The syndrome of senile gait

Timed Up and Go test and gastrointestinal disorders among hospitalized older adults with fall risk

PURPOSE OF THE RESEARCH

The study aimed to examine the correlation between underlying medical conditions and gait analysis parameters as well as determine the key determiners of fall risk.

MATERIALS AND METHODS

This was a cross-sectional study. A total of 120 hospitalized older adults, recruited from a medical center in northern Taiwan, completed three instruments: the Timed Up and Go (TUG) test, a demographic questionnaire, and the Morse Fall Scale. The inferential statistics were subjected to the chi-square test, Mann-Whitney U test, Kruskal-Wallis test, and Spearman's rank correlation coefficient analysis to determine the correlations among the demographic variables, gait analysis parameters, and fall risk in elderly inpatients. Logistic regression was used to analyze the predictors of elderly inpatients' fall risk.

RESULTS

The results showed that longer TUG test times, slower walking speeds, or shorter stride lengths are related to higher fall risk. The new finding was that longer TUG test times and slow gait speeds were correlated with lower gastrointestinal as well as hepatobiliary and pancreatic diseases.

CONCLUSIONS

This study confirms that gait analysis parameters are significantly correlated with fall risk among older inpatients and that TUG is an important indicator of frailty, prefrailty, or metabolic state. Early detection of the symptoms of gastrointestinal disorders and the provision of adequate nutrition could potentially improve inpatients' gait and prevent falls.

Case Report on Fear of Falling Syndrome: A Debilitating but Curable Gait Disorder

Patient: Male, 70

Final Diagnosis: Fear of falling syndrome

Symptoms: Inability to get up from a chair and ambulate independently

Medication: —

Clinical Procedure: Lumbar puncture

Specialty: Neurology

Essential pitfalls in "essential" tremor

Although essential tremor has been considered the most common movement disorder, it has largely remained a diagnosis of exclusion: many tremor and nontremor features must be absent for the clinical diagnosis to stand. The clinical features of "essential tremor" overlap with or may be part of other tremor disorders and, not surprisingly, this prevalent familial disorder has remained without a gene identified, without a consistent natural history, and without an acceptable pathology or pathophysiologic underpinning. The collective evidence suggests that under the rubric of essential tremor there exists multiple unique diseases, some of which represent cerebellar dysfunction, but for which there is no intrinsic "essence" other than a common oscillatory behavior on posture and action. One approach may be to use the term essential tremor only as a transitional node in the deep phenotyping of tremor disorders based on historical, phenomenological, and neurophysiological features to facilitate its etiologic diagnosis or serve for future gene- and biomarker-discovery efforts. This approach deemphasizes essential tremor as a diagnostic entity and facilitates the understanding of the underlying disorders to develop biologically tailored diagnostic and therapeutic strategies. © 2017 International Parkinson and Movement Disorder Society.

Quantifying effects of age on balance and gait with inertial sensors in community-dwelling healthy adults

Although balance and gait deteriorate as a person ages, it is unknown if all balance and gait measures change similarly across the adult age span. We developed the Instrumented Stand and Walk test (ISAW) to provide a quick quantification of key components of balance and walking: postural sway, anticipatory postural adjustments during step initiation, gait, and turning using body-worn, inertial sensors. Our aims were to characterize how different balance and gait measures change with age and to identify key age-related measures of mobility, in a wide age range of healthy, community-dwelling adults. A total of 135 healthy, community-dwelling subjects of age range 21-89years with no history of falls were enrolled. Subjects wore inertial sensors on the wrists, ankles, sternum and lumbar area; 37 reliable and valid measures of postural sway, step initiation, gait and turning were computed. Univariate and multivariate regression analyses were performed to examine how the measures changed with age. Several distinct correlation patterns between age and ISAW measures were observed: linear deterioration, deterioration after plateau, and subtle, or no, worsening. Spatial, but not temporal, measures of gait were age-related. The strongest age correlation was found for centroidal frequency of mediolateral postural sway (r=-0.50, p≤0.001). A hierarchical regression model revealed that age was the most important predictor of mediolateral centroidal frequency, with lower sway frequencies associated with older age, independent of gender, weight, and height. Our results showed that balance and gait represent independent control systems for mobility and not all balance and gait measures deteriorate the same way with age. Postural sway during stance was more strongly related to age than any gait, gait initiation or turning measure.

