Potentially modifiable determinants of malnutrition in older adults: A systematic review.

BACKGROUND & AIMS: Malnutrition in older adults results in significant personal, social, and economic burden. To combat this complex, multifactorial issue, evidence-based knowledge is needed on the modifiable determinants of malnutrition. Systematic reviews of prospective studies are lacking in this area; therefore, the aim of this systematic review was to investigate the modifiable determinants of malnutrition in older adults. METHODS: A systematic approach was taken to conduct this review. Eight databases were searched. Prospective cohort studies with participants of a mean age of 65 years or over were included. Studies were required to measure at least one determinant at baseline and malnutrition as outcome at follow-up. Study quality was assessed using a modified version of the Quality in Prognosis Studies (QUIPS) tool. Pooling of data in a meta-analysis was not possible therefore the findings of each study were synthesized narratively. A descriptive synthesis of studies was used to present results due the heterogeneity of population source and setting, definitions of determinants and outcomes. Consistency of findings was assessed using the schema: strong evidence, moderate evidence, low evidence, and conflicting evidence. RESULTS: Twenty-three studies were included in the final review. Thirty potentially modifiable determinants across seven domains (oral, psychosocial, medication and care, health, physical function, lifestyle, eating) were included. The majority of studies had a high risk of bias and were of a low quality. There is moderate evidence that hospitalisation, eating dependency, poor self-perceived health, poor physical function and poor appetite are determinants of malnutrition. Moderate evidence suggests that chewing difficulties, mouth pain, gum issues co-morbidity, visual and hearing impairments, smoking status, alcohol consumption and physical activity levels, complaints about taste of food and specific nutrient intake are not determinants of malnutrition. There is low evidence that loss of interest in life, access to meals and wheels, and modified texture diets are determinants of malnutrition. Furthermore, there is low evidence that psychological distress, anxiety, loneliness, access to transport and wellbeing, hunger and thirst are not determinants of malnutrition. There appears to be conflicting evidence that dental status, swallowing, cognitive function, depression, residential status, medication intake and/or polypharmacy, constipation, periodontal disease are determinants of malnutrition. CONCLUSION: There are multiple potentially modifiable determinants of malnutrition however strong robust evidence is lacking for the majority of determinants. Better prospective cohort studies are required. With an increasingly ageing population, targeting modifiable factors will be crucial to the effective treatment and prevention of malnutrition.

Anatomically motivated modeling of cortical laminae.

Improvements in the spatial resolution of structural and functional MRI are beginning to enable analysis of intracortical structures such as heavily myelinated layers in 3D, a prerequisite for in-vivo parcellation of individual human brains. This parcellation can only be performed precisely if the profiles used in cortical analysis are anatomically meaningful. Profiles are often constructed as traverses that are perpendicular to computed laminae. In this case they are fully determined by these laminae. The aim of this study is to evaluate models for cortical laminae used so far and to establish a new model. Methods to model the laminae used so far include constructing laminae that keep a constant distance to the cortical boundaries, so-called equidistant laminae. Another way is to compute equipotentials between the cortical boundary surfaces with the Laplace equation. The Laplace profiles resulting from the gradients to the equipotentials were often-used because of their nice mathematical properties. However, the equipotentials these Laplacian profiles are constructed from and the equidistant laminae do not follow the anatomical layers observed using high resolution MRI of cadaver brain. To remedy this problem, we introduce a novel equi-volume model that derives from work by Bok (1929). He argued that cortical segments preserve their volume, while layer thickness changes to compensate cortical folding. We incorporate this preservation of volume in our new equi-volume model to generate a three-dimensional well-adapted undistorted coordinate system of the cortex. When defined by this well-adapted coordinate system, cortical depth is anatomically meaningful. We compare isocontours from these cortical depth values to locations of myelinated bands on high-resolution ex-vivo and in-vivo three-dimensional MR images. A similar comparison was performed with equipotentials computed with the Laplace equation and with equidistant isocontours. A quantitative evaluation of the equi-volume model using measured image intensities confirms that it provides a much better fit to observed cortical layering.

Network integration: the impact of integrated delivery systems. Roundtable discussion.

One of the hottest, most competitive segments of the healthcare IS industry encompasses integration tools and systems for linking divergent, best-of-breed systems. As firms such as Healthcare Communications, HUBLink, Oacis, Software Technologies Corp., Century Analysis and Eagle Innovations vie for new contracts, CIOs and IS directors wonder about the strategic advantages of single-vendor solutions vs. the best-of-breed approach. This dynamic has driven system acquisitions for several years. More recently, 33 percent of respondents to the 1995 HIMSS/HP Survey cited integration across separate facilities as their No. 1 priority for the next two years. Clearly the emergence of integrated delivery systems and providers of continuums of care--where the cost to replace the information technologies of acquired or partnered entities remains prohibitive--will cause the market for interface engines and other integration tools to continue expanding. Following are the perceptions of a few experts on the topic. They were asked to answer two questions: 1) What are the toughest challenges faced when integrating an integrated delivery system? and 2) What are the current best practices to solving this challenge?

