Visual perception dominance of fallers among community-dwelling older adults

Fear of falling: Scoping review and topic analysis using natural language processing

Fear of falling (FoF) is a major concern among older adults and is associated with negative outcomes, such as decreased quality of life and increased risk of falls. Despite several systematic reviews conducted on various specific domains of FoF and its related interventions, the research area has only been minimally covered by scoping reviews, and a comprehensive scoping review mapping the range and scope of the research area is still lacking. This review aims to provide such a comprehensive investigation of the existing literature and identify main topics, gaps in the literature, and potential opportunities for bridging different strains of research. Using the PRISMA-ScR guidelines, we searched the Cochrane Database of Systematic Reviews, CINAHL, Embase, MEDLINE, PsycInfo, Scopus, and Web of Science databases. Following the screening process, 969 titles and abstracts were chosen for the review. Pre-processing steps included stop word removal, stemming, and term frequency-inverse document frequency vectorization. Using the Non-negative Matrix Factorization algorithm, we identified seven main topics and created a conceptual mapping of FoF research. The analysis also revealed that most studies focused on physical health-related factors, particularly balance and gait, with less attention paid to cognitive, psychological, social, and environmental factors. Moreover, more research could be done on demographic factors beyond gender and age with an interdisciplinary collaboration with social sciences. The review highlights the need for more nuanced and comprehensive understanding of FoF and calls for more research on less studied areas.

Fear of falling: scoping review and topic analysis protocol

INTRODUCTION

Fear of falling (FoF) is a major challenge for the quality of life among older adults. Despite extensive work in previous scoping and systematic reviews on separate domains of FoF and interventions related to FoF, very little attention has been devoted to a comprehensive scoping review mapping the range and scope of this burgeoning area of study, with only a few exceptions. This scoping review aims to provide an overarching review mapping FoF research by identifying main topics, gaps in the literature and potential opportunities for bridging different strains of research on FoF. Such a comprehensive scoping review will allow the subsequent creation of an interdisciplinary theoretical and empirical framework, which may help push forward policy and practice innovations for people living with FoF.

METHODS AND ANALYSIS

Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews (PRISMA-ScR), seven main databases will be searched from 2000 to the date of the start of the review: Cochrane Database of Systematic Reviews, CINAHL, Embase, MEDLINE, PsycInfo, Scopus and Web of Science. The review will include original research in English, published between 2000 and January 2023. Quality checks will be conducted collegially. Data will be extracted and analysed using PRISMA-ScR charting tools and conventions.

ETHICS AND DISSEMINATION

No ethics approval is required for the review. The results will be submitted to a peer-reviewed journal and presented at academic conferences. The outcomes will be disseminated through social media, opinion pieces and science communication platforms to reach a wider audience.

REGISTRATION

The scoping review was registered with the Open Science Framework (https://osf.io/gyzjq).

Measuring Vestibular Contributions to Age-Related Balance Impairment: A Review

Aging is associated with progressive declines in both the vestibular and human balance systems. While vestibular lesions certainly contribute to imbalance, the specific contributions of age-related vestibular declines to age-related balance impairment is poorly understood. This gap in knowledge results from the absence of a standardized method for measuring age-related changes to the vestibular balance pathways. The purpose of this manuscript is to provide an overview of the existing body of literature as it pertains to the methods currently used to infer vestibular contributions to age-related imbalance.

Sensory reweighting in frail aged adults: Are the balance deficiencies mainly compensated by visual or podal dependences?

BACKGROUND

Postural control is based on the integration of different sensory inputs. The process of scaling the relative importance of these sensory cues (visual, vestibular and proprioceptive) depends on individuals and creates sensory preferences, leading to sensory dependences when one particular source is preponderant. In this context, the literature showed a frequent visual dependence (visual inputs weighting) in aged adults. However, the somaesthetic inputs can also be prioritised in a podal-dependent profile. In the frail aged adults, none study has shown the distribution of these two dependences.

RESEARCH QUESTION

Which sensory orientation profile is preferentially adopted by frail aged males and females?

METHODS

In this cross-sectional study, we compared 33 frail aged adults to 16 non frail aged adults during a static postural control task in three conditions on a force platform: i) a standard condition, ii) a no-vision condition and iii) a foam condition. An analysis with the factor sex was also performed in each group of participants.

