Search

OBJECTIVE: To characterize the progression of the cognitive involvement in patients affected by myotonic dystrophy type 1 (DM1) by a longitudinal neuropsychological follow-up study. METHODS: In a previous study we documented an ageing-related decline of frontal and temporal cognitive functions in juvenile/adult forms of DM1, irrespectively of the n(CTG) in leukocytes and the severity of muscle weakness. Here we present the results of a neuropsychological follow-up study performed in 34 out of 70 DM1 patients previously studied. Patients were divided into four groups according to their genotype (E1:50-150; E2:150-500; E3:500-1000; E4: >1000 CTG). The neuropsychological test battery included MMSE, memory, linguistic, level, praxis, attentional and frontal-executive tasks. Statistical analysis was performed by One way MANOVA with repeated measures analysis and by Wilcoxon match paired test. RESULTS: The whole group of patients showed a significant deterioration in linguistic functions, together with a tendency towards decline in executive abilities, confirming a predominant involvement of cognitive functions subserved by fronto-temporal areas. We found no significant correlation between the progression of cognitive decline and the n(CTG) in leukocytes. Moreover, we observed that patients belonging to E2 group, with the highest mean age, got scores lower than E3 patients, with particular regard both to linguistic and executive tasks. CONCLUSIONS: These data support our previous hypothesis that the cognitive damage is confined to frontotemporal functions in adult DM1 patients, with a tendency towards a decline with aging.

X

Several authors have recently shown that anterograde amnesia is often associated with semantic memory impairment in amnesic MCI patients. Similarly, after the MCI condition, some patients who convert to Alzheimer's disease (AD) show the classic onset (cAD) characterized by the impairment of memory and executive functions, whereas other AD patients show isolated defects of episodic and semantic memory without deficits in other cognitive domains. The latter have been considered an AD variant characterized by 'focal Temporal Lobe Dysfunction' (TLD). The aim of the present study was to assess the differences in disease progression between cAD and TLD. For this purpose a continuous series of newly diagnosed probable AD patients presenting as cAD (n = 30) and TLD (n = 25), matched for severity, and 65 healthy controls underwent a comprehensive neuropsychological evaluation at baseline; TLD and cAD were re-evaluated at a 24-month follow-up. At follow-up, TLD patients showed no significant worsening of cognitive functions, whereas cAD subjects displayed a significant worsening in all explored cognitive domains. In conclusion, our results confirm that probable AD presenting as TLD represents a specific onset of AD characterized by a slower rate of progression.

According to recent criteria, Mild Cognitive Impairment (MCI) represents a clinical condition with multiple cognitive presentations (amnesic and non amnesic) that can be supported by different types of brain lesions (mainly vascular and atrophic). In order to asses if the cognitive presentation and the rate of progression differ according to the type of brain pathology, two populations of MCI patients, characterized by hippocampal atrophy (n: 39) and vascular subcortical pathology (n: 36) respectively, on the basis of MRI findings, were investigated. Patients underwent an extensive neuropsychological test battery twice (at baseline and at two years follow-up), which is made up of the MMSE and various tests of episodic memory, short-term memory, visual-spatial abilities, executive functions, language, attention, praxis and psychomotor speed. Atrophic and vascular MCI patients showed a remarkably different pattern of impairment at the baseline. The former were significantly more impaired in episodic memory tasks. The latter were more impaired in an action naming task. At the follow up examination, the rate of progression to dementia was higher in atrophic (14/39) than in vascular (5/36) MCI patients. The comparison between neuropsychological scores obtained at the baseline and at the follow-up showed that atrophic MCI patients underwent a severe decline in several cognitive domains, whereas vascular MCI patients showed a significant decline only in those tasks requiring executive abilities. Our results confirm that a selective and severe defect of episodic memory is associated with hippocampal atrophy and that MCI patients with atrophic lesions are more likely to convert to Alzheimer's type dementia while MCI patients with vascular lesions are characterized by a slight decline in executive function over time and by a tendency to develop probable vascular forms of dementia.

E200K mutation of the prion protein gene (PRNP) presented with a variety of phenotypes. A 55-year-old woman complaining of slowly progressive walking difficulties came to our observation. She showed a severe progressive ataxo-spastic syndrome but a mild cognitive impairment only. Repeated EEGs showed a diffuse slowing of the rhythm without specificity. Brain MRI revealed by FLAIR showed widespread multiple hyperintensities in the whole cerebral cortex, caudate and putamen nuclei, and in the pulvinar and medial thalamus bilaterally. These signal abnormalities were best detected by DWI with restricted diffusion on ADC map. The clinical diagnosis of possible genetic Creutzfeldt-Jakob disease (CJD) has been confirmed by PRNP gene analysis which revealed the presence of a E200K mutation. This report confirms the heterogeneity of phenotypes in E200K mutated familial CJD with the occurrence of a new phenotype not previously described.

To characterize the progression of the cognitive involvement in patients affected by myotonic dystrophy type 1 (DM1) by a longitudinal neuropsychological follow-up study.