Gait disturbance of patients with vascular and Alzheimer-type dementias

Gait in cerebral small vessel disease, pre-dementia, and dementia: A systematic review

BACKGROUND

The interrelationships between gait, cerebral small vessel disease (CSVD), and cognitive impairments in aging are not well-understood-despite their common co-occurrence.

OBJECTIVE

To systematically review studies of gait impairment in CSVD, pre-dementia, and dementia, and to identify key gaps for future research and novel pathways toward intervention.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided search strategy was implemented in PubMed to identify relevant studies. Potential articles (n = 263) published prior to 1 December 2021 were screened by two reviewers. Studies with sample sizes >20 and including some adults over > 65 years (n = 202) were included.

RESULTS

The key findings were that (1) adverse gait and cognitive outcomes were associated with several (rather than select) CSVD pathologies distributed across the brain, and (2) poor gait and CSVD pathologies were more strongly associated with dementia with a vascular, rather than an Alzheimer's disease-related, cause.

DISCUSSION

A better understanding of the interrelationships between gait performance in CSVD, pre-dementia, and dementia requires studies examining (1) comprehensive patterns in the clinical manifestations of CSVD, (2) racially/ethnically diverse samples, (3) samples followed for extended periods of time or across the adult life span, (4) non-traditional CSVD neuroimaging markers (e.g. resting-state functional magnetic resonance imaging (fMRI)), and (5) continuous (e.g. wearable sensors) and complex (e.g. dual-task) walking performance.

Pathological Gait Signatures of Post-stroke Dementia With Toe-Off and Heel-to-Ground Angles Discriminate From Alzheimer's Disease

Given the limited power of neuropsychological tests, there is a need for a simple, reliable means, such as gait, to identify mild dementia and its subtypes. However, gait characteristics of patients with post-stroke dementia (PSD) and Alzheimer’s disease (AD) are unclear. We sought to describe their gait signatures and to explore gait parameters distinguishing PSD from post-stroke non-dementia (PSND) and patients with AD. We divided 3-month post-stroke patients into PSND and PSD groups based on the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and the activity of daily living (ADL). Thirty-one patients with AD and thirty-two healthy controls (HCs) were also recruited. Ten gait parameters in one single and two dual-task gait tests (counting-backward or naming-animals while walking) were compared among the groups, with adjustment for baseline demographic covariates and the MMSE score. The area under the receiver operating characteristic curve (AUC) was used to identify parameters discriminating PSD from individuals with PSND and AD. Patients with PSD and patients with AD showed impaired stride length, velocity, stride time, and cadence while patients with PSD had altered stance and swing phase proportions (all p ≤ 0.01, post hoc). Patients with AD had smaller toe-off (ToA) and heel-to-ground angles (HtA) (p ≤ 0.01) than HCs in dual-task gait tests. Individuals with PSD had a shorter stride length, slower velocity, and altered stance and swing phase percentages in all tests (p ≤ 0.01), but a higher coefficient of variation of stride length (CoV_SL) and time (CoV_ST) only in the naming animals-task gait test (p ≤ 0.001) than individuals with PSND. ToA and HtA in the naming animals-task gait test were smaller in individuals with AD than those with PSD (p ≤ 0.01). Statistical significance persisted after adjusting for demographic covariates, but not for MMSE. The pace and the percentage of stance or swing phase in all tests, CoV_ST in the dual-task paradigm, and CoV_SL only in the naming animals-task gait test (moderate accuracy, AUC > 0.700, p ≤ 0.01) could distinguish PSD from PSND. Furthermore, the ToA and HtA in the naming animals-task gait paradigm discriminated AD from PSD (moderate accuracy, AUC > 0.700, p ≤ 0.01). Thus, specific gait characteristics could allow early identification of PSD and may allow non-invasive discrimination between PSD and AD, or even other subtypes of dementia.

