This syndrome was mentioned in the earlier discussion on Broca aphasia. As a result of a vascular lesion or other type of localized injury of the dominant frontal lobe, the patient loses all capacity to speak while retaining perfectly the ability to write, to understand spoken words, to read silently with comprehension, and to repeat spoken words. Right facial and brachial paresis may be associated. From the time speech becomes audible, language may be syntactically complete, showing neither loss of vocabulary nor agrammatism; or there may be varying degrees of dysarthria (hence “cortical dysarthria”), anomia, and paraphasic substitutions, especially for consonants. The most notable feature of this type of speech disorder is its transience; within a few weeks or months, language is restored to normal. Bastian, Broca, and more recently other authors called this syndrome aphemia, a term that was used originally by Broca in another context to describe the severe motor aphasia that now carries his name. Probably the syndrome is closely allied to the “mini-Broca aphasia” described earlier under “Broca Aphasia.”
The anatomic basis of pure word mutism has not been determined precisely. In a few postmortem cases, reference is made to a lesion in the Broca area. Damasio and Geschwind have stated that the lesion is anterior and superior to this area. A well studied case has been reported by LeCours and Lhermitte. Their patient uttered only a few sounds for four weeks, after which he recovered rapidly and completely. From the onset of the stroke, the patient showed no disturbance of comprehension of language or of writing. Autopsy disclosed an infarct that was confined to the cortex and subjacent white matter of the lowermost part of the precentral gyrus; the Broca area, one gyrus forward, was completely spared. Other cases have involved mainly the Broca area.
Anomic (Amnesic, Nominal) Aphasia
Some degree of word-finding difficulty is part of almost every type of language disorder, including that which occurs with the confusional states and dementia. In fact, without an element of anomia, a diagnosis of aphasia is usually incorrect. Only when this feature is the most notable aspect of language difficulty is the term anomic aphasia employed. In this condition, a relatively uncommon form of aphasia in pure form, the patient loses only the ability to name people and objects. There are pauses in speech, groping for words, circumlocution, and substitution of another word or phrase that is intended to convey the meaning. Perseveration may be prominent. Or the patient may simply fail to name a shown object, in contrast to the usual aphasic patient, who produces a paraphasic error. Less frequently used words give more trouble. When shown a series of common objects, the patient may tell of their use, or demonstrate the same, instead of giving their names. The difficulty applies not only to objects seen but also to the names of things heard or felt (as per Geschwind). In addition to displaying normal fluency of spontaneous speech and preserved comprehension and repetition, the patients we have seen with anomic aphasia have been surprisingly adept in spelling.
Beauvois and coworkers have described a form of bilateral tactile aphasia caused by a left parietooccipital lesion in which objects seen and verbally described could be named, but not those felt with either hand. Recall of the names of letters, digits, and other printed verbal material is almost invariably preserved, and immediate repetition of a spoken name is intact. That the deficit is principally one of naming is shown by the patient’s correct use of the object and, usually, by an ability to point to the correct object on hearing or seeing the name and to choose the correct name from a list. The patient’s understanding of what is heard or read is normal.
There is a tendency for patients with anomia to attribute their failure to forgetfulness or to give some other implausible excuse for the disability, suggesting that they are not completely aware of the nature of their difficulty, but some are aware of the defect. Of course, there are many more patients who fail not only to name objects but also to recognize the correct word when it is given to them. In such patients, the understanding of what is heard or read is not normal, i.e., the naming difficulty is but one symptom of another type of aphasic disorder.