Improvements in gait characteristics after intensive resistance and functional training in people with dementia: a randomised controlled trial

BACKGROUND

Preventing and rehabilitating gait disorders in people with dementia during early disease stage is of high importance for staying independent and ambulating safely. However, the evidence gathered in randomized controlled trials (RCTs) on the effectiveness of exercise training for improving spatio-temporal gait parameters in people with dementia is scarce. The aim of the present study was to determine whether a specific, standardized training regimen can improve gait characteristics in people with dementia.

METHODS

Sixty-one individuals (mean age: 81.9 years) with confirmed mild to moderate stage dementia took part in a 3-month double-blinded outpatient RCT. Subjects in the intervention group (IG) received supervised, progressive resistance and functional group training for 3 months (2 times per week for two hours) specifically developed for people with dementia. Subjects in the control group (CG) conducted a low-intensity motor placebo activity program. Gait characteristics were measured before and after the intervention period using a computerized gait analysis system (GAITRite®).

RESULTS

Adherence to the intervention was excellent, averaging 91.9% in the IG and 94.4% in the CG. The exercise training significantly improved gait speed (P < 0.001), cadence (P = 0.002), stride length (P = 0.008), stride time (P = 0.001), and double support (P = 0.001) in the IG compared to the CG. Effect sizes were large for all gait parameters that improved significantly (Cohen's d: 0.80-1.27). No improvements were found for step width (P = 0.999), step time variability (P = 0.425) and Walk-Ratio (P = 0.554). Interestingly, low baseline motor status, but not cognitive status, predicted positive training response (relative change in gait speed from baseline).

CONCLUSION

The intensive, dementia-adjusted training was feasible and improved clinically meaningful gait variables in people with dementia. The exercise program may represent a model for preventing and rehabilitating gait deficits in the target group. Further research is required for improving specific gait characteristics such as gait variability in people with dementia.

TRIAL REGISTRATION

ISRCTN49243245.

Analysis of pelvic movement in the elderly during walking using a posture monitoring system equipped with a triaxial accelerometer and a gyroscope

The incidence of falls in the elderly is increasing with the aging of society and is becoming a major public health issue. From the viewpoint of prevention of falls, it is important to evaluate the stability of the gait in the elderly people. The pelvic movement, which is a critical factor for walking stability, was analyzed using a posture monitoring system equipped with a triaxial accelerometer and a gyroscope. The subjects were 95 elderly people over 60 years of age. The criteria for instability were open-eye standing on one leg for 15s or less, and 11s or more on 3m timed up and go test. Forty subjects who did not meet both of these criteria comprised the stable group, and the remaining 55 subjects comprised the unstable group. Pelvic movement during walking was compared between the two groups. The angle, angular velocity, and acceleration were analyzed based on the wave shape derived from the device worn around the second sacral. The results indicated that pelvic movement was lower in all three directions in the unstable group compared to the stable group, and the changes in the pelvic movement during walking in unstable elderly people were also reduced. This report is the first to evaluate pelvic movement by both a triaxial accelerometer and a triaxial gyroscope simultaneously. The characteristics of pelvic movement during walking can be applied in screening to identify elderly people with instability, which is the main risk factor associated with falls.

[Gait disturbances in neurology]

Gait disorders lead to loss of mobility and therefore of an individual's autonomy. The greatest risk factor for gait disorders is old age. Other important factors include drugs and their side effects, cognitive impairment, and alcohol abuse. In successful aging there is only a slight decline in gait velocity. The classification into lower- (peripheral), middle- (spinal, basal ganglia), and higher-level gait disorders (e.g. frontal or psychogenic) is still common but contradictory. Gait disorders in neurology are frequent. Detailed descriptions of gait patterns in hypokinetic gait disorders, dystonic, hemi-, and paraparetic gait, ataxia, vestibular, neuromuscular, and psychogenic gait are given. Besides reduction of risk factors, improving the physical state (physiotherapy, sports), descriptions of walking aids, and the prevention of falls are extraordinarily important for the therapy of gait disorders.

