Memory with emotional content, brain amygdala and Alzheimer's disease.

OBJECTIVES: A highly adaptive aspect of human memory is the enhancement of explicit, consciously accessible memory by emotional stimuli. We studied the performance of Alzheimer's disease (AD) patients and elderly controls using a memory battery with emotional content, and we correlated these results with the amygdala and hippocampus volume. METHODS: Twenty controls and 20 early AD patients were subjected to the International Affective Picture System (IAPS) and to magnetic resonance imaging-based volumetric measurements of the medial temporal lobe structures. RESULTS: The results show that excluding control group subjects with 5 or more years of schooling, both groups showed improvement with pleasant or unpleasant figures for the IAPS in an immediate free recall test. Likewise, in a delayed free recall test, both the controls and the AD group showed improvement for pleasant pictures, when education factor was not controlled. The AD group showed improvement in the immediate and delayed free recall test proportional to the medial temporal lobe structures, with no significant clinical correlation between affective valence and amygdala volume. CONCLUSION: AD patients can correctly identify emotions, at least at this early stage, but this does not improve their memory performance.

The cognitive subscale of the "Alzheimer's Disease Assessment Scale" in a Brazilian sample.

The cognitive subscale of the "Alzheimer's Disease Assessment Scale" (ADAS-Cog) is widely used for the evaluation of dementia and is very popular in dementia drug trials because of the characteristics of the scale. The objective of the present study was to adapt the ADAS-Cog for use for the Brazilian population. A major problem is that education is variable, a fact that may influence performance in cognitive evaluation. This study was conducted on a control group (CG) of 96 subjects (25 males and 71 females aged 68 +/- 8.6 years) and on 44 Alzheimer's disease (AD) patients (19 males and 25 females aged 72 +/- 6.4 years) with mild dementia (Clinical Dementia Rating score 1). For statistical analysis groups were divided into three educational levels: I, 0-4 years of schooling (65 CG/20 AD); II, 5-11 years of schooling (19 CG/7 AD), and III, 12 or more years of schooling (12 CG/17 AD). The battery was applied according to original instructions. Total mean score for CG and AD was 10.9 and 22.9 for level I, 7.8 and 22.4 for level II, and 6.2 and 15.4 for level III, respectively. These results indicate that our version of the ADAS-Cog is useful to identify mild dementia, though there may be an overlapping when comparing high education demented with low education non-demented subjects.

The cognitive subscale of the "Alzheimer's Disease Assessment Scale" in a Brazilian sample

The cognitive subscale of the "Alzheimer's Disease Assessment Scale" (ADAS-Cog) is widely used for the evaluation of dementia and is very popular in dementia drug trials because of the characteristics of the scale. The objective of the present study was to adapt the ADAS-Cog for use for the Brazilian population. A major problem is that education is variable, a fact that may influence performance in cognitive evaluation. This study was conducted on a control group (CG) of 96 subjects (25 males and 71 females aged 68 + or - 8.6 years) and on 44 Alzheimer's disease (AD) patients (19 males and 25 females aged 72 + or - 6.4 years) with mild dementia (Clinical Dementia Rating score 1). For statistical analysis groups were divided into three educational levels: I, 0-4 years of schooling (65 CG/20 AD); II, 5-11 years of schooling (19 CG/7 AD), and III, 12 or more years of schooling (12 CG/17 AD). The battery was applied according to original instructions. Total mean score for CG and AD was 10.9 and 22.9 for level I, 7.8 and 22.4 for level II, and 6.2 and 15.4 for level III, respectively. These results indicate that our version of the ADAS-Cog is useful to identify mild dementia, though there may be an overlapping when comparing high education demented with low education non-demented subjects

Median nerve SEP after a high medullary lesion. Preserved N18 and absent P14 components. Case report.

Median nerve SEPs recorded from a patient with a high medullary lesion are described. The lesion involved the anteromedial and anterolateral right upper third of the medulla, as documented by MRI. Forty one days after the lesion, left median nerve SEP showed preserved N18 and absent P14 and N20 components; stimulation of the right median nerve evoked normal responses. These findings agree with the proposition that low medullary levels are involved in the generation of the N18 component of the median nerve SEP.

Polineuropatia nutricional entre índios Xavantes / Polyneuropathy deficiency among Xavante indians

Os autores apresentam dois casos de polineuropatia carencial (PC) entre os índios Xavantes, em que o arroz era o alimento exclusivo no caso 1 e quase exclusivo no caso 2. O arroz consumido por esses índios era o beneficiado ou despolpado. A intoxicaçao pelo cianeto da mandioca ou de outros vegetais foi afastada. Relato dos Casos. Foram observados em suas aldeias dois índios com 18 e 25 anos, com história progressiva de fraqueza, diminuiçao da força muscular e emagrecimento. Removidos ao Hospital Sao Paulo, notou-se, no exame neurológico do caso 1, atrofia da musculatura distal dos membros superiores e inferiores, déficit motor distalmente com grau zero na musculatura flexora, reflexos profundos abolidos, reflexo cutâneo plantar sem resposta bilateralmente, sensibilidade, táctil, dolorosa e palestésica diminuída distalmente nos membros inferiores. No exame neurológico do caso 2, notou-se hiporreflexia proximal nos membros superiores, areflexia nas porçoes distais dos membros superiores e inferiores, hipoestesia táctil e dolorosa nos pés, hipoacusia à direita. As eletroneuromiografias mostraram anormalidades compatíveis com polineuropatia sensitivo-motora simétrica de padrao axonal desmielinizante no caso 1 e de predomínio desmielinizante no caso 2. Os exames de líquor foram normais. Discussao. A polineuropatia foi caracterizada pela história clínica, pelos exames neurológicos, eletroneuromiográficos e líquor. O diagnóstico de PC ficou estabelecido pela história clínica e pelos exames eletroneuromiográficos sugestivos de polineuropatia periférica de causa nutricional. Esta PC nao se enquadra nas mieloneuropatias como a neuropatia atáxica tropical, a paraparesia espástica e a neuropatia de Cuba. Conclusao. A PC dos Xavantes deve-se à deficiência da tiamina (vitamina B1), sendo o beribéri seco, tendo como causa o consumo do arroz beneficiado industrialmente como alimento exclusivo ou quase exclusivo. A polineuropatia dos Xavantes é diferente da neuropatia verificada ente os índios Kreen-Akrore e a observada entre os adolescentes índios do Parque do Xingu.