Preexisting dementia is associated with higher mortality rate in patients with femoral neck fracture

OBJECTIVE

This study aimed to assess the mortality and the influence of age, Abbreviated Mental Test (AMT) scores, and American Society of Anesthesiologists (ASA) grades on patients with dementia and femoral neck fracture (FNF) at 30 days, 4 months, 1 year, and 2 years after undergoing surgery.

METHODS

Of 1296 patients admitted with FNF, 180 had had prefracture dementia. A retrospective study of these 180 patients was carried out. The patient demographics, including age, sex, presence of diabetes mellitus (DM), lipid profile, AMT score, preoperative comorbidities, ASA grade, and incidence of postoperative delirium, were documented.

RESULTS

A total of 113 patients (62.8%) died postoperatively. The mortality rate was 17.7% (20 patients) at 30 days, 54.9% (62 patients) at 4 months, 77.9% (88 patients) at 1 year, and 87.6% (99 patients) at 2 years. The mortally rate in dementia with FNF was three times higher than that in FNF without dementia and was independent of age, ASA grades, DM, lipid profile, AMT scores, and development of postoperative delirium.

CONCLUSIONS

Dementia should be a principal predictive factor in mortality of FNF and should be a key determinant in all frailty scores.

Posturographic analysis of older adults without dementia and patients with Alzheimer's disease: A cross-sectional study

Additional clinical tools should be investigated to facilitate and aid the early diagnosis of cognitive decline. Postural control worsens with aging and this may be related to pathological cognitive impairment.

The Role of Movement Analysis in Diagnosing and Monitoring Neurodegenerative Conditions: Insights from Gait and Postural Control

Quantifying gait and postural control adds valuable information that aids in understanding neurological conditions where motor symptoms predominate and cause considerable functional impairment. Disease-specific clinical scales exist; however, they are often susceptible to subjectivity, and can lack sensitivity when identifying subtle gait and postural impairments in prodromal cohorts and longitudinally to document disease progression. Numerous devices are available to objectively quantify a range of measurement outcomes pertaining to gait and postural control; however, efforts are required to standardise and harmonise approaches that are specific to the neurological condition and clinical assessment. Tools are urgently needed that address a number of unmet needs in neurological practice. Namely, these include timely and accurate diagnosis; disease stratification; risk prediction; tracking disease progression; and decision making for intervention optimisation and maximising therapeutic response (such as medication selection, disease staging, and targeted support). Using some recent examples of research across a range of relevant neurological conditions-including Parkinson's disease, ataxia, and dementia-we will illustrate evidence that supports progress against these unmet clinical needs. We summarise the novel 'big data' approaches that utilise data mining and machine learning techniques to improve disease classification and risk prediction, and conclude with recommendations for future direction.

Dementia

Dementia is a syndrome seen most commonly in older people and characterized by a decline in cognitive performance which impacts on the person's ability to function. There are approximately 47 million people worldwide with dementia and there are 10 million new cases every year. It is a major cause of disability and dependence and impacts on the physical, psychologic, and social well-being of families and carers. Alzheimer's disease is the most common form of dementia. Gait and balance impairments are common in people with dementia and contribute to the significantly elevated risk of falls. Older people with dementia are at increased risk of injury, institutionalization, hospitalization, morbidity, and death after a fall. There is preliminary evidence, predominantly from relatively small studies, that falls and disability can be prevented in this population. However, more good-quality research is needed, both to provide some certainty around the existing evidence base as well as to explore alternate approaches to prevention, including combined cognitive-motor training and cognitive pharmacotherapy.