Cross-modal recognition of familiar and unfamiliar objects by the monkey: the effects of ablation of polysensory neocortex or of the amygdaloid complex.

Nine rhesus monkeys were trained to a standard level of cross-modal recognition (CMR) in the directions vision to touch and touch to vision. Their level of performance remained essentially unchanged with unfamiliar objects. Five then received bilateral removals of frontal, temporal and parietal polysensory cortex in one stage or successively, and 4 underwent removal of the amygdaloid complex in one stage. All animals were retrained to criterion with familiar objects and then again tested with unfamiliar objects. Postoperatively, the monkeys with extensive neocortical removals were unimpaired or slightly impaired with familiar objects, and slightly impaired (in only one direction) with unfamiliar objects. The animals with amygdaloid ablations showed a different pattern of change: with familiar objects they were unimpaired (if removals were less extensive), or were severely but transiently impaired (if the removals of the amygdala were more extensive and/or other structures were involved); with unfamiliar objects they were unimpaired, tending to improve. The neocortical polysensory areas may be necessary for generating new visual representations during learning--a performance required only for the CMR of unfamiliar objects.

Cross-modal recognition by the monkey: can the experience in the first modality be reduced to a single trial?

Using the cross-modal recognition procedure previously described, but now progressively reducing the number of learning trials given in the first sense modality, three unselected and unoperated rhesus monkeys (and one with bilateral removals of frontal, temporal and parietal polysensory cortex) were able to maintain an average level of 75% correct cross-modal recognition with only 1-3 learning trials. The pool size seemed less important than the familiarity of the objects. No discontinuity between single-trial and multiple-trial learning procedures was detected. Instead, the number of objects available at one time during learning was regarded as critical for distinguishing between these two kinds of learning procedure.

Cortical and subcortical afferent connections of the primate's temporal pole: a study of rhesus monkeys, squirrel monkeys, and marmosets.

The afferent connections of the primate's temporopolar cortex were investigated with the retrograde horseradish peroxidase technique. Old World and New World monkeys received small unilateral injections of horseradish peroxidase. These labeled cells in a number of cortical, thalamic, and brainstem regions and in a few further telencephalic and diencephalic regions. Cortically, the neighboring areas of the inferior and superior temporal gyrus and the insula contained a considerable number of labeled cells. Furthermore, a substantial projection arose from the orbitofrontal and the frontopolar cortex. The cingulate gyrus contained only very few labeled cells. Interhemispherically, corticocortical connections arose mainly from temporal lobe areas. Labeled cells were seen in various regions of the basal forebrain and cells labeled only faintly in the lateral and basal accessory nuclei of the amygdala. The claustrum contained labeled neurons only in one rhesus monkey. On the diencephalic level, the caudal medial portion of the medial pulvinar was the principal thalamic source of afferents to the temporopolar cortex. Furthermore, labeled cells were found in the neighboring, caudal part of the mediodorsal nucleus, within and along the nucleus limitans, in the medial geniculate nucleus, and in several nuclei of the nonspecific system. The fields of Forel, the zona incerta, and lateral and dorsomedial hypothalamic areas contained a few labeled cells. Within the brainstem of the rhesus monkeys those regions projecting diffusely to the cortex contained a few labeled neurons. Furthermore, these brains had some labeled cells in the regions of the nuclei medialis annuli aqueductus, tractus mesencephalicus nervi trigemini, and trochlearis. Although among the three species differences in the cortical and thalamic projection patterns were observed, the regions projecting most densely to the temporal pole were similar in principle. This statement holds in particular for cortical and thalamic sites. However, the greatest number of labeled cells was found in the rhesus monkey, a fact that cannot be attributed solely to the size of the horseradish peroxidase injections and the size of the brain, but that appears rather to represent a true species difference. From our results we conclude that the temporopolar cortex constitutes a cortical area necessary for effective affectional-sensory integration.

Consequences of serial cortical, hippocampal, and thalamic lesions and of different lengths of overtraining on the acquisition and retention of learning tasks.