A model-based approach for assessing parkinsonian gait and effects of levodopa and deep brain stimulation

Gait and balance disturbances are amongst the most disabling features of Parkinson's disease (PD), and are not adequately controlled with currently available medical and surgical therapies. Development of objective quantitative measures of these abnormalities would greatly help in the assessment and the development of therapeutic interventions. Recently, we developed a methodology, using dynamical system theory, for testing gait with a state-of-the-art motion-detection system (OPTOTRAK 3020, Northern Digital, Inc.). We also developed a model of the dynamics of the foot that predicts the stance and swing phase dynamics of normal walking. In the present study, we determined whether model parameters were altered in subjects with PD when they were tested on/off levodopa (LD) and on/off deep brain stimulation (DBS) in a 2 x 2 matrix.

Gait and dementia: moving beyond the notion of gait apraxia

Highest level gait disorders are produced by pathology in one or more structures in the cortical-basal ganglia-thalamocortical loop, which plays an important role in producing movements and postural synergies that meet personal desires and environmental constraints. Virtually all patients with dementia have pathology in one or more components of this loop, so highest level gait disorders are common in patients with dementia. The terminology surrounding these gait disorders is unnecessarily complex and too heavily influenced by the controversial concept of gait apraxia. Straightforward descriptive diagnostic criteria are needed. To this end, four core clinical features of highest level gait disorders are proposed: 1) inappropriate (counterproductive) or bizarre limb movement, postural synergies, and interaction with the environment, 2) qualitatively variable performance, influenced greatly by the environment and emotion, 3) hesitation and freezing, and 4) absent or inappropriate (counterproductive) rescue reactions. These core features follow logically from the physiology of the cortical-basal ganglia-thalamocortical loop and should be regarded as signs of pathology in this loop. A clinical rating scale based on these features should be developed to facilitate clinical diagnosis and clinicopathological correlation, while avoiding the ambiguities and controversies of gait apraxia.

Methodology for determining the sensitivity of swing leg toe clearance and leg length to swing leg joint angles during gait

During the swing phase of gait, the effective length of the leg-distance from the hip joint center to the toe-must be made shorter than the distance from the hip to the floor to avoid toe-stubbing or tripping while walking. Critical toe clearance occurs approximately halfway through swing phase when the distance between the toe and the floor reaches a local minimum. Analytical techniques derived in this study were used to evaluate: (1) the sensitivity of toe clearance to the swing leg hip, knee, and ankle joint angles; and (2) the sensitivity of the hip-toe distance to the swing leg knee and ankle joint angles. The toe clearance, hip-toe distance, toe clearance sensitivity (TCS), and hip-toe distance sensitivity (HTDS) were calculated for each frame of data during the swing phase of 10 able-bodied subjects. A minimum toe clearance of 1.9+/-0.5cm occurred at about 51% of the swing phase during able-bodied gait. At that particular time, the toe clearance was found to be most sensitive to the angle of the ankle (17.1cm/rad), then the hip (9.5cm/rad), and lastly the knee (2.5cm/rad). The hip-toe distance was found to be about twice as sensitive to the angle of the ankle (-15.3cm/rad) than to that of the knee (-7.6cm/rad) at the time of critical toe clearance. The methodology developed here and the baseline information calculated for able-bodied subjects could be used to evaluate the effects that different gait pathologies have on swing-phase toe clearance and hip-toe distance.

Insights into age-related locomotor declines from studies of insects

Locomotor deficits frequently accompany aging in animals. These deficits are often caused by degeneration in the nervous and musculoskeletal systems. Insects are an excellent model for age-related behavior studies because they are short-lived and have a reduced nervous system with fewer cells than vertebrates. Furthermore, they are highly mobile and display a complex set of locomotor behaviors. This review presents research that has examined age-related locomotor deficits in insects and discusses the value of these studies to understand aging processes in all animals.

