Ataxia In the acute stage of the disease the ataxia of stance and gait may be so severe that the patient cannot stand or walk without support. Lesser degrees are characterized by a wide-based stance and a slow, uncertain, short-stepped gait; the mildest degrees are apparent only in tandem walking. In contrast to the gross disorder of locomotion is a relatively infrequent limb ataxia and of intention tremor; when present, they are more likely to be elicited by heel-to-knee than by finger-to-nose testing. Dysarthric, cerebellar-type scanning speech is present only rarely.
Disturbances of consciousness and mentation These occur in some form in all but 10 percent of patients who have clinical signs. From Fig. 40-1 it can also be appreciated that when there is only one sign of Wernicke disease, it is usually a confusional state. Several related types of disturbed mentation and consciousness are recognized. By far the most common disturbance is a global confusional state. The next following in frequency is memory loss discussed as follows. The patient is apathetic, inattentive, and indifferent to his surroundings. Spontaneous speech is minimal and many questions are left unanswered, or the patient may suspend conversation and drift off to sleep, although he can be aroused without difficulty. Such questions as are answered betray disorientation in time and place, misidentification of those around him, and an inability to grasp the immediate situation. Many of the patient’s remarks may be irrational and lack consistency from one moment to another. If the patient’s interest and attention can be maintained long enough to permit adequate testing, one finds that memory and learning ability are also impaired, in this way blending into the
Korsakoff state. In response to the administration of thiamine, the patient rapidly becomes more alert and attentive and more capable of taking part in mental testing. If, however, the state persists for a longer duration before thiamine is administered, the most prominent lasting abnormality becomes one of retentive memory (Korsakoff-amnesic state).
Although drowsiness is a common feature of the
Wernicke confusional state, more significant stupor and coma are rare as initial manifestations. If, however, the early signs of the disease are not recognized and the patient remains untreated, a progressive depression of the state of consciousness occurs with stupor, coma, and death in a matter of a week or two, just as occurred in Wernicke’s original cases. Autopsy series of Wernicke disease are heavily weighted with cases of this latter type, often undiagnosed during life (Harper; Torvik et al).
Some patients are alert and responsive from the time they are first seen and already show the characteristic features of the Korsakoff amnesic state. In a small number of such patients, the amnesic state is the only manifestation of the syndrome, and no ocular or ataxic signs (other than possibly nystagmus) can be discerned.
The amnesic state As indicated in Chap. 20, the core of the amnesic disorder is a defect in learning (anterograde amnesia) and a loss of past memories (retrograde amnesia). The defect in learning can be remarkably severe. The patient may be incapable, for example, of committing to memory the simplest of facts (such as the examiner’s name, the date, and the time of day) despite countless attempts; the patient can repeat each fact as it is presented, indicating that he understands what is wanted of him and that “registration” is intact, but by the time the third fact is repeated, the first may have been forgotten. However, certain nonverbal learning may take place; for example, with repeated trials, the patient may learn complex tasks such as mirror writing or how to negotiate a maze, despite no recollection of ever having been confronted with these tasks.