absent since the language and motor centers are intact. A small percentage of right-handed individuals have language centers in the right brain, and this is the most parsimonious explanation of our patient’s deficits and preserved abilities. ⁴ We have not seen anosognosia for alexia without agraphia previously reported. Indeed, alexia can often be a patient’s presenting complaint. These findings suggest that in this case, and perhaps in others, anosognosia is one of the brain’s responses to the absence of afferent information—a form of selective Anton’s syndrome for written material in one language script. Our patient confabulates as to why he is not able to read English text. Because his vision is intact and he is not a speaker of Asian languages, he ascribes his inability to lack of knowledge of Chinese, whereas he cannot do so with English text, emphasizing the highly selective nature of confabulatory responses.