Effects of age on proximal gastric motor and sensory function

BACKGROUND: Healthy aging is associated with a reduction in appetite and food intake, which may predispose to pathologic weight loss and malnutrition. Changes in intragastric mechanisms mediating satiation in the elderly have not been studied. The aim of this study was to evaluate the effects of aging on i) fasting gastric compliance and the perception of gastric distension, and ii) food intake and gastric accommodation to a meal. METHODS: Five healthy older (aged 68-73 years) and five healthy young (aged 22-27 years) men, matched for body mass index, were each studied on three occasions after an overnight fast. On one day ('barostat day'), isovolumetric and isobaric distensions of the proximal stomach were performed, and meal-induced changes in intrabag volume were measured with an electronic barostat. On another day ('tube-only day') subjects were intubated with a nasogastric tube without an intragastric bag before the meal. On the 3rd day (control day) subjects were given the meal without intubation. Energy intake from the buffet meal was quantified, and perceptions assessed using visual analogue questionnaires. RESULTS: During both isobaric and isovolumetric distensions the pressure-volume relationship did not differ significantly between older and young subjects. During gastric distensions perceptions of fullness (P < 0.01), abdominal discomfort (P < 0.05), and bloating (P < 0.05) were less in older than young subjects, whereas the perception of hunger (P < 0.05) was less in the young than in older subjects. There was no difference in energy intake (P = 0.44) between young and older subjects. Food intake was less on the barostat day (P < 0.01) and the tube-only day (P < 0.01) than on the control day in young subjects but was not affected by the different study conditions in the older subjects. After the meal the maximum intrabag volume occurred later in the older than in the young subjects (105 +/- 4 min versus 36 +/- 8 min; P < 0.05), and the intrabag volume change was greater (P = 0.05) in the older than the young subjects later in the postprandial period. CONCLUSIONS: Healthy aging is associated with decreased perception of gastric distension without any change in fasting gastric compliance and with reduced gastric tone late in the postprandial period when compared with the young. Control of food intake is less sensitive to external stimuli in older than in young subjects.     

Physiological fitness measures and sensory and motor performance in aging

This study investigated relationships between a multivariate index of physiological fitness and the degree of age-related sensory and motor performance deterioration observed in a group of 70 male subjects (age 63 +/- 12 years). Physiological fitness was determined by reducing a battery of resting pulmonary, hemodynamic and biochemical variables to a single score, the Index of Physiological Status (IPS). In addition, where possible, maximal oxygen uptake (VO2max) was predicted from submaximal values using a standard treadmill procedure. Both IPS and VO2 scores were significantly correlated with age (p less than .01). High scores on the IPS were associated with faster reaction times, improved hearing at high frequencies, greater phonatory control and improved lens accommodation. In contrast, VO2 measures were found to be insensitive to changes in sensory and motor performance. While all subjects were able to complete the tests required for the generation of the IPS, 33% of the participants were unable to complete the treadmill protocol required for estimation of VO2max. These data suggest that a simple noninvasive instrument for the evaluation of physiological fitness, which is applicable to almost all elderly subjects, may be more sensitive to age-related sensory and performance changes than more traditional exercise based measures which require the exclusion of less healthy subjects.     

Clinical examination of motor and sensory functions of the adult oral cavity

Alterations in oral motor and sensory performance are common. A traditional head and neck examination, however, does not fully assess these functions of the oral-facial region. This article presents an examination that emphasizes the clinical evaluation of oral motor and oral sensory abilities. These procedures should be considered as an addition to a routine assessment of the head and neck. An uncomplicated summary severity rating scale was developed to express the results of this examination. Two case reports demonstrate the utility of the examination in diagnosis and management of patients with oral complaints.     

Immunoglobulin levels and intellectual functioning in the aged

Abstract

Significant positive correlations between vocabulary test scores and serum levels of immunoglobulins, IgG and IgM, were obtained for 14 subjects ranging in age from 83100 years (mean 89.0 years). This positive association with vocabulary scores is a result contrary to data reported by other investigators. The interrelationship between measures of behavior, central nervous system and immunologic function deserve further attention.     

Effects of acute hyperglycaemia on anorectal motor and sensory function in diabetes mellitus.

