Hans Spinnler

Dementia and working memory

This study explored the hypothesis that patients suffering from dementia of the Alzheimer type (DAT) are particularly impaired in the functioning of the Central Executive component of working memory, and that this will be reflected in the capacity of patients to perform simultaneously two concurrent tasks. DAT patients, age-matched controls and young controls were required to combine performance on a tracking task with each of three concurrent tasks, articulatory suppression, simple reaction time to a tone and auditory digit span. The difficulty of the tracking task and length of digit sequence were both adjusted so as to equate performance across the three groups when the tasks were performed alone. When digit span or concurrent RT were combined with tracking, the deterioration in performance shown by the DAT patients was particularly marked.

Dual-task performance in dysexecutive and nondysexecutive patients with a frontal lesion

Patients with defined frontal lobe lesions were assigned to 1 of 2 groups based on whether they showed a behaviorally assessed dysexecutive syndrome or were behaviorally normal. All participants were tested on dual-task performance and on 2 tasks assumed to measure frontal lobe function, the Wisconsin Card Sorting Test and verbal fluency. The dysexecutive group differed significantly from the nondysexecutive in showing impaired capacity for dual-task coordination, but there were no significant differences on the Wisconsin Card Sorting Test and verbal fluency. Results are interpreted in terms of a multicomponent central executive, whose function is linked to, but not coterminous with, the operation of the frontal lobes.

Perceptual and associative disorders of visual recognition Relationship to the side of the cerebral lesion

IN 1890, Lissauerl described the first welldocumented case of visual agnosia and proposed a subdivision of this disorder into an apperceptive and an associative form, according to which stage of the process of visual recognition was primarily af€ected. By apperception he meavt the higher level of processing of sense data (the lower level being designated as perception) which enables the subject to identify and discriminate complex patterns. In Lissauers opinion, this impairment can be evaluated by requiring the patient to [I] describe the formal features of the pattern, [2] reproduce it by drawing, and [3] recognize it among similar alternatives. The associative stage, on the other hand, consists of the linkage of the processed visual data with memory images laid down in the brain through other sensory modalities and with names, which Lissauer considered as the most simple and basic representation ( Vorstellung ) aroused by objects. Only through these linkages does apperception acquire a meaning. Lissauer assumed that his patient was affected by associative agnosia since he did not recognize objects, although he performed fairly well on purely apperceptive tasks such as discriminating arabesques. In the subsequent history of visual agnosia, the dichotomy between associative and apperceptive disorders has been somewhat neglected and attention has been concentrated on the content of the patterns the patient fails to recognize, distinguishing object agnosia, color agnosia, face agnosia, and others. This classifi-

Left hemisphere damage and selective impairment of auditory verbal short-term memory. A case study

The case of a left-hemisphere damaged patient with an impairment of auditory verbal memory span is described. The neuropsychological study showed a dissociation between short-term and long-term auditory verbal memory, which may be attributed to a selective defect of auditory verbal short-term memory. Since a tachistoscopic study displayed a short-term memory superiority of the left hemisphere, it can be argued that the performance for visual verbal stimuli may still be held by the left hemisphere, albeit computerized tomography showed a left-hemisphere lesion involving the whole language area.

A neuropsychological instrument adding to the description of patients with suspected cortical dementia: the Milan overall dementia assessment.

A new, short, neuropsychologically oriented test for dementia assessment--the Milan Overall Dementia Assessment (MODA)--is described. Age and education adjusted norms based on 217 healthy controls are given. A validation study on 312 outpatients suspected of dementia (121 with probable Alzheimers disease) showed that the MODA differentiated patients with cognitive impairment from normal subjects more effectively than did the DSM III-R. The correlation between the MODA and the mini mental state examination was 0.63 in controls and 0.84 in patients with Alzheimers dementia. The MODA test-retest reliability was 0.83. The test proved to be well suited to longitudinal studies.

Facial recognition in brain-damaged patients. An experimental approach.

THE FIELD OF AGNOSIA recently has been broadened by a new form which, in the opinion of many authors, possesses an individual character and a certain significance for localization: agnosia for faces or prosopagnosia. Patients with this disorder complain that they are no longer able to recognize even very familiar faces, such as those of dose relatives, without recourse to noting significant features of the face, such as a birthmark, mustache, or scar; visual details not connected with the face, such as clothing; or nonvisual characteristics, such as tone of voice. Bodamerl was the first to distinguish between this form of agnosia and object agnosia, to which it previously had been ascribed. The cases which have been described since then, as well as the interpretation given to them, recently have been summarized by Gentili and associates2 and H6caen and Angelergues.3 The explanations of the nature of this symptom may be outlined as follows: 11 Prosopagnosia is a distinctive type of agnosia caused by the impairment of a specialized perceptual ability (the recognition of human faces) which starts developing separately during the first months after birth.4 21 Prosopagnosia is not an autonomous condition, just as the other specialized forms of agnosia are not autonomous conditions. All these errors in visual recognition may be related to impairment of visual perception, which is altered quantitatively as well as qualitatively in terms of either an abnormal “Funktionswandel”5,6 or a deficit of morphosynthesis.2 A majority of the authors who have examined prosopagnostic patients, however, are skeptical that a postulated defect in visual analyzers can suffice to explain the symptom. Furthermore, HCcaen and Angelergues3 note that, in contrast to object agnosia, prosopagnosia tends to be more frequent in patients with brain damage in the right hemisphere than in those suffering from left-hemisphere damage. This suggests the existence of specialized centers for this type of recognition and makes it difficult to ascribe the disorder to a simple alteration of the sensory function. On the other hand, the prominence of prosopagnosia in patients with right-hemisphere brain damage, although evident in the cases reported by Hhcaen and Angelergue~,~ cannot be accepted without reservation. Clinical observation of the symptom might be masked by concomitant aphasia in patients suffering from left-hemisphere damage. As one studies a number of the cases described in the literature, it becomes clear that many times prosopagnosia is discovered accidentally by the physician in the course of his interview with the patient without the latter mentioning it at all. Thus, the deficit could well be overlooked in the case of aphasic patients. 31 The basic defect in prosopagnosia is the incapacity to detect the individual character of objects or stimulus patterns within a single homogenous category from the standpoint of overall f ~ r m . ~ , ~ ~ It must be noted that these patients recognize a face to be a face and fre-