Alzheimer's disease with and without cerebral infarcts

OBJECTIVE

To compare the clinical and pathological features of Alzheimer's disease (AD) patients with and without associated cerebral infarcts (CI).

METHODS

The consecutive records of 57 prospectively studied demented patients fulfilling the CERAD criteria for the pathological diagnosis of AD were reviewed. Cases with cortical Lewy bodies were excluded. CI were found in 22 cases (39%) (AD+CI group): large infarcts (5), lacunes (13) and/or hippocampal sclerosis (4), and were absent in 35 cases (AD group). Microscopic infarcts, cribiform change, amyloid angiopathy, and white matter rarefaction were not considered in this classification, but were quantified. Cortical atrophy, neurofibrillary tangle and senile plaque (diffuse and neuritic) load were also measured. Pathological evaluation was independent of clinical information. Clinical and pathological data were compared between both groups.

RESULTS

AD+CI cases were significantly older, more commonly female, less educated, and more often had blue collar occupations, sleep disturbances, frontal release signs, and EEG spikes than AD cases. Other differences found (acute/subacute onset, behavioral disturbances, and leukoaraiosis on CT scan) disappeared after controlling for age. The frequency of known vascular risk factors and focal motor and sensory signs did not differ between the groups, which showed remarkable clinical similarity overall. The only significant differences on pathological exam were hippocampal microinfarcts and white matter lesions, although there was a trend for lower neurodegenerative lesion load in the AD+CI group. The ischemic lesions were located in temporal lobe in 50% of AD+CI patients; these cases had a significantly lower neocortical neurodegenerative lesion load than those with CI in other sites.

CONCLUSIONS

The presence of CI in AD increases significantly with age, but has scarce influence on the clinical features, and cannot be predicted from common vascular risk factors. In spite of a trend, there are no major differences in neurodegenerative lesion load between AD and AD+CI groups, except when CI are located in the temporal lobe (including hippocampus), suggesting that this location may be important in the physiopathology of mixed vascular and AD dementia.

From trepidant abasia to motor network failure--gait disorders as a consequence of subcortical vascular encephalopathy (SVE): review of historical and contemporary concepts

Gait disorders in progressive subcortical vascular encephalopathy (SVE) and their impact on the burden of disability in the growing elderly population are underrepresented in medical scientific literature. The absence of a clear framework for the diagnosis and classification for gait disorders on the basis of SVE has multiple reasons: (1) neither movement disorder specialists nor stroke specialists are truly familiar with this topic and feel responsible for its treatment, (2) the existing terminology lacks a clear concept and a consistent classification, and (3) only in recent years have large prospective trials started to address the natural course of SVE. This article reviews the classical descriptions of gait disturbances with preferential view to our present concept of SVE, and comments on historical and current nosology of gait disorders aiming to propose for a new classification.

Prevalence of gait disorders in hospitalized neurological patients

The prevalence of gait disorders among neurological inpatients is unknown, although disturbed gait is a common symptom. Gait disorders often lead to loss of independence with restraints for the patients and caregivers and costs for the health system. We designed a prospective study and investigated all patients admitted to a neurological hospital during a 100-day period for the presence of a gait disorder. Clinical investigation and several disease-specific rating scales were carried out for 493 patients. In 60% of the patients, a disturbance of gait was diagnosed. Most frequent diagnoses were stroke (21%), Parkinson's disease (17%), and polyneuropathy (7%). Within these diagnoses, the rate of patients with disturbed gait was high in Parkinson's disease (93%), subcortical arteriosclerotic encephalopathy (85%), and motor neuron disease (83%). Advanced age, dementia, alcohol abuse, and treatment with antiepileptics, neuroleptics, benzodiazepines, and chemotherapeutics were identified as risk factors for a gait disorder. A decline of cognitive function was accompanied by a reduction of walking speed. According to these results, gait disorders are among the most frequent symptoms in neurology.

Comparison between the lumbar infusion and CSF tap tests to predict outcome after shunt surgery in suspected normal pressure hydrocephalus

OBJECTIVE

To compare the lumbar infusion test and the cerebrospinal fluid (CSF) tap test for predicting the outcome of shunt surgery in patients with suspected normal pressure hydrocephalus.

