老年人衰弱原因及不良健康结局的研究进展*

老年人衰弱发生率高，并成为威胁健康结局的决定因素，为老龄化社会带来沉重的医疗负担。该文综述了衰弱的主要影响因素如社会人口学因素、身体状态、生物学状态、生活方式、心理因素，以及衰弱导致的多种不良健康结局。以期为及早启动风险预警机制，通过早期筛查、干预，减少因衰弱导致的不良健康结局提供借鉴。     

Applications of bit-mapped "cognitive" potentials (ERPs) in clinical neurophysiology--CNV complex in patients with destruction of the dorso-anteromedial bidirectional thalamo-prefrontal pathways

We discuss the most important current problems relative to the recording procedures and methods of analysis, using inter alia spatio/temporal topographic maps, of some cognitive event-related potentials (CNV complex etc.) in normal and pathological conditions. After these initial premises of neurocognitive electrophysiology, we summarize the results for 8 patients in whom we examined the effects on CNV activity formation of surgical or spontaneous bihemispheric deafferentation of prefrontal/premotor cortical associative areas. These observations bear out the hypothesis that the bidirectional homohemispheric long and short distance pathways connecting associative parieto-temporal and occipital cortical areas to the prefrontal ones, play an important role in the genesis of the long-latency cognitive event-related potentials.

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Sommario Dopo breve disamina die più importanti problemi inerenti le complesse metodiche di registrazione/analisi anche mediante mappe spazio/temporali dei più noti potenziali cognitivi ed evento-correlati (ERP), gli AA ricordano che lo studio di questi eventi bioelettrici corticali e dei processi cognitivi che essi sottendono, si complica ulteriormente se vengono presi in esame le loro modificazioni in situazioni patologiche. Tutte queste difficoltà sono la causa principale della scarsa diffusione degli ERP in campo clinico. Altro problema è quello del numero adeguato di elettrodi da utilizzare nello studio degli ERP che si formano in modo simmetrico e sincrono su estese aree corticali omologhe di entrambi gli emisferi cerebrali. Alcuni esempi illustrano questi aspetti. Gli AA. sintetizzano poi i risultati ottenuti in 8 pazienti in cui si sono esaminati gli effetti sulla formazione di varie componenti della CNV della deafferentazione chirurgica o spontanea delle aree corticali associative prefrontali da interruzione delle vie bidirezionali talamo-frontali. Queste osservazioni confermerebbero l'ipotesi che nella genesi degli ERP giocano un ruolo di fondamentale importanza le vie bidirezionali omoemisferiche che connettono le aree corticali associative parieto-temporo-occipitali con quelle prefrontali.

     

Effects of D-Met2, Pro5-enkephalinamide on pain tolerance and some cognitive functions in man

The effects ofd-Met², Pro⁵-enkephalinamide (EA) on pain tolerance and some cognitive functions have been examined in healthy male volunteers. Dihydrocodeine (DC) was used as reference substance. Applying the submaximum effort tourniquet technique EA (10 mg SC) was found to elevate the pain threshold similarly to DC (20 mg SC). Neither DC nor EA impaired the performance in the symbol cancellation test, which quantitates the intensity of attention. In this assay rather a slight improvement was detected. In addition the short-term memory performance (Wechsler test) was also improved by EA and DC. No alteration was seen in the word fluency test, an indicator of long-term (semantic) memory. The data show that EA not only improves pain tolerance but some of its mental effects are similar to those of a classical morphine congener DC.     

Effects of loprazolam on cognitive functions

The effects of oral loprazolam (1, 2 mg) on vigilance, attention, immediate memory, short-term memory, learning, long-term non-consolidated and long-term consolidated memory were determined. Twelve healthy young male volunteers were given all the treatments, placebo or loprazolam, on three different occasions, in a double-blind, random latin-square sequence, crossing over every 2 weeks. Volunteers completed a battery of tests at night, 3.5 h after drug administration, and in the morning, 10 h after drug administration, to test recall of some of the material presented at night (long-term memory) and residual effects. Loprazolam did not significantly impair any of the functions tested at night. On the other hand, 2 mg loprazolam caused impairment of long-term memory, both consolidated and not. This reduction of long-term memory does not seem to be related to the impairments of vigilance, attention or learning. The 2 mg dose of loprazolam, which did not modify the mean scores and improved vigilance, attention and learning in some of the subjects, reduced long-term memory. Therefore, although caution in interpreting the results should be used, mainly because it is possibile that differences in sensitivity of the tests cannot be overcome and because the relative small number of subjects, our results indicate that loprazolam might induce selective impairment of long-term memory. Since there were no differences between the effects on consolidated and non-consolidated memory, the amnesic effect of loprazolam seems to be due to a decrease in the storage of memory traces. There were no clear generalized residual effects in the morning after administration.     

