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.

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 Cox's 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.

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 Goldenberg's 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 hemisphere's contribution is greater than that of the right for both finger and hand posture imitation.

Time ordering in frontal lobe patients: a stochastic model approach.

Frontal lobe patients reproduced a sequence of capital letters or abstract shapes. Immediate and delayed reproduction trials allowed the analysis of short- and long-term memory for time order by means of suitable Markov chain stochastic models. Patients were as proficient as healthy subjects on the immediate reproduction trial, thus showing spared encoding and short-term memory. They failed, instead, on the delayed trials with capital letters, but not with random shapes, suggesting that their long-term memory impairment did not depend on primary deficits for ordering, but on inability to benefit from the organisational strategies that improve the retention and retrieval in normal subjects.

Spontaneous recovery from acalculia.

A topic much considered in research on acalculia was its relationship with aphasia. Far less attention has been given to the natural course of acalculia. In this retrospective study, we examined the relationship between aphasia and acalculia in an unselected series of 98 left-brain-damaged patients and the spontaneous recovery from acalculia in 92 acalculic patients with follow-up. There was a significant association between aphasia and acalculia although 19 participants exhibited aphasia with no acalculia and six acalculia with no aphasia. We observed significant improvement between a first examination carried out between 1 and 5 months post-onset and a second examination carried out between 3 and 11 months later (mean: 5 months). The mechanisms of spontaneous recovery are discussed.

The epidemiology of ALS in Modena, Italy.

OBJECTIVE: To determine the incidence, prevalence, and mortality rates of ALS in the province of Modena, Northern Italy, from 1990 through 1999. METHODS: A retrospective epidemiologic study was conducted, ascertaining cases from all neurologic centers and hospitals of the province, death certificates, and the Italian ALS Association, section of Modena. All clinical records were reviewed, and only patients fulfilling the El Escorial revised diagnostic criteria were included. RESULTS: During the period considered (1990 to 1999), 143 residents (67 men and 76 women) entered the study. The average annual incidence was 2.16 per 100,000, with a peak in the age class of 75 to 79 years. Mean prevalence rate was 4.02 per 100,000, and mean mortality rate was 1.69 per 100,000. The incidence rate remained constant over time, whereas the prevalence and mortality rates increased owing to a rise in survival time (ALS mean duration was 17.38 months in 1990, 43.18 months in 1999). In the mountainous areas, where agricultural work is more common, the incidence, prevalence, and mortality rates were higher than in urban areas and the disease onset occurred 10 years later. Of the risk factors examined, only agricultural work and rural residence were significant. CONCLUSIONS: The incidence, prevalence, and mortality rates agree with those in recent Italian surveys and with most international studies, but the distribution of cases varied with higher rates in mountainous areas. Further prospective studies are required.