Ambulatory Gait Behavior in Patients With Dementia: A Comparison With Parkinson's Disease

Accelerometry-based gait analysis is a promising approach in obtaining insightful information on the gait characteristics of patients with neurological disorders such as dementia and Parkinson's disease (PD). In order to improve its practical use outside the laboratory or hospital, it is required to design new metrics capable of quantifying ambulatory gait and their extraction procedures from long-term acceleration data. This paper presents a gait analysis method developed for such a purpose. Our system is based on a single trunk-mounted accelerometer and analytical algorithm for the assessment of gait behavior that may be context dependent. The algorithm consists of the detection of gait peaks from acceleration data and the analysis of multimodal patterns in the relationship between gait cycle and vertical gait acceleration. A set of six new measures can be obtained by applying the algorithm to a 24-h motion signal. To examine the performance and utility of our method, we recorded acceleration data from 13 healthy, 26 PD, and 26 mild cognitive impairment or dementia subjects. Each patient group was further classified into two, comprising 13 members each, according to the severity of the disease, and the gait behavior of the five groups was compared. We found that the normal, PD, and MCI/dementia groups show characteristic walking patterns which can be distinguished from one another by the developed gait measure set. We also examined conventional parameters such as gait acceleration, gait cycle, and gait variability, but failed to reproduce the distinct differences among the five groups. These findings suggest that the proposed gait analysis may be useful in capturing disease-specific gait features in a community setting.

Physical activity and behaviour in dementia

Physical activity can have a positive impact on cognition and well-being in older people. This article reviews and evaluates the effects of planned physical activity programmes on mood, sleep and functional ability in people with dementia. A total of 27 studies between 1974 and 2005 were found. Of these, four included participants living at home, two involved participants who were living either at home or in care homes and 21 included participants living solely in care homes. Since psychosocial intervention can reduce family caregiver burden, the break down of home-care and associated rates of institutionalization, the indirect effects of these physical activity programmes on the family caregiver are also explored. The scope for developing physical activity programmes for people with dementia in primary care using families and volunteers is discussed.

Dementia and hip fractures: development of a pathogenic framework for understanding and studying risk

Dementia and hip fractures are 2 conditions that are seen primarily in older adults, and both are associated with substantial morbidity and mortality. An individual with dementia is up to 3 times more likely than a cognitively intact older adult to sustain a hip fracture. This may occur via several mechanisms, including (1) risk factors that are common to both outcomes; (2) the presence of dementia increasing hip fracture incidence via intermediate risk factors, such as falls, osteoporosis, and vitamin D; and (3) treatment of dementia causing side effects that increase hip fracture risk. We describe a model that applies these 3 mechanisms to explain the relationship between dementia and hip fractures. Comprehensive understanding of these pathways and their relative influence on the outcome of hip fracture will guide the development of effective interventions and potentially improve prevention efforts.

Effect of a vocal choice reaction time task on the kinematics of the first recovery step after a sudden underfoot perturbation during gait

Thirty-two healthy young adults (15 women) were tested for their ability to maintain their comfortable step pattern following an unpredictable underfoot perturbation in the presence and absence of a concurrent vocal choice reaction time task. Custom instrumented shoes were used to randomly deliver an unexpected medial or lateral forefoot perturbation that inverted the mid-foot an average of 10° or everted the midfoot an average of 9° during one stance phase of a gait trial. Medial and lateral perturbations were randomized between left and right feet in 12 of 30 gait trials. The results of the repeated measures analyses of variance show that, compared to the step parameters of unperturbed gait, the administration of the unexpected underfoot perturbation did not significantly lead to alterations in the step length or width of the first recovery step. In addition, the simultaneous administration of a vocal choice reaction time task with the underfoot perturbation did not significantly affect the kinematics of the first recovery step. We conclude that in young healthy adults an unexpected 9-10° underfoot perturbation, with or without a vocal reaction time task, will not affect their recovery step kinematics when walking at a comfortable gait speed.