A cancellation test: its reliability in assessing attentional deficits in Alzheimer's disease.

The aim of the study is to provide (i) a standardized procedure for a Cancellation Test of Digits, designed to assess in the visual modality selective attention deficits in patients with Alzheimers disease, and (ii) a detailed analysis of how patients cope with it. Age-, education-, and sex-adjusted normative scores earned by 352 healthy controls are set forth, as well as data yielded by the Digit Cancellation Test in 74 Alzheimer patients, in 26 patients with a CT-assessed frontal lobe lesion and in a group of 24 healthy subjects urged to perform the task with a shortened time-constraint. Findings include discriminant power of Alzheimer patients versus healthy controls, sensitivity to cognitive evolution of the dementing process and analysis of errors. Attention data failed to supply psychometric support for the posterior-to-anterior algorithm of progressive cortical encroachment of Alzheimers disease suggested by PET-findings. Emphasis is put on methodological aspects of neuropsychological research on Alzheimer patients and on the analysis of processing components of the tests employed. Results are discussed in the light of the relationships between psychometric assessments and related functions, and underlying neuronal degeneration.

Slowly progressive semantic impairment with category specificity

Abstract We describe the case of an architect, MF, who in his fifties presented a 10-year progressive cognitive deterioration similar to that recently classified as semantic dementia. For a long period general intelligence, non-lexical aspects of language, memory and pre-semantic stages of visual perception were spared. MF showed a lexical-semantic deficit that was more severe for living things, famous people and architectural knowledge and concerned both visual and encyclopaedic information. Visual and encyclopaedic knowledge about tools, vehicles and furniture was completely spared for a long time. On MRI, our patient presented severe atrophy of the temporal lobes, that most severely affected the right side and also involved basal neocortex, hippocampus and parahippocampal gyri.

Recency, primacy and memory: Reappraising and standardising the serial position curve

In this paper we consider the serial position curve in immediate verbal free recall. A large literature has argued that two components of the serial position curve, recency and primacy, reflect the functioning respectively of short-term and of long-term memory. However, there are a number of difficulties in interpreting the recency effect as a phenomenon uniquely associated with short-term memory. Moreover, the serial position curve has been used widely for clinical investigations in patients with memory deficits. This is despite the lack of norms for the measures derived from the curve. We present a set of standardised norms based on 321 Italian normal subjects. These norms are shown to be applicable both to an English speaking population, and to three groups of brain damaged-patients, namely Alzheimers, amnesics, and frontals. The standardised norms offer a clinical and experimental tool which, coupled with a multiple single case approach, allows us to show dissociations and double dissociations among the performance patterns obtained from all three pathological groups. The paper concludes with a discussion of a possible interpretation of the recency effect as a emergent property of all types of memory system, including verbal short-term memory. Taking into account previous literature as well as our own data, the recency effect in immediate verbal free recall is here interpreted in terms of a two-component view of verbal short-term memory.

Contrasting behavior of right and left hemisphere-damaged patients on a discriminative and a semantic task of auditory recognition.

Summary One hundred and one patients with unilateral hemispheric illness (41 right, 60 left hemisphere-damaged patients) and 49 control patients without cerebral lesions were given two non-verbal auditory recognition tasks, of which one (the Meaningless Sounds Discrimination Test) was intended to test the ability to discriminate the exact acoustic pattern of sounds, while the other (the Meaningful Sounds Identification Test) was intended to test the ability to identify the exact meaning of sounds. Patients were also given tests of visual discrimination (the Profile-Front Face Test), auditory verbal comprehension (the Token Test) and vigilance (simple visual reaction times). It was found that the right hemisphere-damaged patients were specifically impaired on the Meaningless Sounds Test, while the left hemisphere-damaged were specifically impaired on the Meaningful Sounds Test. This “double dissociation” was found to be highly significant. The Meaningless Sounds Test behaved like the visual discrimination test with respect to the side of the lesion, but, unlike this, it was not sensitive to the presence of homonimous visual field defects. Variations of vigilance apparently had no differential influence on the auditory recognition performances. Impairment on the Meaningful Sounds Test in left hemisoheredamaged patients was confined to aphasics and was highly correlated with the severity of the auditory verbal comprehension defect. Patients whose auditory recognition defect was strictly confined to either the Meaningless or the Meaningful Sounds Test were singled out. All 8 patients in the former group suffered from lesions of the right hemisphere and all 22 patients in the latter group suffered from lesions of the left hemisphere and aphasia. The former were significantly more impaired than the latter on the visual discrimination task, while the reverse occurred with tasks implying the semantic decoding of visual stimuli and with Weigl’s test of conceptual thought. The implications of these findings are discussed.