METHODS

68 patients with suspected normal pressure hydrocephalus were studied. The absence of preceding history indicated idiopathic disease in 75% of these. All patients were assessed twice with walking and psychometric tests before lumbar infusion test and tap test assessments. The lumbar infusion test was done using a constant infusion rate (0.80 ml/min) and regarded as positive if the steady state CSF plateau pressure reached levels of > 22 mm Hg (resistance to outflow > 14 mm Hg/ml/min). The tap test was regarded as positive if two or more of four different test items improved after CSF removal. As the variability in baseline test results was large, the better of two evaluations was used in comparisons with the results after CSF removal, as well as to evaluate the outcome after shunt surgery. Only patients with a positive lumbar infusion test or a positive tap test had surgery.

RESULTS

The results of the CSF tap test and the lumbar infusion test agreed in only 45% of the patients. Of the total cohort, 47 (69%) had positive test results and were operated on; 45 (96%) of these reported subjective improvement, and postoperative assessments verified the improvements in 38 (81%). Improvements were highly significant in walking, memory, and reaction time tests (p < 0.001). Most of the patients improved by surgery (84%) were selected by a positive lumbar infusion test, and only 42% by a positive tap test. Positive predictive values were 80% for lumbar infusion test and 94% for tap test. The false negative predictions in the operated group were much higher (58%) with the tap test than with the lumbar infusion test (16%).

CONCLUSIONS

Both the lumbar infusion test and the tap test can predict a positive outcome of shunt operations in unselected patients with suspected normal pressure hydrocephalus. The two tests are complementary and should be used together for optimal patient selection.

[Development of a clinical test of gait in frail elderly by a cognitive approach of locomotion]

OBJECTIVE

From a cognitive approach of locomotion, we studied the feasibility and the reproducibility of a clinical test of gait which is devoted to predict fall.

METHODOLOGY

With a cross-sectional design, we studied the gait of 30 old subjects (average age 82.6+/-7.1 years). The gait course consisted of a 10m length in a well light room, with regular walking shoes. Two conditions were examined: walking with and without explicit cognitive task (mental arithmetic and verbal flow task). Time (seconds) and number of steps were collected by two operators Deviations and stops were video-taped. Number of figures was recorded with a tape recorder. The difficulty to perform gait conditions was estimated by each subject with a quotation ranging from 0 (easy gait) to 10 (difficult gait).

RESULTS

Increases of time, steps, deviations and stops were observed when gait was associated to a cognitive task (6.4 seconds and 4.6 steps with mental arithmetic; 10.5 seconds and 6.7 steps with verbal flow task). All subjects managed this test. These results were reproducible across tests and operators. Walking with mental arithmetic was the most easy gait condition for subjects.

CONCLUSIONS

The simplicity and the reproducibility of this test make it as adequate instrument of gait evaluation in geriatrics. Walking with mental arithmetic is the condition that must to be used. Validation of its predictive value for fall in frail elderly subjects remains to be shown.

Movement disorders and normal aging

As the population continues to age, it has become increasingly important for clinicians to recognize the clinical characteristics of normal aging. Impaired mobility is one of the most frequent effects of normal aging, and this necessitates a specific understanding of the effects of normal aging on the motor system. This article reviews the physiological basis and clinical manifestations of normal aging as related to movement disorders. The impact of normal aging on major hypokinetic and hyperkinetic movement disorders is also discussed.