[Gait changes as an early indicator of dementia]

Gait disorders are more common in dementia than in the context of the physiological aging process. Prevalence of dementia-associated gait disturbances depends on the type of dementia and the severity of cognitive impairment. While in vascular dementia gait abnormalities are often clinically apparent at early disease stages, Alzheimer's disease patients usually have stable gait until late disease stages. With up-to-date ''brain-imaging" methods, it has been demonstrated that people suffering from dementia are more dependent on cortical activity in order to maintain gait stability in complex situations. When dysfunction of the frontal or temporal lobes occurs, allocation of these resources may no longer be sufficient. Dual-task paradigms are useful to test such resources. It has been shown in early Alzheimer's disease patients that, if the demand of attention exceeds available capacities, quantitative gait changes occur. Relevant parameters seem to be, e.g., walking speed and stride-time variability. Quantitative assessment of gait dysfunction in dementia may, thus, have the potential to serve as a trait marker.

Dementia medications and risk of falls, syncope, and related adverse events: meta-analysis of randomized controlled trials

OBJECTIVES

To evaluate the effect of cholinesterase inhibitors (ChEIs) and memantine on the risk of falls, syncope, and related events, defined as fracture and accidental injury.

DESIGN

Meta-analysis of randomized controlled trials that were identified from MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (no language restriction, through July 2009), and manual search.

SETTING

Community and nursing homes.

PARTICIPANTS

Participants in fifty-four placebo-controlled randomized trials and extension studies of ChEIs and memantine that reported falls, syncope, and related events in cognitively impaired older adults.

MEASUREMENTS

Falls, syncope, fracture, and accidental injury.

RESULTS

ChEI use was associated with greater risk of syncope (odds ratio (OR)=1.53, 95% confidence interval (CI)=1.02-2.30) than placebo but not with other events (falls: OR=0.88, 95% CI=0.74-1.04; fracture: OR=1.39, 95% CI=0.75-2.56; accidental injury: OR=1.13, 95% CI=0.87-1.45). Memantine use was associated with fewer fractures (OR=0.21, 95% CI=0.05-0.85) but not with other events (falls: OR=0.92, 95% CI=0.72-1.18; syncope: OR=1.04, 95% CI=0.35-3.04; accidental injury: OR=0.80, 95% CI=0.56-1.12). There was no differential effect according to type and severity of cognitive impairment, residential status, or length of follow-up, although because of underreporting and small number of events, a potential benefit or risk cannot be excluded.

CONCLUSION

ChEIs may increase the risk of syncope, with no effects on falls, fracture, or accidental injury in cognitively impaired older adults. Memantine may have a favorable effect on fracture, with no effects on other events. More research is needed to confirm the reduction in fractures observed for memantine.

Understanding higher level gait disturbances in mild dementia in order to improve rehabilitation: 'last in-first out'

Predicting and anticipating disturbances in higher level gait is particularly relevant for patients with dementia as higher level gait appears to be closely related to higher level cognitive functioning. A phenomenon that could contribute to the understanding and prediction of disturbances in higher level gait and gait-related motor activity in the various subtypes of dementia is paraphrased as 'last in-first out'. 'Last in-first out' refers to the principle that neural circuits that mature late in development are the most vulnerable to neurodegeneration. The strength of relating symptoms to the 'last in-first out' principle is that a future symptom can be predicted and anticipated in a therapeutic way, even if the disease process has not already started. Therefore, the aim of this review is to provide new strategies for rehabilitation of higher level gait disturbances in dementia based upon the 'last in-first out' principle. These new strategies emerge from five neural networks: the superior longitudinal fasciculus, the uncinate fasciculus, the fronto-cerebellar and fronto-striatal connections, and the cingulum.

The Potential of Gait Analysis to Contribute to Differential Diagnosis of Early Stage Dementia: Current Research and Future Directions

Early differential diagnosis of dementia is becoming increasingly important as new pharmacologic therapies are developed, as these treatments are not equally effective for all types of dementia. Early detection and differential diagnosis also facilitates informed family decision making and timely access to appropriate services. Information about gait characteristics is informative in the diagnostic process and may have important implications for discriminating among dementia subtypes. The aim of this review paper is to summarize existing research examining the relationships between gait and dementia, including gait classification systems and assessment tools, gait patterns characteristic of different dementias (Alzheimer's disease, vascular dementia, dementia with Lewy Bodies, and fronto-temporal dementia), and the utility of gait analysis in early-stage diagnosis. The paper concludes with implications for future research.

