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THE ROLE OF OBSTRUCTIVE SLEEP APNEA SYNDROME IN THE PATHOGENESIS AND EVOLUTION OF DEMENTIA
Full text linkABSTRACT
Premessa e scopo. Il sonno è coinvolto nel mantenimento dell’ integrità anatomica e funzioni cerebrale attraverso meccanismi diversi, tra cui la promozione della plasticità sinaptica, il consolidamento della memoria e l'attività scavenger. Studi epidemiologici suggeriscono che la sindrome delle apnee ostruttive del sonno (OSAS) può aumentare il rischio di deterioramento cognitivo. Una conoscenza più approfondita del legame fisiopatologico tra OSAS e demenza e la dimostrazione che l’OSAS è in grado di influenzare direttamente lo sviluppo di alterazioni cognitive, potrebbe portare ad un miglioramento delle strategie di prevenzione e trattamento. L'obiettivo principale di questo studio è stato quello di valutare la correlazione tra deficit cognitivo e la presenza / gravità dell’OSAS, così come la possibile influenza di fattori vascolari.
Soggetti e metodi. Sono stati arruolati 41 soggetti senza demenza affetti da OSAS, diagnosticata con una polisonnografia. Al basale, tutti i soggetti sono stati sottoposti ad uno screening vascolare completo e standardizzato, incluso uno studio della reattività cerebrovascolare mediante il calcolo dell’indice di apnea volontaria (BHI) sulla base della valutazione con Doppler transcranico. E’ stata inoltre eseguita una valutazione neuropsicologica per studiare i principali domini cognitivi. Come controlli, sono sati arruolati e sottoposti allo stesso protocollo di valutazione vascolare e cognitiva soggetti con caratteristiche anagrafiche simili, non affetti da OSAS. Tutti i pazienti con OSAS sono stati sottoposti al miglior protocollo di trattamento in base alle raccomandazioni delle linee guida internazionali e rivalutati dopo 6 mesi. In questo momento, ogni paziente ha ripetuto gli esami polisomnografici, neuropsicologici e ultrasonografici.
Risultati. Al basale, le prestazioni cognitive erano più basse nei pazienti rispetto ai controlli nei seguenti compiti: Stroop test T1 e T2 e E1 ed E2 (p = 0,001), test delle parole di Rey per l’apprendimento verbale a breve termine / lungo termine (p = 0,0001 e 0,001, rispettivamente) e test di fluenza semantica e fonetica (p = 0,001). Considerando la reattività cerebrovascolare, una differenza significativa tra pazienti e controlli era presente per il BHI medio (p <0.05). Alla valutazione a 6 mesi, sulla base dei risultati del confronto tra le due valutazioni polisonnografiche, 21 pazienti presentavano un miglioramento della gravità dell’OSAS (gruppo 1) e 20 erano rimasti stabili (gruppo 2). Nel gruppo 1 è stato trovato un miglioramento significativo nel BHI sinistro (p = 0.001) e medio (p = 0.001) e nel test delle parole di Rey per l’apprendimento verbale a breve termine (p = 0.02) e a lungo termine (p = 0,001). Nessun cambiamento nella reattività cerebrovascolare e nel profilo cognitivo è stato rilevato nei pazienti del gruppo.
Conclusioni. Il dato più significativo di questo studio riguarda la dimostrazione di una significativa associazione tra OSAS e riduzione dell’efficienza in alcuni compiti cognitivi in pazienti senza una storia di demenza. Il legame tra la riduzione delle prestazioni cognitive e le alterazioni emodinamiche cerebrali suggerisce un possibile ruolo patogenetico di una condizione circolatoria sfavorevole nel sostenere la disfunzione cerebrale nell’OSAS. La possibilità di migliorare le alterazioni vascolari e cognitive con trattamenti specifici merita una attenta considerazione per una strategia terapeutica completa e tempestiva nei pazienti con OSAS al fine di ridurre il rischio di sviluppo di un deterioramento cognitivo
Can Framingham Risk Score predict cognitive decline progression in Alzheimer’s Disease ?
No full textBackground and Aims: The role of vascular factors in influencing cognitive
decline has been extensively investigated, and some difficulties in
defining their weight in dementia pathogenesis emerged. Aim of the study
was to investigate, in a population of Alzheimers Disease (AD) patients, the
relevance of the Framingham cardiovascular risk profile (FCRP) in influencing
cognitive deterioration.