[Polyneuropathy deficiency among Xavante indians]. / Polineuropatia nutricional entre índios Xavantes.

UNLABELLED: The authors present two cases of polyneuropathy deficiency among Xavante indians where the sole food was rice in case 1 and almost so in case 2. The rice consumed by these indians was processed or hulled. Intoxication by cyanide from maniot or other vegetable was excluded. CASE REPORT: Two indians aged 18 and 25 years with a progressive history of weaness, decrease in muscular force and thinning were observed in their villages. On removal to the Hospital São Paulo, atrophy of the distal musculature of the upper and lower limbs, motor deficit distally with zero degree in the flexor musculature, abolished deep reflexes, plantar cutaneous reflex without response bilaterally, decreased tactile, painful and pallesthetic sensitivity distally in the lower limbs were noted on neurological examination of case 1. On neurological examination of case 2 proximal hyporeflexia in the upper limbs, areflexia in the distal portions of the upper and lower limbs, tactile and painful hypoesthesia in the feet, right hypoacousis were noted. Electromyography showed abnormalities compatible with symmetric sensorimotor polyneuropathy with an axonal demyelination pattern in case 1 and predominantly demyelinizing in case 2. Cerebrospinal fluid tests were normal. DISCUSSION: Polyneuropathy was characterized by the clinical history and by neurological, electromyographic and cerebrospinal fluid tests. The diagnosis of polyneuropathy deficiency was established by the clinical history and by electromyography suggesting peripheral polyneuropathy of nutritional origin. This neuropathy deficiency does not fit myeloneuropathies such as ataxic tropical neuropathy, spastic paraparesis and Cuba neuropathy. CONCLUSION: The Xavante polyneuropathy deficiency is caused by thiamine (vitamin B1) deficiency, that is dry beriberi, owing to consumption of industrially processed rice as sole or almost sole food. The Xavante polyneuropathy is different from the neuropathy observed among Kreen-Akrore indians and from that of adolescent indians in the Xingu Park.

Extraction of high-resolution frames from video sequences.

The human visual system appears to be capable of temporally integrating information in a video sequence in such a way that the perceived spatial resolution of a sequence appears much higher than the spatial resolution of an individual frame. While the mechanisms in the human visual system that do this are unknown, the effect is not too surprising given that temporally adjacent frames in a video sequence contain slightly different, but unique, information. This paper addresses the use of both the spatial and temporal information present in a short image sequence to create a single high-resolution video frame. A novel observation model based on motion compensated subsampling is proposed for a video sequence. Since the reconstruction problem is ill-posed, Bayesian restoration with a discontinuity-preserving prior image model is used to extract a high-resolution video still given a short low-resolution sequence. Estimates computed from a low-resolution image sequence containing a subpixel camera pan show dramatic visual and quantitative improvements over bilinear, cubic B-spline, and Bayesian single frame interpolations. Visual and quantitative improvements are also shown for an image sequence containing objects moving with independent trajectories. Finally, the video frame extraction algorithm is used for the motion-compensated scan conversion of interlaced video data, with a visual comparison to the resolution enhancement obtained from progressively scanned frames.

Stochastic modeling and estimation of multispectral image data.

Multispectral images consist of multiple channels, each containing data acquired from a different band within the frequency spectrum. Since most objects emit or reflect energy over a large spectral bandwidth, there usually exists a significant correlation between channels. Due to often harsh imaging environments, the acquired data may be degraded by both blur and noise. Simply applying a monochromatic restoration algorithm to each frequency band ignores the cross-channel correlation present within a multispectral image. A Gibbs prior is proposed for multispectral data modeled as a Markov random field, containing both spatial and spectral cliques. Spatial components of the model use a nonlinear operator to preserve discontinuities within each frequency band, while spectral components incorporate nonstationary cross-channel correlations. The multispectral model is used in a Bayesian algorithm for the restoration of color images, in which the resulting nonlinear estimates are shown to be quantitatively and visually superior to linear estimates generated by multichannel Wiener and least squares restoration.

A Bayesian approach to image expansion for improved definition.

Accurate image expansion is important in many areas of image analysis. Common methods of expansion, such as linear and spline techniques, tend to smooth the image data at edge regions. This paper introduces a method for nonlinear image expansion which preserves the discontinuities of the original image, producing an expanded image with improved definition. The maximum a posteriori (MAP) estimation techniques that are proposed for noise-free and noisy images result in the optimization of convex functionals. The expanded images produced from these methods will be shown to be aesthetically and quantitatively superior to images expanded by the standard methods of replication, linear interpolation, and cubic B-spline expansion.