Managing gait disorders in older persons residing in nursing homes: a review of literature

Managing gait disorders in the nursing home setting is a challenge. Nursing home residents can present with a variety of factors that may contribute to the presentation of gait abnormalities. The development of an individualized intervention program can be effective in improving a resident's ability to ambulate. This article reviews the research pertaining to the management of gait disorders including deconditioning, therapeutic exercise intervention, dementia, and cardiovascular and cardiopulmonary systems. The review provides the reader with strategies to help improve and understand gait performance in older persons residing in nursing homes.

Test-retest reliability and minimal detectable change scores for the timed "up & go" test, the six-minute walk test, and gait speed in people with Alzheimer disease

BACKGROUND

With the increasing incidence of Alzheimer disease (AD), determining the validity and reliability of outcome measures for people with this disease is necessary.

OBJECTIVE

The goals of this study were to assess test-retest reliability of data for the Timed "Up & Go" Test (TUG), the Six-Minute Walk Test (6MWT), and gait speed and to calculate minimal detectable change (MDC) scores for each outcome measure. Performance differences between groups with mild to moderate AD and moderately severe to severe AD (as determined by the Functional Assessment Staging [FAST] scale) were studied.

DESIGN

This was a prospective, nonexperimental, descriptive methodological study.

METHODS

Background data collected for 51 people with AD included: use of an assistive device, Mini-Mental Status Examination scores, and FAST scale scores. Each participant engaged in 2 test sessions, separated by a 30- to 60-minute rest period, which included 2 TUG trials, 1 6MWT trial, and 2 gait speed trials using a computerized gait assessment system. A specific cuing protocol was followed to achieve optimal performance during test sessions.

RESULTS

Test-retest reliability values for the TUG, the 6MWT, and gait speed were high for all participants together and for the mild to moderate AD and moderately severe to severe AD groups separately (intraclass correlation coefficients > or = .973); however, individual variability of performance also was high. Calculated MDC scores at the 90% confidence interval were: TUG=4.09 seconds, 6MWT=33.5 m (110 ft), and gait speed=9.4 cm/s. The 2 groups were significantly different in performance of clinical tests, with the participants who were more cognitively impaired being more physically and functionally impaired.

LIMITATIONS

A single researcher for data collection limited sample numbers and prohibited blinding to dementia level.

CONCLUSIONS

The TUG, the 6MWT, and gait speed are reliable outcome measures for use with people with AD, recognizing that individual variability of performance is high. Minimal detectable change scores at the 90% confidence interval can be used to assess change in performance over time and the impact of treatment.

The role of higher-level cognitive function in gait: executive dysfunction contributes to fall risk in Alzheimer's disease

Alzheimer's disease (AD) is generally understood as primarily affecting cognition while sparing motor function, at least until the later stages of the disease. Studies reported over the past 10 years, however, have documented a prevalence of falls in AD patients significantly higher than in age-matched normal elders; also persons with AD have been observed to have different walking patterns with characteristics that increase gait instability. Recent work in cognitive neuroscience has begun to demonstrate the necessity of intact cognition, particularly executive function, for competent motor control. We put the pieces of this puzzle together and review the current state of knowledge about gait and cognition in general along with an exploration of the association between dementia, gait impairment and falls in AD. We also briefly examine the current treatment of gait instability in AD, mainly exercise, and propose a new approach targeting cognition.