Pushing and pulling with the upper extremities while standing: the effects of mild Alzheimer dementia and Parkinson's disease

Eleven patients with mild dementia of Alzheimer type, 12 patients with mild to moderate Parkinson disease, and 27 control subjects of comparable age, education, and gender pushed or pulled on a rigid horizontal bar while maintaining stable erect stance. A target window (target force +/-10% maximum force) and a bar force cursor were displayed on a video screen, and subjects were asked to place the bar force cursor within the target window as quickly and as accurately as possible holding the target window for at least 1 sec. The target forces were 50% and 75% maximum force for each person, and three 4.0-sec push trials and three 4.0-sec pull trials were performed for each target force. Moments of force (torque), body motion, and extremity electromyography were measured with a computerized motion analysis system. The patients with Alzheimer's disease had only slightly lower Mini Mental State Examination (MMSE) scores (mean +/- standard deviation [SD] = 25.0 +/- 2.3) than the patients with Parkinson's disease (28.8 +/- 1.5) and control subjects (28.7 +/- 1.3). The patients with Alzheimer's disease had upper limb reaction times (0.827 +/- 0.399 sec) that were greater than those of the patients with Parkinson's disease (0.672 +/- 0.315 sec) and control subjects (0.606 +/- 0.263 sec). Furthermore, the patients with Alzheimer's disease achieved the designated target in only 46.2% of trials, which was comparable to the performance of the patients with Parkinson's disease (55.6%) but inferior to the control subjects (80.6%). Movement times did not differ significantly. The patients and control subjects initiated movement with comparable anticipatory postural activity in the lower limbs. The poor success rates of the patients with Alzheimer's disease and the patients with Parkinson's disease were attributable to inadequate visually guided adjustments in force after the initial movement began. This difficulty in making quick motor adjustments may be relevant to the tendency of patients with Alzheimer's disease to fall.

Walking speed and stride length predicts 36 months dependency, mortality, and institutionalization in Chinese aged 70 and older

BACKGROUND

Increasing emphasis is being placed on physical performance measures as an outcome predictor. It is uncertain whether one or two simple measurements will have predictive value compared with a battery of tests.

OBJECTIVES

To assess whether simple performance measures such as walking speed and stride length will predict dependency, mortality, and institutionalization.

DESIGN

A 3-year longitudinal study of a random sample of subjects.

SETTING

Older people living in the community in Hong Kong, Special Administrative Region, China.

SUBJECTS

A total of 2032 Chinese subjects aged 70 years and older were recruited territory-wide by proportional random sampling and followed for 3 years.

MEASUREMENTS

Functional status was measured using the Barthel Index at baseline and follow-up. The time taken to walk a distance of 16 feet and the number of steps taken were measured at baseline. Stride length is estimated by dividing 16 by the average number of steps needed to complete the walk. Outcomes regarding dependency, mortality, and institutionalization at 36 months were recorded.

RESULTS

After excluding subjects lost to follow-up and those who had died, data were available for 559 men and 612 women. Univariate analysis showed that reduced walking speed and stride length were associated with increased risk of dependency, mortality, and institutionalization. In multivariate analysis for dependency and mortality, stride length, walking speed, age, and sex were included in the best prediction model (ROC = 0.798 and 0.707, respectively), whereas only stride length was included in the prediction for institutionalization (ROC = 0.764).

CONCLUSIONS

In terms of prevention or modifying outcomes, these two simple performance measures may be used as indicators for checking for occult disease and for interventional measures such as exercise prescription.

Lamotrigine-associated rash: risk/benefit considerations in adults and children

PURPOSE

Lamotrigine (LTG) is an antiepileptic drug (AED) recently released in several countries. It is effective for a variety of seizure types in adults and children both as an add-on agent and in monotherapy, and is generally well tolerated. This report reviews the apparent risk factors for rash associated with LTG to determine whether and how the risk of serious rash can be minimized in practice.

METHODS

The panel of experts reviewed all published and unpublished data related to the incidence and risk factors for serious rash with LTG.

RESULTS

An allergic skin reaction occurs in approximately 10% of patients, usually in the first 8 weeks. Rashes leading to hospitalization, including Stevens-Johnson syndrome and hypersensitivity syndrome, occurred in approximately one of 300 adults and one of 100 children in clinical trials and appeared to be increased with overrapid titration when starting therapy and with concurrent valproate (VPA).

CONCLUSIONS

Recommendations are made for both minimizing the likelihood of serious rash and for management of rash in patients taking LTG. Risk of serious rash may possibly be lessened by strict adherence to manufacturer's dosing guidelines, particularly in patients who are at higher risk: those on concurrent VPA and in the pediatric population.