RESULTS

The analysis of stabilometric parameters (mean velocity and mean velocity variance) highlighted a significant difference in no-vision or foam conditions when compared to the standard condition in frail aged males and only in the foam condition when compared to the standard condition for females in the frail group. No significant difference was observed between conditions in the control group.

SIGNIFICANCE

Our study showed the predominance of both visual and podal information in frail aged adults when controlling their posture. Considering the sex factor, frail males were more dependents to their visual cues than frail females. This result should be used when designing the rehabilitation programs in this population.

The Postural Control Indexes during Unipodal Support in Patients with Idiopathic Scoliosis

Proper posture provides the best balance and body stability at minimal muscular effort. It is constantly controlled by the central nervous system, which integrates the stimuli from the proprioceptors (deep feeling sensors), vision receptors, and balance receptors through the subcortical structures. The main purpose of the study was to describe single stance stability and its correlation with the degree of scoliosis and trunk rotation among patients suffering from idiopathic scoliosis and in the control group without scoliosis. The study included 80 patients (69 girls and 11 boys) and 40 healthy children without scoliosis (21 girls and 19 boys). The Cobb angle technique was used to determine the magnitude of the deformity. All subjects were divided into three subgroups according to Bogdanov's classification. Single stance stability with eyes open and eyes closed was assessed with an electronic postural station-Delos Postural Proprioceptive System (DPPS). In case of multiple group comparisons for variables with normal distribution ANOVA with Scheffe, post hoc test was used or Kruskal-Wallis test was used as the nonparametric equivalent. The relationship between the two continuous variables was investigated using either Pearson product-moment correlation or Spearman's rank correlation. In all these calculations, the statistical significance level was set to p < 0.05. The single stance test showed a significant difference between the stability index with eyes open and stability index with eyes closed in study and control groups. The character of these alterations is influenced by the degree of trunk rotation. The degree of scoliosis according to Bogdanov classification does not determine the decrease in stability indexes. In summary, significantly lower values of the stability index during one-leg standing with eyes closed indicated balance impairment, which is mainly connected with inadequate functioning of the proprioceptive system.

Plantar cutaneous afferents influence the perception of Subjective Visual Vertical in quiet stance

The estimation of Subjective Visual Vertical (SVV) involves the allocentric, gravitational and egocentric references, which are built by visual, vestibular and somatosensory afferents. Our goals were to assess the influence of plantar cutaneous afferents on the perception of SVV, and to see if there is a difference according to the efficiency of plantar cutaneous afferents. We recruited 48 young and healthy subjects and assessed their SVV and postural performances in quiet stance with a force platform, at 40 or 200 cm, in four ground conditions: on firm ground, on foam, with a bilateral, or with a unilateral 3 mm arch support. We also assessed the efficiency of our subjects' plantar afferents with the plantar quotient method and divided them in two groups: subjects with a normal use of plantar afferents and subjects with Plantar Exteroceptive Inefficiency (PEI). The results showed significant decreases in the counter clockwise SVV deviation only with the unilateral arch support, at near distance, and among the typically behaving subjects. We conclude that asymmetric foot cutaneous afferents are able to bias the egocentric vertical reference and hence influence the perception of SVV. This influence disappears among subjects with PEI, probably because of a distortion of the plantar signal.

Fear of falling and postural reactivity in patients with glaucoma

Purpose

To investigate the relationship between postural metrics obtained by dynamic visual stimulation in a virtual reality environment and the presence of fear of falling in glaucoma patients.

Methods

This cross-sectional study included 35 glaucoma patients and 26 controls that underwent evaluation of postural balance by a force platform during presentation of static and dynamic visual stimuli with head-mounted goggles (Oculus Rift). In dynamic condition, a peripheral translational stimulus was used to induce vection and assess postural reactivity. Standard deviations of torque moments (SDTM) were calculated as indicative of postural stability. Fear of falling was assessed by a standardized questionnaire. The relationship between a summary score of fear of falling and postural metrics was investigated using linear regression models, adjusting for potentially confounding factors.

