D. Frank Benson

Posterior Cortical Atrophy

Five patients had progressive dementia heralded by disorders of higher visual function. All eventually developed alexia, agraphia, visual agnosia, and components of Balints, Gerstmanns, and transcortical sensory aphasia syndromes. Memory, insight, and judgment were relatively preserved until late in the course. Predominant parieto-occipital atrophy was demonstrated on both computed tomography and magnetic resonance imaging in two of the patients; posterior circulation was normal by angiography in the three studied. To date, no pathologic specimen is available for study; speculations on the underlying pathologic condition include an atypical clinical variant of Alzheimers disease, a lobar atrophy analogous to Picks disease, or some previously unrecognized entity.

The human Klüver‐Bucy syndrome

Twelve patients with the Klüver-Bucy syndrome (KBS) are described. The syndrome occurred in head trauma, Alzheimers disease, Picks disease, and following herpes encephalitis. KBS was transient after head trauma but was a persistent feature of the postencephalitic syndrome. In all cases KBS was combined with aphasia, amnesia, or dementia. Human KBS resembles the monkey syndrome, but in humans there is a more elaborate complex of behavioral disturbances. The behavioral manifestations are produced by bilateral temporal lobe dysfunction. Partial expression of the syndrome may have localizing validity.

Fluency in Aphasia: Correlation with Radioactive Scan Localization

Summary The obvious differences in verbal output of individual aphasics has been noted and an attempt made to evaluate these differences. In order to accomplish this a set of variable characteristics of aphasic speech was described. There were ten such features; rate of speaking, prosody, pronunciation, phrase length, effort, pauses, press of speech, perseveration, word use and paraphasia. It was noted that certain of these characteristics occurred together naturally so that two distinct clusters of clinical features were outlined. 100 aphasic patients were then studied, each of the characteristics being rated separately and it was found that the majority of patients (64%) readily fell into one of the two groups. Correlation of these two clinical groups with the underlying anatomical lesion was obtained through use of radioisotope brain scan results. Almost without exception the lesion producing one cluster of characteristics was located anterior to the Fissure of Rolando while the other cluster had a posterior lesion. The cluster with the anterior lesion had speech characterized by low verbal output, dysprosody, dysarthria, considerable effort and predominant use of substantive words while the posterior group were normal or near normal in all these features but often had paraphasia, press of speech and a distinct lack of substantive words. Thus it was felt that an anterior or posterior localization could be realiably diagnosed in many cases of aphasia based solely on the characteristics of verbal output. Several significant exceptions to this simple clinical observation were noted.

Interictal memory and language impairment in temporal lobe epilepsy

Memory and language were evaluated in patients with temporal lobe epilepsy and generalized epilepsy. Subjects were matched for age, duration of illness, and seizure frequency, and grouped according to the electroencephalographic results and seizure type into right temporal, left temporal, and generalized. In formal tests of intelligence, auditory and visual memory, and language, a significant difference was noted only on a confrontation naming test. The mean score on this test was considerably lower in the left temporal group; right temporal and generalized groups scored in the normal range. This decrement correlated with impairment on many verbal subtests of intelligence and memory. These results suggest that the interictal memory impairment of temporal lobe epilepsy may be an anomia and that the anomia may contribute to impairment of verbal learning and memory; both circumlocution and circumstantiality may compensate for anomia.

Disturbances in Constructional Ability

Summary Twenty-four subjects with positive radioactive brain scans in one of four quadrants of the brain (right anterior, right posterior, left anterior, left posterior) and 16 patients with no evidence of focal brain damage were tested on a battery of six tests to assess constructional ability over as broad a spectrum as possible. These tests included: (1) visual and auditory reaction time, (2) drawing to memory and to copy, (3) puzzle constructions, (4) stick-pattern reversals, (5) template-matching, and (6) token-patterns. Differences were found between groups dependent upon cerebral lateralization of lesion (i.e., right versus left hemisphere damage), position of lesion site within the hemisphere (i.e., anterior versus posterior), and the nature of the task being utilized. We find that constructional disability cannot be considered a single, unitary disturbance, but is, rather, a function of various factors in combination with each other. There is evidence that lesions in right hemisphere produce more consistent disturbances in visual-spatial tasks than do similar lesions in left hemisphere, and that there is a greater consistency of performance with posterior lesions (in either hemisphere) than with anteriorly located lesions. An historical review of research in constructional disability (apraxia) is presented, as well as some speculations pertaining to the nature of the disturbance, based on present and earlier findings.