AIMS: To determine the effects of acute hyperglycaemia on anorectal motor and sensory function in patients with diabetes mellitus. METHODS: In eight patients with Type 1, and 10 patients with Type 2 diabetes anorectal motility and sensation were evaluated on separate days while the blood glucose concentration was stabilized at either 5 mmol/l or 12 mmol/l using a glucose clamp technique. Eight healthy subjects were studied under euglycaemic conditions. Anorectal motor and sensory function was evaluated using a sleeve/sidehole catheter, incorporating a barostat bag. RESULTS: In diabetic subjects hyperglycaemia was associated with reductions in maximal (P<0.05) and plateau (P<0.05) anal squeeze pressures and the rectal pressure/volume relationship (compliance) during barostat distension (P<0.01). Hyperglycaemia had no effect on the perception of rectal distension. Apart from a reduction in rectal compliance (P<0.01) and a trend (P=0.06) for an increased number of spontaneous anal sphincter relaxations, there were no differences between the patients studied during euglycaemia when compared with healthy subjects. CONCLUSIONS: In patients with diabetes, acute hyperglycaemia inhibits external anal sphincter function and decreases rectal compliance, potentially increasing the risk of faecal incontinence.     

Effects of being born small for gestational age on long-term intellectual performance

Size at birth has been associated repeatedly with increased risk of cardiovascular morbidity and mortality later in life. However, there is accumulating evidence to suggest an association between being born small for gestational age (SGA) and increased risk of lower intelligence, poor academic performance, low social competence and behavioural problems, compared with individuals born appropriate for gestational age. Crude neurological handicaps, such as cerebral palsy, are extremely rare in children born SGA at term. Such handicaps are more common in very premature children. However, there does appear to be an increase in the risk for non-severe neurological dysfunction in individuals born SGA. Intellectual performance is evaluated in young children in several different ways, including standardized tests such as Weschler's Intelligence Scale - Revised, and teachers and parents' reports. In adulthood, indirect variables such as education and occupation are used in addition to standardized tests. It may be possible to modify the effects of SGA on intellectual development by breast feeding the baby for more than 6 months. Nutrient-enriched formula does not have any advantages when it comes to intellectual development, and induces a risk of rapid weight gain and eventually overweight. Growth hormone treatment may also have some effect on intelligence quotient.     

Effects of age and task characteristics on continuous motor tracking performance

Background/Study Context: Much has been written regarding age-related changes in sensory and motor functions, general slowing of the nervous system, and deficiencies in inhibition. Few studies, however, have attempted to define how each of these factors may contribute to poorer accuracy of motor performance with aging. The purpose of this study was to examine whether these changes were best explained by speed of task or stimulus-response compatibility. Methods: Twenty-four younger (M?=?19.5; 18-22 years) and older (M?=?72.5; 65-82 years) adults used knee movement to track a computer-generated disc along a computer-generated sinusoidal wave that either moved at 50 or 70?cm/s. Stimulus-response compatibility consisted of leg and disc movement in the same direction and stimulus-response incompatibility consisted of leg and disc movement in the opposite direction. Performance was analyzed using a mixed-design analysis of variance (ANOVA). Results: Younger adults performed better than older adults in all conditions. Magnitudes of error between the stimulus-compatible and stimulus-incompatible conditions were greater for the old group compared to the young group. Both of these findings were consistent with the hypotheses. Inconsistent with the hypothesis, speed of task did not contribute to age-related differences in accuracy of motor performance in either cognitive load conditions. Conclusion: Differences in performance could be attributed to age-related changes in selective inhibition. Future research should focus on examining the potential consequences of decreased inhibition among older adults when completing various activities of daily living and what interventions might mitigate these consequences.     

Immunoglobulin levels and intellectual functioning in the aged.

Significant positive correlations between vocabulary test scores and serum levels of immunoglobulins, IgG and IgM, were obtained for 14 subjects ranging in age from 83-100 years (mean 89.0 years). This positive association with vocabulary scores is a result contrary to data reported by other investigators. The interrelationship between measures of behavior, central nervous system and immunologic function deserve further attention.     

Blood pressure and intellectual functioning in late midlife.

To determine how much change in cognitive performance can be attributed to blood pressure status, 103 adults were assessed on two occasions approximately 11 years apart. Subjects' ages ranged from 49 to 63 years on the second occasion. Regression analyses were performed to determine how much variance in change in performance on the Digit Span, Block Design, Object Assembly, and Digit Symbol tests was accounted for by blood pressure status. Time 1 and Time 2 diastolic blood pressure, and change in hypertension medication significantly predicted Time 2 performance on the Digit Span Forward test even after Time 1 test performance, age, education, and gender were accounted for. The results further confirm the importance of assessing health functioning when studying age-related changes in cognitive performance.     

