A New Validation of Montreal Cognitive Assessment on a Large Sample of Elderly Patients Undergoing Elective Orthopedic Surgery.

Objective: The hip and knee arthroplasties are reliable and suitable surgical procedures aimed at restoring the patients' functioning. The most representative age range for these replacement surgeries is between 65 and 84 years for females. With aging, the likelihood of developing cognitive deficits increases, and there is evidence that elderly patients undergoing surgery orthopedic are at higher risk of developing cognitive problems in the postoperative phase. The Montreal Cognitive Assessment (MoCA) is often used for cognitive evaluation, but different cut-offs and validations are available in the literature. Given the importance of the problem, in this work we studied a hospitalized population candidate for orthopedic surgery to determine a new specific validation of the MoCA to assess the risk of MCI. Method: We applied MoCA and Mini-Mental State Examination (MMSE) to a sample of 492 (333 women) hospitalized patients for knee (74%) or hip surgery. A non-parametric receiver operating characteristic (ROC) curve analysis was conducted to investigate the predictive accuracy of the MoCA to assess cognitive impairment, using MMSE as the gold standard. Results: A score of 22.52 gives a sensitivity of 70% and a specificity of 78%. This value is providing a more coherent diagnosis with the MMSE as compared to the other cut-offs presented in the other available validations. No differences were found between patients in terms of age and gender, suggesting a general uniformity of the selected sample. Conclusions: Deepening the coherence in MCI diagnosis between MMSE and the other MoCA's scoring considered, our new cut-off seems reasonably better than previous Italian validation on an elderly population in matching MMSE classification.

Neuropsychological and Pet Study of Depersonalization and Derealization: A Single Case Report.

The present work depicts the case of a young man suffering from a depersonalization and derealization (DD) disorder, which mainly affects his own body. When the symptoms concern something else, they almost exclusively affect living beings. Neuropsychological and neuropsychiatric studies, as well as functional neuroanatomy studies, have led to hypothesize possible relationships among cognitive-neurofunctional alterations and symptoms of depersonalization and derealization. The present study suggests that a malfunction of the left frontal and prefrontal cortex causes deficits of working memory, producing some of the symptoms of DD.

Memory performance predicts interrogative suggestibility better than global cognition in older adults with subjective cognitive complaints.

The present study aims to investigate to which extent global cognition and verbal memory can estimate interrogative suggestibility (IS) in elderly people with subjective cognitive complaints (SCCs). We used the Gudjonsson Suggestibility Scale (GSS 2) subscales (i.e., Yield 1, Yield 2 and Shift) as measures of IS. Data from a sample of consecutive patients (N = 94) who referred to neuropsychology units for the first time were collected. Our results showed that verbal memory is a better predictor of IS than global cognition. Moreover, memory impairment led to significantly higher IS independently of global cognitive status. These findings suggest that the assessment of verbal memory allows to estimate individual levels of IS better than global cognition, even in elders with objective cognitive deficits. Implications for forensic assessment of senior witnesses are discussed.

Visually evoked responses from the blind field of hemianopic patients.

Hemianopia is a visual field defect characterized by decreased vision or blindness in the contralesional visual field of both eyes. The presence of well documented above-chance unconscious behavioural responses to visual stimuli presented to the blind hemifield (blindsight) has stimulated a great deal of research on the neural basis of this important phenomenon. The present study is concerned with electrophysiological responses from the blind field. Since previous studies found that transient Visual Evoked Potentials (VEPs) are not entirely suitable for this purpose here we propose to use Steady-State VEPs (SSVEPs). A positive result would have important implications for the understanding of the neural bases of conscious vision. We carried out a passive SSVEP stimulation with healthy participants and hemianopic patients. Stimuli consisted of four black-and-white sinusoidal Gabor gratings presented one in each visual field quadrant and flickering one at a time at a 12Hz rate. To assess response reliability a Signal-to-Noise Ratio analysis was conducted together with further analyses in time and frequency domains to make comparisons between groups (healthy participants and patients), side of brain lesion (left and right) and visual fields (sighted and blind). The important overall result was that stimulus presentation to the blind hemifield yielded highly reliable responses with time and frequency features broadly similar to those found for cortical extrastriate areas in healthy controls. Moreover, in the intact hemifield of hemianopics and in healthy controls there was evidence of a role of prefrontal structures in perceptual awareness. Finally, the presence of different patterns of brain reorganization depended upon the side of lesion.

Speeded manual responses to unseen visual stimuli in hemianopic patients: what kind of blindsight?

Blindsight, i.e., unconscious visually guided behaviour triggered by stimuli presented to a cortically blind hemifield, has been typically found either by using direct (forced choice) or indirect (interhemispheric) methods. However, one would expect to find blindsight also in fast responses to suddenly appearing visual stimuli, a reminiscence of evolutionary ancient adaptive behaviour. In this study we provide preliminary evidence of this form of blindsight by using a conservative method for assessing blindsight based on a comparison between the cumulative probability functions (CPFs) of simple reaction times to blind and intact field stimuli. Furthermore, in two patients with blindsight we provided evidence that their above-chance unconscious responses were likely to be triggered by the intact hemisphere.

Odour perception following bilateral damage to the olfactory bulbs: a possible case of blind smell.

INTRODUCTION: Unconsciously detected chemicals may affect human behaviour (Kirk-Smith et al., 1983; Stern and McClintock, 1998; Zucco et al., 2009), likeability judgements (Li et al., 2007) and brain activity (Lorig et al., 1990; Sobel et al., 1999). No studies, however, have investigated blind smell - the hypothetical olfactory counterpart of blindsight (Weiskrantz et al., 1974). METHODS: In this report, free and cued olfactory identification of suprathreshold odorants varying in irritancy (i.e., low or no irritant odours versus irritant odours), and taste identification abilities, were examined in patient MB who had undergone surgery for a meningioma. Post-operative imaging revealed encephalomalacia in the left gyrus rectus, with ablation of the left olfactory bulb and damage to the right, subcortical abnormality on the left near the orbital cortex, and damage to a small section of the right gyrus rectus. RESULTS: On free identification MB, while denying a capacity to smell the odours, still correctly identified some and detected others significantly above chance. In contrast, awareness always accompanied correct detections of irritant odours. Cued odour identification was at chance and no taste impairments were observed. CONCLUSIONS: We suggest, tentatively, that MB's unusual pattern of awareness when detecting and identifying odours relative to irritant odours may represent an example of 'blind smell'.

The simon effect in schizophrenic patients with negative symptoms.

Automatic shifting of visual attention was investigated using the Simon task in schizophrenic patients with prevailing negative symptomatology. Reaction times were recorded in condition of spatial correspondence and non-correspondence between side of spatially defined responses and side of stimulus presentation. Schizophrenic patients showed asymmetries between the two hemifields attributable to a slowing down of reaction times for non-corresponding trials in the left hemifield. These results are interpreted as a deficit in the process that inhibits the automatic corresponding response, and in general as a difficulty to inhibit dependence on external stimuli, in the left hemifield/right hemisphere.