The ability of the rat brain to acquire or to retain specific learning tasks was tested under conditions of multiple lesions and widely different amounts of practice. Lesion targets were (a) the medial prefrontal and cingulate cortex, (b) the anterior and mediodorsal thalamus, and (c) the dorsal and ventral hippocampus. Rats were divided into seven groups. The first group received lesions of all three structural complexes prior to training in a delayed alternation and an active avoidance task. Groups 2-4 received lesions in different combinations of two of the three structural complexes prior to task acquisition. Group 5 first learned both tasks and then received the medial cortical lesion; thereafter it was retrained to criterion. Then, the thalamic lesion was made, and relearning was tested a second time. Finally, the hippocampal region was damaged, and a last relearning test was given. Groups 6 and 7 also first acquired both tasks; however, after that, they received 240 (Group 6) or 1,280 (Group 7) trials of overtraining. Following this, all three structural complexes were given lesions serially before relearning of the two tasks was tested. Nine of the ten animals of Group 1 failed to acquire the alternation task, but all learned the avoidance task. In Groups 2-4, all rats acquired both tasks. Postoperatively, rats of Group 5 were inferior to those of Group 6 in both tasks, and rats of Group 7 were the most successful animals of the last three groups. These results question the assumption that serial lesions with intermittent training between lesions have beneficial effects, and they also stress the importance of task practice, that is, of behavioral experience. It is argued that prolonged training will lead to a widely distributed storage of information within the brain. The process of wide diffusion of information will, however, be disturbed (or at least retarded) by lesions made shortly after task acquisition or task reacquisition (as was the case for animals of Group 5).

Confusion of laterally inverted mirror-images: a relationship to brain anatomy?

Whereas in the monkey brain the representation of spatial direction (left/ right) is the same for visual and for tactual inflow, in the human brain visual and tactual lateral directions are not aligned with respect to one another. This anatomical feature of the human brain may account in part for the particular difficulty young sighted children have with laterally inverted forms. A small group of children who were totally blind since birth distinguished mirror pairs by touch significantly more easily than did sighted children of comparable age; and monkeys succeeded at cross-modal recognition of laterally inverted mirror pairs better (relative to control pairs) than did sighted children.

The influence of inner wall filamentousness on the performance of small- and large-caliber arterial grafts.

Dacron prostheses with differing degrees of inner wall filamentousness were implanted in the canine descending thoracic aorta for 56 days (n = 14) and the carotid arteries for 21 days (n = 40). In the thoracic aorta the healed inner capsule of 8 mm internal velour grafts was approximately three times as thick as the inner capsule of external velour knitted prostheses. However, the early patency and rapidity of healing of these two types of prostheses were essentially the same. In the carotid arteries the patency of the 4 mm external velour prostheses was greater than that of the internal velour prostheses and the mean thrombus-free surface area of the external velour grafts was significantly greater than that of the internal velour grafts. These observations suggest that an internal velour surface is not deleterious to early patency in a large-caliber, high-flow artery but that it may be in a small-caliber, low-flow artery.

Cortical and subcortical, including sensory-related, afferents to the thalamic mediodorsal nucleus of the cat.

Cortical and subcortical afferents to the cat's thalamic mediodorsal nucleus (MD) were investigated using the method of retrograde transport of horseradish peroxidase (HRP). HRP was applied using vertical or oblique approaches and either a microsyringe or implanted pipettes filled with HRP-powder. A wide variety of cortical afferents to MD was detected: Aside from afferents from the cat's classical prefrontal cortex (gyri proreus, rectus, frontalis), from adjacent areas of the premotor and cingulate cortex and from portions of the insular cortex, afferents were found from cortical areas related to the processing of somatosensory, gustatory, auditory and visual information and from portions of the parietal and temporal association cortex. A considerable number of afferents arose from the diagonal band of Broca and a small number from the precommissural septum, periamygdaloid , prepiriform , entorhinal, subicular and amygdalar regions. The preoptic region and hypothalamic areas contained some labeled cells. All brains, with the exception of one with a very small dorsomedial injection, contained labeled cells in the mamillary bodies. The reticular nuclear complex and the ventral lateral geniculate nucleus were the main sources of afferents on the thalamic level. In the brain stem the substantia nigra, the ventral tegmental area, the deep layers of the superior colliculus, pretectal and tegmental regions contained labeled cells. These results show that MD receives afferents from a large variety of structures. Among them are several cortical as well as subcortical regions related to the processing of sensory and motor information. Taken together, these connections and the numerous afferents to MD from regions related to emotional and motivational behavior confirm the view that MD has to be termed association nucleus.

The thalamic mediodorsal nucleus receives input from thalamic and cortical regions related to vision.

The mediodorsal nucleus of the thalamus (MD) so far has been regarded as being not closely connected to visual regions. Based on the method of retrograde transport of horseradish peroxidase, direct efferents to the cat's mediodorsal nucleus were demonstrated from two visual regions: from the ventral lateral geniculate nucleus and from parts of the visually responsive cortex. These projections were obtained following injections which covered most of MD, but also following injections which were restricted to medial or lateral parts and to the anterior two-thirds or merely to the center of MD. Projections from the ventral lateral geniculate nucleus arose mainly from its caudal portion; projections from the visually responsive cortex originated predominantly in area 20a, but labeled cells were also occasionally detected in areas 18 and 19.