Formal education and intellectual functioning in the immigrant Cuban elderly

Formal educational experience during childhood and adolescence is an important modifier of intellectual functioning in North American elderly populations. The culture-independence of this relationship was examined with 31 immigrant Cuban elderly men and women who received their education in Cuba. The amount of formal education was significantly related to performance on measures of classification, combinatorial analysis (males only), hypothesis testing, and matrices. An index of fluid intelligence (matrices) also was significantly related to performance on the classification and hypothesis testing tasks. All participants conserved both liquid and mass, thus showing no regression on these two concerete operational tasks.     

Functional organization of motor cortex of adult macaque monkeys is altered by sensory loss in infancy

When somatosensory cortex (S1) is deprived of some of its inputs after section of ascending afferents in the dorsal columns of the spinal cord, it reorganizes to overrepresent the surviving inputs. As somatosensory cortex provides guiding sensory information to motor cortex, such sensory loss and representational reorganization could affect the development of the motor map in primary motor cortex (M1), especially if the sensory loss occurs early in development. To address this possibility, the dorsal columns of the spinal cord were sectioned between cervical levels (C3–5) 3–12 days after birth in five macaque monkeys. After 3–5 years of maturation (young adults), we determined how movements were represented in M1 contralateral to the lesion by using microelectrodes to electrically stimulate sites in M1 to evoke movements. Although the details of the motor maps in these five monkeys varied, the forelimb motor maps were abnormal. The representations of digit movements were reduced and abnormally arranged. Current levels for evoking movements from the forelimb region of M1 were in the normal range, but the lowest mean stimulation thresholds were for wrist or elbow instead of digit movements. Incomplete lesions and bilateral lesions produced fewer abnormalities. The results suggest that the development of normal motor cortex maps in M1 depends on sensory feedback from somatosensory maps.     

Influence of gender on proximal gastric motor and sensory function

OBJECTIVE: Gender-related differences have been demonstrated with regard to GI motility: gallbladder contraction, colonic transit, and gastric emptying are delayed in women. It is not known whether gender influences proximal gastric motility and perception. METHODS: We have studied the influence of gender on proximal gastric motility and perception under fasting and postprandial conditions by retrospective analysis of data obtained in 99 healthy volunteers (42 men, 57 women) who participated in barostat studies performed according to standardized protocols at the Leiden University Medical Center (Leiden, The Netherlands) between 1996 and 2000. RESULTS: Minimal distending pressure (MDP) was significantly higher in women than in men (respectively, 6.8+/-0.2 vs 5.5+/-0.2 mm Hg; p < 0.001). During stepwise pressure distensions pressure-volume curves were similar in both sexes after correction for MDP, whereas perception of fullness and abdominal pressure increased significantly (p < 0.05) more rapidly in women. Before the meal intragastric volumes (at MDP + 2 mm Hg) did not differ between sexes. After the meal gastric relaxation in the first 30 min did not differ in women and men (respectively, 186+/-23 ml and 140+/-32 ml). However, from 30 until 90 min after the meal a significantly (p < 0.05) delayed return of intragastric volume to basal was seen in women. Perception of postprandial nausea was significantly (p < 0.01) increased in women. Perception of postprandial fullness remained increased for a longer period of time in women. CONCLUSIONS: Proximal gastric motility and perception are influenced by gender. Gender-related differences in postprandial proximal gastric motility and perception should be taken into account in barostat studies comparing patients with controls.     

Pharmacotherapy for intestinal motor and sensory disorders

Motor disorders of the gastrointestinal tract are characterized by definable impairments of gut contractile function. Other conditions exhibit specific disturbances of visceral afferent and efferent activity, which may underlie selected symptom complexes. Medications in several classes have been developed to treat these disorders of gastrointestinal function. Prokinetic agents are effective therapies for ailments with reduced motor function, whereas antispasmodic drugs reduce symptoms in conditions with exaggerated pressure wave activity. Recently, medications designed to blunt transmission in visceral sensory pathways have been proposed for use in the functional bowel disorders. Finally, some patients may benefit from initiation of nonspecific therapies, which have no appreciable effect on gut motor or sensory function.