Comparative analysis of gait in Parkinson's disease, cerebellar ataxia and subcortical arteriosclerotic encephalopathy

Quantitative gait analysis has been used to elucidate characteristic features of neurological gait disturbances. Although a number of studies compared single patient groups with controls, there are only a few studies comparing gait parameters between patients with different neurological disorders affecting gait. In the present study, gait parameters were compared between control subjects, patients with parkinsonian gait due to idiopathic Parkinson's disease, subjects suffering from cerebellar ataxia and patients with gait disturbance due to subcortical arteriosclerotic encephalopathy. In addition to recording of baseline parameters during preferred walking velocity, subjects were required to vary velocity from very slow to very fast. Values of velocity and stride length from each subject were then used for linear regression analysis. Whereas all patient groups showed slower walking velocity and reduced step length compared with healthy controls when assessed during preferred walking, patients with ataxia and subcortical arteriosclerotic encephalopathy had, in addition, increased variability of amplitude and timing of steps. Regression analysis showed that with changing velocity, subjects with Parkinson's disease changed their stride length in the same proportion as that measured in controls. In contrast, patients with ataxia and subcortical arteriosclerotic encephalopathy had a disproportionate contribution of stride length when velocity was increased. Whereas the findings in patients with Parkinson's disease can be explained as a reduction of force gain, the observations for patients with ataxia and subcortical arteriosclerotic encephalopathy reflect an altered spatiotemporal gait strategy in order to compensate for instability. The similarity of gait disturbance in subcortical arteriosclerotic encephalopathy and cerebellar ataxia suggests common mechanisms.

Age-related brain changes associated with motor function in healthy older people

OBJECTIVE

To identify the MRI imaging findings associated with motor changes in healthy older people.

DESIGN

A cross-sectional study.

SETTING

A study of neurologic function in very healthy older people, the Oregon Brain Aging Study.

PARTICIPANTS

Clinical and MRI data were examined in 50 very healthy older subjects (mean age = 85.1, SD = 7.2 years).

MEASUREMENTS

Clinical measures (finger tapping, hand opening and closing, steps and time to walk 30 feet and timed standing on one foot) were dependent variables in multiple regression analyses using age and the following MRI measures as independent variables: total brain volume (TBV)/intracranial volume; ventricular volume/TBV; periventricular high signal/TBV; deep high signal/TBV.

RESULTS

The number of steps and the time to walk 30 feet were each associated with periventricular high signal (steps: r = .58, P < .001; time: r = .60, P < .001) and ventricular volume (steps: r = .54, P < .001; time: r = .58, P < .001). These associations remained significant after adjusting for age. None of the other clinical variables was associated with the MRI volumes.

CONCLUSIONS

Gait measures were associated significantly with periventricular high signal and ventricular volume. These CNS changes contribute to the cause of these important markers of aging.

Gait initiation and impairments of ground reaction forces as illustrated in old age by 'La marche à petits pas'

Ground reaction forces during gait initiation and kinematics of the first step were recorded in 11 elderly patients with idiopathic 'marche à petits pas' and 18 age-matched normal adults. Smaller values of vertical forces, and impaired amplitudes and directions of anteroposterior forces might explain start difficulties of the patients. Higher vertical displacement of the foot, and laborious establishment of the rhythm in the patients could also be related to the perturbations observed in the reaction forces. These perturbations are likely to reflect impairments of muscular synergies of the lower limbs and the lack of limb co-ordination.

Effect of age and severity of disability on short-term variation in walking speed: the Women's Health and Aging Study

Standardized objective measures of human performance have been introduced in clinical and epidemiologic studies of older populations. Reliability of these measures has usually been estimated by comparing two measures obtained in the same person. However, no information is available on variability of multiple measures collected serially over short time intervals. This study uses data from the Weekly Disability Study, a component of the Women's Health and Aging Study, to describe fluctuations in physical performance over multiple, consecutive time intervals. Walking speed was measured weekly over a 6-month period in 99 older women affected by mild to severe disability. Overall, 2120 observations were explored using techniques developed for the analysis of repeated measures. Results showed that the correlations between observations in the same person were inversely related to their separation in time. The decay in the autocorrelation function was steeper in the least disabled. However, even with 20-week separations in assessments, correlations remained above 0.6 in all age and severity of disability subgroups. Changes over time in performance differed somewhat between disability subgroups, but the relative performance across subgroups remained stable over the entire course of the study. A clear learning effect was found only in those in the middle disability subgroup. Results support the utilization of repeated measures of physical performance in research that evaluates older persons over time.