Patients and Methods: 284 consecutive AD patients were enrolled. For
each patient, FCRP score was calculated. APOE alleles were evaluated in
order to assess genetic predisposition do develop a more aggressive cognitive
deterioration. We performed a one-year-follow-up in order to quantify
the cognitive decline by the Clinical Dementia Rating score changes.
Results: FCPR score predicted cognitive deterioration with an AUC of
0.63 (95%CI: 0.57-0.69; p<0.0001). In the sub-population of patients with
a genetic increased predisposition to develop cognitive deterioration, and
with an advanced vascular impairment, FRCP predictive value significantly
increased with an AUC of 0.77 (95%CI: 0.52-0.93; p<0.05). Our findings
show that FCRP, a cluster of vascular risk factors, can predict the progression
of deterioration in AD patients. This was particularly evident in patients
with major genetic and atherosclerotic risk factors
Cerebral haemodynamics and cognitive deterioration in bilateral asymptomatic severe carotid stenosis
No full textBackground and Purpose: We aimed to evaluate cognitive performance during a 3-year period in subjects with bilateral asymptomatic severe internal carotid artery stenosis and to explore the role of cerebral hemodynamics and atherosclerotic disease in the development of cognitive dysfunction. Methods: 159 subjects with bilateral asymptomatic severe internal carotid ar- tery stenosis were included and prospectively evaluated for a 3-year period. At entry, demographics, vascular risk profile and pharmacological treatments were defined. Cognitive status was evaluated using the Mini-Mental State Ex- amination (MMSE) at baseline and at follow-up. Cerebral hemodynamics was assessed by transcranial Doppler–based breath-holding index test. As a mea- sure of the extent of systemic atherosclerotic disease, common carotid artery intima-media thickness was measured. A cutoff for pathological values was set at 0.69 for breath-holding index and 1.0 mm for intima-media thickness. Results: The risk of decreasing in MMSE score increased progressively from patients with bilaterally normal to those with unilaterally abnormal breath-holding index, reaching the highest probability in patients with bi- laterally abnormal breath-holding index (P<0.0001). Pathological values of intima-media thickness did not influence the risk of MMSE score change. Conclusions: Our findings suggest that patients with asymptomatic bi- lateral severe internal carotid artery stenosis may be at risk of developing cognitive impairment. The evaluation of the hemodynamic status, besides providing insights about the possible mechanism behind the cognitive dys- function present in carotid atherosclerotic disease, may be of help for the individuation of subjects deserving earlier and more aggressive treatments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cardiovascular and genetic determinants of cognitive deterioration in Alzheimer's Disease
No full textIntroduction: We aimed to evaluate the association between non-valvular
atrial fibrillation(NVAF), vascular disease and cognitive impairment. We
assessed if NVAF was associated to a larger atherosclerotic burden and a
faster progression of dementia in patients with Alzheimer’s disease(AD).
Materials and Methods: All subjects with mild-moderate AD followed by
our clinic were enrolled. At baseline we collected data regarding clinical
history and drug therapy. Framingham cardiovascular risk profile(FCRP)
and mini-mental state examination(MMSE) were calculated. APOE genotype
and carotid ultrasound were also assessed. Subjects were followed-up
at 24 months with a neuropsychological evaluation and classified as stable
or worsened to severe AD. Evolution to severe AD was considered as the
main outcome. Statistic was calculated with GLM/multivariate models and
binary logistic regression.
Results: 310 consecutive patients affected by mild-moderate AD were finally
included. NVAF was associated to a lower entry MMSE score, a higher
mean IMT and a higher FCRP.APOE ε4 allele carriers with NVAF had
the lowest MMSE (14.90±7.62), the highest mean IMT (1.16±0.17 mm)
and the highest FCRP(26.24±3.96%). This group was also associated to the
highest risk of clinical evolution to severe AD (OR: 1.749; 95%CI: 1.255-
2.437; p=0.001).
Conclusion: Despite optimal anticoagulation, NVAF identified a subset of
AD patients with a larger atherosclerotic burden and worse cognitive performance.
The interaction between NVAF and ApoE ε4 genotype detected
a subgroup with the highest vascular risk, the poorest cognitive function at
the beginning of the study and the highest risk of evolution to severe AD
in 24 months
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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