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Calculation disturbances in adults with focal hemispheric damage.

It has been suggested that hemisphere-damaged patients with calculation disorders can be subdivided into 3 groups: agraphia or alexia for numbers, spatial dyscalculia and anarithmetia. The purpose of the present study was to evaluate the role played by visuospatial disorders and by anarithmetia in subjects with impaired calculation abilities. Seventy-six patients with focal hemispheric lesions and 26 normal controls with demonstrated ability to read and write numbers were given a written calculation task, the Token Test, the Crosses Test, a test of Constructional Apraxia and Ravens Progressive Matrices. In the calculation task, a quantitative score represented the number of digits that were correct numerically and put in correct position. A qualitative score with emphasis on visuospatial factors was obtained by scoring each problem with the criteria used in Bentons Visual Retention Test. Analysis of the results showed that both left and right hemisphere-damaged patients performed significantly worse than controls and that patients with left posterior lesions were particularly impaired even after correction of the acalculia scores by the results of the other neuropsychological tests. These results suggest that even though different factors may contribute to calculation disorders (impairment of intelligence, visuoconstructive difficulties and above all aphasia), left posterior lesions are particularly prone to produce an impairment in calculating abilities which is partially independent from the above disorders.

Right posterior brain-damaged patients are poor at assessing the age of a face

The ability to order unknown faces by age was investigated in right and left brain-damaged patients, divided into posterior and non-posterior groups on the basis of CT scan findings. A face recognition test and a figure ground discrimination test were also given. All three tests were affected by brain damage, but their sensitivity to the locus and side of lesion varied. While no hemispheric difference was found on the figure ground discrimination test, the face age test significantly discriminated patients with right posterior injury from any other brain-damaged group. The face recognition test occupied an intermediate position, with right posterior patients significantly impaired in comparison with right non-posterior patients and marginally impaired with respect to left posterior patients. Aphasia did not affect the performance of left brain-damaged patients on any of the tests. The findings are interpreted as evidence that damage of the right posterior hemisphere areas disrupts the structural encoding of visual information. Four prosopagnosic patients were also tested. Only those showing signs of apperceptive agnosia failed on the face age test.

Amyotrophic lateral sclerosis: Prognostic indicators of survival

Amyotrophic lateral sclerosis (ALS) has a fatal outcome in about three years, but survival is known to vary considerably, making it difficult to predict disease duration in individual cases. The aim of this study was to investigate possible early prognostic factors of ALS survival. We included 123 probable or definite cases of ALS, with disease onset between 1989 and 1998, and with a follow‐up of at least one year. Survival functions were obtained using both the Kaplan‐Meier and the actuarial methods. Subgroups, formed on the basis of gender, area of residence, work, and age at and site of onset, were compared using the logrank test and Coxs proportional hazards method (survival functions), and applying the Grizzle, Starmer, Koch (1969), and Koch, Johnson, Tolley (1972) methods (one‐year survival probability trends). The survival curves dipped sharply in the first three years, followed by a flattening trend, with 50% of patients dying within 2.5 years, and 89% over seven years. The clinical form with lower limb onset was associated with longer survival than the upper limb onset and bulbar forms (median survival: 39, 27, and 25 months, respectively). Survival was also affected by age at onset (median survival: 34, 27, and 23 months for onset <60, 60–75, and >75 years, respectively), area of residence (median survival: 24 months in mountainous areas, 32 elsewhere), and type of work (median survival: 25 months in agricultural workers, 33.5 in others). Gender did not influence survival, whereas percutaneous endoscopic gastrostomy placement and invasive ventilation did. The estimation of individual ALS survival is important to allow the patient to plan for his future and to make optimal use of medical and community resources. Although age at and site of onset, area of residence, and agricultural work were found to influence survival, there remains an unexplained heterogeneous progression of the disease, suggesting the influence of other, as yet unknown, prognostic factors. The identification of a definite set of prognostic factors may allow physicians to make more reliable survival predictions at diagnosis.

Learning and forgetting processes in Parkinson's disease:: A model-based approach to disentangling storage, retention and retrieval contributions

Learning and forgetting a prose passage was studied in 20 patients with Parkinsons disease and in 20 normal control subjects by means of stochastic models, with the aim of identifying the learning and retaining abilities that are affected by Parkinsons disease. Results suggested that Parkinsons disease patients are impaired in developing automatic processing both during learning and retaining, while functions that require active attention are spared. The automatic/intentional dissociation, which is the hallmark of motor disturbance in Parkinsons disease, extends to memory abilities, and, on the grounds of neuroanatomical, neurochemical and neurophysiological correlates, suggests that the memory deficit in Parkinsons disease may be contingent on a dysfunction of the medial prefrontal-cingulate cortex.

Hemisphere asymmetry for imitation of hand and finger movements, Goldenberg's hypothesis reworked.