Children with Epilepsy: The Effect of Seizures, Syndromes, and Etiological Factors on Cognitive Functioning

Summary: Overall, children with epilepsy have poorer concentration and mental processing and are less alert than age-matched controls. The relationship between cognitive functioning and epilepsy is complex, however, with widely differing degrees of intellectual impairment–ranging from minimal to severe and progressive–related to diverse types of epileptic seizures, syndromes, and etiological factors. Prolonged and frequently repeated seizures are typically associated with more severe effects on cognitive functioning, particularly if epilepsy is symptomatic, i.e., secondary to a demonstrable brain lesion. A combination of such factors may contribute to the mental deterioration seen in many children suffering from severe epilepsy.     

The role of trauma-related distractors on neural systems for working memory and emotion processing in posttraumatic stress disorder

The relevance of emotional stimuli to threat and survival confers a privileged role in their processing. In PTSD, the ability of trauma-related information to divert attention is especially pronounced. Information unrelated to the trauma may also be highly distracting when it shares perceptual features with trauma material. Our goal was to study how trauma-related environmental cues modulate working memory networks in PTSD. We examined neural activity in participants performing a visual working memory task while distracted by task-irrelevant trauma and non-trauma material. Recent post-9/11 veterans were divided into a PTSD group (n = 22) and a trauma-exposed control group (n = 20) based on the Davidson trauma scale. Using fMRI, we measured hemodynamic change in response to emotional (trauma-related) and neutral distraction presented during the active maintenance period of a delayed-response working memory task. The goal was to examine differences in functional networks associated with working memory (dorsolateral prefrontal cortex and lateral parietal cortex) and emotion processing (amygdala, ventrolateral prefrontal cortex, and fusiform gyrus). The PTSD group showed markedly different neural activity compared to the trauma-exposed control group in response to task-irrelevant visual distractors. Enhanced activity in ventral emotion processing regions was associated with trauma distractors in the PTSD group, whereas activity in brain regions associated with working memory and attention regions was disrupted by distractor stimuli independent of trauma content. Neural evidence for the impact of distraction on working memory is consistent with PTSD symptoms of hypervigilance and general distractibility during goal-directed cognitive processing.     

Cognitive bias modification - Priming with an ambiguous homograph is necessary to detect an interpretation training effect

Biases in the interpretation of ambiguous information may have a causal role in producing and maintaining anxiety. Training with repeated exposure to emotionally valenced meanings has been found to produce such a bias, as measured by lexical decisions for targets primed with related emotionally ambiguous homographs. Interpretation bias is thought to occur only when ambiguity causes competition for processing resources, but similar results might occur if valenced training causes a response bias. Twenty participants underwent training, followed by a lexical decision task with no ambiguous primes preceding the target stimuli. No training effect was found, supporting the resource competition explanation for the previous findings.     

Cognitive motor processes: The role of motor imagery in the study of motor representations

Motor imagery is viewed as a window to cognitive motor processes and particularly to motor control. Mental simulation theory [Jeannerod, M., 2001. Neural simulation of action: a unifying mechanism for motor cognition. NeuroImage 14, 103–109] stresses that cognitive motor processes such as motor imagery and action observation share the same representations as motor execution. This article presents an overview of motor imagery studies in cognitive psychology and neuroscience that support and extend predictions from mental simulation theory. In general, behavioral data as well as fMRI and TMS data demonstrate that motor areas in the brain play an important role in motor imagery. After discussing results on a close overlap between mental and actual performance durations, the review focuses specifically on studies reporting an activation of primary motor cortex during motor imagery. This focus is extended to studies on motor imagery in patients. Motor imagery is also analyzed in more applied fields such as mental training procedures in patients and athletes. These findings support the notion that mental training procedures can be applied as a therapeutic tool in rehabilitation and in applications for power training.