Quantitative gait analysis in patients with dementia with Lewy bodies and Alzheimer's disease

Gait disorders in people with dementia have been documented in a number of studies. There is some preliminary evidence suggesting there may be a relationship between dementia type and gait abnormality. Quantitative gait analysis has not previously been reported for people diagnosed with dementia with Lewy bodies (DLB). Therefore, this study aimed to quantify gait patterns of people with DLB and compare them with those of people with Alzheimer's disease (AD) and control subjects. Two groups of 10 subjects divided according to a diagnosis of DLB and AD, and 10 control subjects underwent gait analysis using an electronic walkway. Participants were required to walk at self-selected slow, preferred and fast speeds. There were no differences between the DLB and AD patient groups for any of the measured gait variables. Velocity and stride length values were significantly reduced in both patient groups compared to the control group at all speeds and percentage of time spent in double limb support was significantly increased in both patient groups compared to the control group at all walking speeds. Significant correlations were found between gait speeds and gait outcome variables. Spatiotemporal gait characteristics of people with AD and DLB are similar, but significantly different from the normal population.

Physical activity and cognition in Alzheimer's disease: relationship to vascular risk factors, executive functions and gait

Epidemiological studies show a positive relationship between physical activity and cognition in patients with Alzheimer's disease (AD). A relatively small number of intervention studies have examined the effects of physical activity, such as walking, on cognition in AD patients. The results of these studies, reviewed here, include both positive and negative findings. The finding that physical activity does not improve cognition in all AD patients could be explained by two factors that have received little attention thus far: executive dysfunction and gait disturbances. These two factors are part of a cascade of events, initiated by cerebrovascular disease in AD. This cascade of events is addressed in detail. Finally, (non)pharmacological interventions to improve executive dysfunctions and gait disturbances in patients with AD are discussed.

Prevention of falls in older people with dementia

Falls are a major cause of morbidity and mortality in older people with dementia. However, although we know that people with dementia can comply with interventions known to reduce falls in cognitively normal populations, and that these interventions can modify certain risk factors for falls in patients with dementia, direct evidence that falls can be prevented in older people with dementia is lacking. Further research is required specifically targeting fall prevention in older people with dementia.

Gait in ageing and associated dementias; its relationship with cognition

The focus of this review is on the close relationship between gait and cognition in ageing and associated dementias. This close relationship is supported by epidemiological studies, clinical studies of older people with and without dementia that focused on the intensity of the physical activity, clinical studies with older persons without dementia examining a relationship between gait and specific cognitive processes, and human and animal experimental studies examining a neural basis for such a relationship. Despite these findings, most studies with patients with dementia focus exclusively on the relationship between cognition and dementia, with relatively few addressing the relationship between gait and dementia. However, subtle disturbances in gait can be observed in ageing and in (preclinical) subtypes of dementia that are not known for prominent motor disturbances, i.e. Mild Cognitive Impairment, Alzheimer's Disease, vascular Cognitive Impairment No Dementia, Subcortical Ischaemic Vascular Dementia, Frontotemporal Mild Cognitive Impairment, and Frontotemporal Dementia, supporting a close relationship between gait and cognition. The relationship between gait and cognition is weakened by the few available intervention studies that examine the effects of walking on cognition in patients with (preclinical) dementia. These studies report equivocal results, which will be discussed. Finally, suggestions for future research will be made.

Timed Gait test: normative data for the assessment of the AIDS dementia complex

The Timed Gait test is a standardized procedure assessing motor dysfunction of lower extremities and gait abnormalities associated with AIDS dementia complex. Heretofore, interpretations of Timed Gait results have been hampered by the lack of normative data. We provide results on this test derived from 1,549 subjects (HIV-seronegatives (HIV-) and seropositives (HIV+) classified according to ADC stage). Timed Gait was found to be a useful screening and assessment tool for evaluating ADC and correlated with clinical ADC staging as well as more extensive structured neurological and neuropsychological evaluations. Analysis of covariance results (with age and education as covariates) revealed symptomatic HIV+(SX) and AIDS groups having significantly slower Timed Gait scores than those in the HIV- and asymptomatic HIV+(ASX) groups. The SX group obtained significantly slower timed gait scores than those in the AIDS group. There was a significant increase in Timed Gait scores with each increase in dementia staging with the HIV- subjects having the fastest mean Timed Gait scores and the HIV+ dementia stage 2+ having the slowest. These normative data should prove useful in both recognition of ADC and treatment response. Given its minimal training requirements, the Timed Gait would have utility in resource limited settings.