Goldenberg and co-workers put forward the hypothesis that coding of hand gestures with respect to body parts depends upon the functioning of the left hemisphere while the right hemisphere would be involved in imitation of finger postures. They supported this claim with experimental evidence from lesion studies, however, they failed to back it up with functional neuroimaging data. To verify Goldenbergs hypothesis on hemisphere asymmetries for hand/finger postures imitation, the performance of 35 patients with left hemisphere lesion (L/pts), of 24 patients with right hemisphere lesion (R/pts) and that of 41 matched controls was assessed in two imitation tasks, respectively, taxing hand or finger postures. The data, adjusted for the performance of the controls and for the effect of age were analysed using a multivariate, nonparametric approach. The outcome partly supports Goldenberg and colleagues hypothesis: hand minus finger performance did differs between the R/pts and L/pts patients, even considering the pertinent hand-finger performances by control participants, however, in line with neuroimaging evidence, the left hemispheres contribution is greater than that of the right for both finger and hand posture imitation.

Contrasting performance of right- and left-hemisphere patients on short-term and long-term sequential visual memory

Abstract Fifty control subjects and 100 patients with damage restricted to one hemisphere were given two memory tests, one requiring immediate recognition of increasingly longer sequences of pictures and the second learning to criterion the order of presentation of eight pictures. On the short-term memory test, left- but not right-brain-damaged patients scored significantly lower than controls. Their inferiority disappeared when the means were corrected for Token Test scores. On the learning test, right-brain-damaged patients performed more poorly than controls and failed to reach criterion in a significantly higher proportion than left-brain-damaged patients. When the standardized scores on the two tests were compared, the left hemisphere group was found to perform more poorly on the short-term than on the long-term memory test, while the right-brain-damaged group showed the opposite pattern. It was concluded that the aid provided by the verbal code in sequential memory for pictures is limited to conditions requiring brief storage, while long-lasting acquisition of a pictorial sequence is mainly mediated by visual images.

Parkinson's Disease Affects Automatic and Spares Intentional Verbal Learning a Stochastic Approach to Explicit Learning Processes

We studied word list and paired associates learning in patients with idiopathic Parkinsons disease and normal controls by means of a two-stage stochastic model, which allows independent measurements of encoding, storage and retrieval abilities. We preliminarily ascertained that the model components were both sufficient and necessary to account for the overall performance of the subjects, and then compared the learning abilities between the two groups. Parkinsons disease patients were selectively impaired in identifying well-known engrams, for which learning is superfluous, and in automatic retrieval, namely in abilities that do not need attentional effort. By contrast, they were unimpaired in encoding and intentional retrieval, which require a purposeful effort. The automatic-voluntary dissociation of Parkinsons disease patients motor behaviour is, therefore, paralleled by some features of their memory performance.

Intellectual and memory impairment in moderate and heavy drinkers.

Heavy drinkers (more than 2 liters of wine per day), without clinical evidence of brain dysfunction, moderate drinkers (1 liter of wine per day) and control subjects (no more than 250 cc of wine per day) were given the Progressive Matrices test and two learning tests, one tapping verbal memory and the other spatial memory. Heavy drinkers performance was significantly worse than that of the other groups on the Progressive Matrices test and the spatial learning test. With a more lenient method of analysis, the difference between heavy drinkers and controls on the verbal learning test and that between moderate drinkers and controls on the Progressive Matrices test were also significant. When the influence of intelligence on memory performance was partialled out by covarying memory scores for Progressive Matrices scores, all differences on the verbal learning test disappeared whereas the spatial learning test still discriminated heavy drinkers from mild drinkers and controls. The bearing of these findings on the continuum of impairment hypothesis and the right hemisphere vulnerability hypothesis is discussed.

Verbal learning strategies in Parkinson's disease

: Word-list learning was studied in patients with Parkinsons disease (PD) and normal control (NC) participants by means of the selective-reminding procedure of H. Buschke and P. A. Fuld (1974) in 3 learning conditions using semantically unrelated items; semantically related items, whose implicit categorical structure had to be spontaneously guessed; and semantically related items, whose explicit categorical structure was known in advance. The PD patients displayed poor learning in all 3 conditions. To identify the functional locus of the PD patients deficits, the authors performed a stochastic Markov chain analysis, which allowed individual measurements of encoding, retrieval, and category clustering abilities. PD patients were never significantly impaired in encoding word engrams; their impairment was confined to automatic and intentional retrieval and to the ability to benefit from explicit semantic clues.

Recollection of public events in healthy people: A latent-variable stochastic approach to disentangling retrieval and storage☆

Recollection of media-mediated past events was examined in 96 healthy participants to investigate the interaction between the age of the subject and the age of memories. The results provided evidence that people older than 75 years recall recent events significantly worse than remote ones. Younger participants (47-60 years old) showed the reverse pattern. The implementation of a Markov chains latent-variable stochastic model suggested that reduced efficiency of retrieval rather than storage processes accounts for these results. The findings were interpreted with reference to models of memory trace consolidation, assuming that memory for past public events is dependent on hippocampal structures.