A population-based study on the association between dementia and hip fractures in 85-year olds

The association between dementia and hip fracture was studied in a representative sample of 85-year olds (N = 485). The diagnosis of dementia was made according to the DSM-III-R. The prevalence of hip fracture was obtained by history and inspection of the hip. Bone mineral density was measured with dual photon absorptiometry of the right calcaneus. Hip fracture was associated with both Alzheimer's disease (p < 0.01) and vascular dementia (p < 0.01) in women, but not in men. Among women with dementia, the rate of hip fracture was more than twice that found in the general population (32.7% vs 13.6%). Bone density was not associated with dementia or hip fracture. Body mass index and body weight were lower in women with dementia and in women with hip fracture. The prevalence of hip fracture was also increased in subjects who used psychotropic drugs, especially tricyclic antidepressants. A logistic multiple regression analysis showed that dementia, use of antidepressants and gender independently contributed to hip fracture. The reason why subjects with dementia are at increased risk for hip fractures may be that these subjects have a defective neuromuscular regulation, gait apraxia, use more antidepressants, and have a lower body mass index. Another explanation of the association may be that surgery and anesthesia give rise to systemic hypotension that leads to cerebral hypoperfusion and ischemic and neuronal death in vulnerable brain areas, and as a consequence may lead to dementia or worsen the symptoms in subjects already affected by dementia.

Gait disturbance of patients with vascular and Alzheimer-type dementias

The gaits of 15 patients with senile dementia of the Alzheimer type and 15 with vascular dementia were compared with those of 15 healthy control subjects. Patients with senile dementia showed significantly slower velocity and shorter step length than the healthy controls, and those with vascular dementia exhibited a reduction on these two variables relative to patients with senile dementia of the Alzheimer type.

Lamotrigine: an antiepileptic agent for the treatment of partial seizures

OBJECTIVE

To review the current literature on lamotrigine and its use as an antiepileptic drug (AED).

DATA SOURCES

MEDLINE and bibliographic literature searches pertaining to lamotrigine were performed. Additionally, Burroughs Wellcome provided a comprehensive bibliography, data on file, and investigator's brochure.

DATA SELECTION

The selection of reported data for this review includes both controlled and uncontrolled studies as well as case reports and unreported data from both European and US trials.

DATA SYNTHESIS

Lamotrigine is effective as an adjunctive agent in the treatment of complex and simple partial seizures with or without secondary generalization. Anecdotal reports suggest that the spectrum of activity may include other seizure types, but controlled studies substantiating these reports are needed. Lamotrigine has a favorable pharmacokinetic profile, including a long half-life, low serum protein binding, and lack of mixed-function oxidase enzyme induction. It is likely that the drug induces metabolism through the glucuronidation pathway, although probably not to a clinically significant extent. Concurrent use of enzyme-inducing AEDs increase lamotrigine's clearance, whereas valproic acid decreases it. Adverse effects are primarily central nervous system-related, with dizziness, diplopia, ataxia, and somnolence reported in at least 10% of the patients treated. The incidence of these effects is higher in patients treated concomitantly with carbamazepine and may represent a pharmacodynamic interaction. The occurrence of rash may limit lamotrigine's use and was the most common cause for discontinuation in clinical trials (2.3%). The incidence of rash is higher in patients comedicated with valproic acid.

CONCLUSIONS

Lamotrigine appears to be a safe and effective new AED for patients with refractory partial seizures when used as an adjunctive agent. It has a favorable pharmacokinetic profile allowing for once- or twice-daily dosing and adverse effects appear mild and transient. Additional studies are required to confirm efficacy in other seizure types.