Neurologic Correlates of Anomia

Publisher Summary This chapter discusses anomia and outlines involved neuroanatomical structures and pathways. Anatomical-clinical correlations for the varieties of anomia described are suggested and a neurologic framework for the word-finding process described. Almost every individual with aphasia has some reduction in the repertoire of words available for speech and requires more time than normal to produce words in response to either pictures or questions. The problem of producing words appears to be universal in aphasia, but word-finding problems also occur in normal individuals and in many types of cerebral dysfunction. Anomia is a state in which a person has a problem with word-finding. The presence of anomia may be conspicuous in spontaneous or conversational speech. In aphasia output, one of two distinctly different naming problems may be apparent. In one, the patient appears to have a problem saying the word while in the second he appears to have a problem knowing the word desired. There is another word-finding problem that is noted in the conversational speech of fluent aphasia. These patients produce a rambling, noninformative output, containing many words but conveying comparatively little information. A pure anomic aphasia—one with no other disturbance of output and no problems in comprehension, repetition, reading, or writing—can be called word selection anomia. The patient fails to name objects on confrontation, but readily explains or demonstrates their use, proving that he recognizes the object but cannot produce the verbal symbol. In clinical practice, a mixture of several varieties of anomia is frequent, but differentiation can often be made, particularly when related clinical signs are taken into account.

THE AMNESIC SYNDROME OF POSTERIOR CEREBRAL ARTERY OCCLUSION

Ten patients who suffered an acute onset of amnesia associated with either unilateral or bilateral visual field defects are described. Clinical evaluation pointed to infarction in the posterior cerebral artery territory in each case. The posterior cerebral artery supplies medial temporal structures (including hippocampus), and infarction in this region is presumably responsible for the amnesia. Amnesia occurring as a symptom of a stroke was thus strongly linked to posterior cerebral artery occlusion. Amnesia is usually said to require bilateral lesions but four cases in the present series appeared to have unilateral (left‐sided) occlusion. There are several reports in the literature of amnesia following either left posterior cerebral artery occlusion or left temporal lobectomy. The question of unilateral vs. bilateral damage in the genesis of amnesic states is discussed in relation to this left‐sided preponderance and in the context of the common origin of both posterior cerebral arteries. From present evidence it is concluded that lesions confined to the left side may cause temporary amnesia, but that the evidence for permanent amnesia is inconclusive.

Aphasia type and aging

Abstract We analyzed the relationship between age and clinical type of aphasia in 167 right-handed men who had suffered cerebrovascular accidents. Patients with unequivocal diagnoses as Brocas, Wernickes, anomic, conduction, and global aphasics were considered. The median age of the Brocas group (51 years old) was significantly lower than that of the total group (55.8 years old), while the median age of the Wernickes group was significantly higher (63 years old). Moreover the incidence of Wernickes aphasia increased steadily with age, while incidence of the other types of aphasia peaked in the sixth decade and then diminished with increasing age.

The temporal pattern of retrograde amnesia in Korsakoff's disease

A multiple-choice questionnaire about well-known public events of the past 50 years, grouped with respect to time, was administered to 11 alcoholic patients with Korsakoffs disease and to 50 normal individuals of comparable age and background. Normal persons perform quite well on questions of the recent past and fall off only slightly when tested for more remote memories. In contrast, patients with Korsakoffs disease do very poorly in remembering recent events but improve to normal levels when memories become more remote. This confirms classical clinical observation and raises some important points about the mechanism of memory.

Acalculia: acquired anarithmetia.

Summary Traditionally, three varieties of acalculia are discussed: (1) aphasic acalculia, in which number language is disturbed; (2) visuo-spatial acalculia, in which alignment and place-holding values are abnormal; (3) anarithmetia, a disturbance of the basic ability to perform computations. a single case is presented which demonstrates a mild but significant calculating disorder. The incomplete nature of the calculating disturbance allows considerable analysis into the underlying disability and there is clear evidence that neither language nor visuo-spatial disability has produced this acalculia. a breakdown of the ability to perform higher computational processes is demonstrated, warrants use of the term anarithmetia and allows some conjecture concerning the source of this unusual problem.