Lower gait speed in older women with dementia compared with controls

Movement time is increased in patients with Alzheimer's disease.

OBJECTIVES

To study differences in movement time and ability to increase speed in older women with dementia.

METHODS

Four tests were performed at self-selected and maximal speed: walking 2 x 15 m, walking between parallel lines, 'get up and go' (GUG) and rising from lying supine. Twenty-two patients and 22 controls (mean ages 81 and 86 years, respectively) were included in the study.

RESULTS

In the groups over 80 years, walking and GUG at both speeds and rising from lying supine from the left at self-selected speed were significantly slower among patients (20-30%). Both patients and controls were able to increase movement speed when changing from self-selected to maximal speed (13-27%). Patients with Alzheimer's disease had lower self-selected walking speed compared with patients with other types of dementia (p = 0.048).

CONCLUSION

Testing physical performance in two different speeds was feasible in patients with dementia. Patients had slower gait speed and were slower in the functional tests, such as GUG, but the capacity to increase speed seemed intact.

Correlation of midbrain diameter and gait disturbance in patients with idiopathic normal pressure hydrocephalus

BACKGROUND AND PURPOSE

Although gait disturbance is an important feature of idiopathic normal pressure hydrocephalus (NPH), only tentative theories have been offered to explain its pathophysiology. It has been suggested that the mesencephalic locomotor region is the anatomical substrate for the development of the hypokinetic NPH gait. To investigate this possibility, we evaluated the correlation between gait disturbance and midbrain diameter.

METHODS

We enrolled 21 patients with NPH and 20 age-matched control subjects for the study. The maximal diameter of the midbrain and pons, and the width of the lateral and third ventricles were measured using midsagittal T1-weighted MRI and axial T2-weighted MRI, respectively. Gait disturbance, cognitive dysfunction, and incontinence were semiquantified.

RESULTS

The maximal midbrain diameter was significantly smaller in the NPH group than in the controls (14.8 +/- 0.9 vs. 17.1 +/- 0.7 mm, p < 0.001). There were inverse correlations between the midbrain diameter and the widths of the two ventricles (r = -0.562, p = 0.008 for the third ventricle, and r = -0.510, p = 0.018 for the lateral ventricle). The severity of gait disturbance was negatively correlated with the midbrain diameter (r = -0.598, p = 0.004), but the degree of cognitive dysfunction and incontinence showed no significant correlation with midbrain diameter or ventricular width.

CONCLUSIONS

This study suggests that midbrain atrophy is significantly associated with gait disturbance in NPH.

Falls in cognitive impairment and dementia

Older people with cognitive impairment and dementia are at increased risk for falls and subsequent adverse events. The most common risk factors for falls that are found specifically in patients with cognitive impairment and dementia are postural instability, medication, neurocardiovascular instability (particularly orthostatic hypotension), and environmental hazards. Based on data from studies in cognitively normal people who fall, modification of these risk factors may prevent falls in older people with cognitive impairment and dementia. Preliminary research in subjects with cognitive impairment and dementia suggests that physiotherapy may have a role in falls prevention. Additionally, risk-factor-targeted interventions may reduce the risk of falls in patients who have cardiovascular abnormalities and neurocardiovascular instability.

Non-neurological factors are implicated in impairments in gait and mobility among patients in a clinical dementia referral population

Although gait abnormalities have been previously noted in dementia, their non-neurological correlates have not been examined. We used data on 900 consecutive outpatients assessed from 1994 to 1999 in the University of Nebraska Geriatric Assessment Clinic Data Base (UN-GAC) to examine the prevalence of gait disorders and the relationship of gait disorders to physical illness in Alzheimer's disease (AD) and non-AD dementia. Gait disorders were very prevalent at each level of cognitive function [58.7% for CDR=0, 68.0% for CDR=0.5, 57.9% for CDR=1, 68.1% for CDR=2 and 76.9% for CDR=3, p=0.02] and were more frequently observed in AD patients with poorer cognitive function. Among all demented patients, 45.0% of those without gait impairment were ADL independent compared to 11.8% of those with gait impairment. In adjusted logistic regression models, the presence of a gait disorder among AD patients was significantly associated with older age (Odds Ratio (OR)=1.09, 95% Confidence Intervals (CI)=1.04-1.15), special sensory (2.19, 1.17-4.12), and lower GI (3.57, 1.97-6.47) dysfunction. The prevalence of gait disorders is high in even mildly demented persons and associated with common and often treatable organ system dysfunction. Because gait disorders are also associated with a high prevalence of ambulatory disability, attention to co morbid illnesses implicated in gait impairment may reduce the burden of disability in this population.

Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson's disease

OBJECTIVES

Comparative gait analyses in neurological diseases interfering with locomotion are of particular interest, as many hypokinetic gait disorders have the same main features. The aim of the present study was (1) to compare the gait disturbance in normal pressure hydrocephalus and Parkinson's disease; (2) to evaluate which variables of the disturbed gait pattern respond to specific treatment in both diseases; and (3) to assess the responsiveness to visual and acoustic cues for gait improvement.

METHODS

In study 1 gait analysis was carried out on 11 patients with normal pressure hydrocephalus, 10 patients with Parkinson's disease, and 12 age matched healthy control subjects, on a walkway and on a treadmill. In study 2, patients with normal pressure hydrocephalus were reinvestigated after removal of 30 ml CSF, and patients with Parkinson's disease after administration of 150 mg levodopa. In part 3 visual cues were provided as stripes fixed on the walkway and acoustic cues as beats of a metronome.

RESULTS

The gait disorder in both diseases shared the feature of a reduced gait velocity, due to a diminished and highly variable stride length. Specific features of the gait disturbance in normal pressure hydrocephalus were a broad based gait pattern with outward rotated feet and a diminished height of the steps. After treatment in both diseases, the speed increased, due to an enlarged stride length, now presenting a lower variability. All other gait variables remained unaffected. External cues only mildly improved gait in normal pressure hydrocephalus, whereas they were highly effective in raising the stride length and cadence in Parkinson's disease.

CONCLUSION

The gait pattern in normal pressure hydrocephalus is clearly distinguishable from the gait of Parkinson's disease. As well as the basal ganglia output connections, other pathways and structures most likely in the frontal lobes are responsible for the gait pattern and especially the disturbed dynamic equilibrium in normal pressure hydrocephalus. Hypokinesia and its responsiveness to external cues in both diseases are assumed to be an expression of a disturbed motor planning.

Motor function and disability in the dementias

Epidemiological and neuropathological series have identified three predominant dementing processes; Alzheimer's disease (AD), vascular dementia (VaD) and dementia associated with Lewy bodies (termed Parkinson's disease dementia (PDD) in this paper). While each has its own distinguishing features and by definition all impact upon day to day functioning, no random community derived sample has examined clinical features as defined by gait and balance abnormalities and compared disability ratings of the three dementias simultaneously. Six hundred and forty-seven community dwelling subjects participated in the Sydney Older Persons Study and of these 537 participated in a medical assessment. Of these 537,482 informants rated disability. Gait and balance abnormalities of the three major dementias were identified and the association of the dementias with disability examined. The three major dementias showed evidence of both slowing and ataxia in gait and balance tests. This was maximal in those with PDD. Similarly, all showed evidence of disability that was maximal in those with PDD. In conclusion, this study has identified that gait abnormalities are present in all three dementias to a varying degree. It is hypothesised that the varying levels of disability observed are a consequence of the varying levels of motor impairment, resulting in greater levels of disability in those with PDD.