Results

Subjects with glaucoma reported greater fear of falling compared to controls (-0.21 vs. 0.27; P = 0.039). In glaucoma patients, postural metrics during dynamic visual stimulus were more associated with fear of falling (R² = 18.8%; P = 0.001) than static (R² = 3.0%; P = 0.005) and dark field (R² = 5.7%; P = 0.007) conditions. In the univariable model, fear of falling was not significantly associated with binocular standard perimetry mean sensitivity (P = 0.855). In the multivariable model, each 1 Nm larger SDTM in anteroposterior direction during dynamic stimulus was associated with a worsening of 0.42 units in the fear of falling questionnaire score (P = 0.001).

Conclusion

In glaucoma patients, postural reactivity to a dynamic visual stimulus using a virtual reality environment was more strongly associated with fear of falling than visual field testing and traditional balance assessment.

Visual Acuity, Visual Disabilities and Falling in the Elderly

Poor vision has been suggested as a risk factor for falling in the elderly. We analyzed the findings from a cohort of community-dwelling elderly (N = 875) to determine the relative risks for impaired visual acuity and various visual disabilities with falling, recurrent falling, and serious injurious falls. The prevalences of impaired visual acuity and four visual disabilities were low. None of the vision variables examined predicted time to first serious injurious fall after controlling for balance, cognition, age, and gender. However, bumping into objects predicted falling and recurrent falling. The lack of associations between visual disabilities and falling suggests that poor vision, as measured here, plays a limited role in predicting falling in relatively well community-dwelling elderly.

Single stance stability and proprioceptive control in older adults living at home: gender and age differences

In developed countries, falls in older people represent a rising problem. As effective prevention should start before the risk becomes evident, an early predictor is needed. Single stance instability would appear as a major risk factor. Aims of the study were to describe single stance stability, its sensory components, and their correlation with age and gender. A random sample of 597 older adults (319 men, 278 women) living at home, aged 65–84, was studied. Stability tests were performed with an electronic postural station. The single stance test showed the impairment of single stance stability in older individuals (75–84 yrs). The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses. Younger subjects (65–74 yrs) exhibited better, but still inadequate, proprioceptive control with compensatory visual stabilization. Gender differences appeared in older subjects: women were significantly less stable than men. The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident. Adequate proprioceptive control could mitigate the effects of all other risks of falling.

Ocular dominance and balance performance in healthy adults

PURPOSE

To evaluate the effect of ocular dominance on balance performance in healthy adult subjects.

METHODS

Ocular dominance was determined in 24 healthy subjects using the hole-in-the-paper test. Balance function was evaluated by computerized dynamic platform posturography (CDPP). Sway index (SI), antero-posterior sway (APS) and lateral sway (LS) were served as outcome parameters.

RESULTS

The outcome parameters did not differ significantly between dominant and non-dominant eye fixation both in static and angular balance tests (SI-5.47+/-0.42, 6.23+/-0.52, p=0.146 and 18.4+/-1.07, 19.11+/-1.15, p=0.142, respectively; APS--2.26+/-4.68, -5.1+/-4.6, p=0.082 and -1.94+/-3.33, -3.64+/-2.6, p=0.48, respectively; LS--1.21+/-1.46, -1.12+/-1.66 p=0.94 and -1.98+/-1.16, -1.55+/-1.39, p=0.69, respectively).

CONCLUSIONS

Ocular dominance does not seem to affect postural function in the monovision and far viewing condition.

Age-differences in the free vertical moment during step descent

BACKGROUND

This study utilises a rarely examined biomechanical parameter--the free vertical moment--to determine age-related differences in rotational kinetics of the body about the vertical-axis when stepping down from a stationary position.

METHODS

Ten older and 10 young adults completed step-downs from three heights. Free vertical moment impulse and peak during step-initiation double-support and the subsequent step-execution phase, and vertical-axis pelvis angular displacement and velocity at instant of landing were compared.

FINDINGS

The free vertical moment during double-support was directed away from the intended lead-limb side, producing a change in vertical-axis rotational momentum that moved the lead-limb in a forwards-medial direction about the stationary support/trailing limb during the subsequent step-execution phase. The free vertical moment during step-execution was directed towards the lead-limb side and acted to slow/halt the body's vertical-axis rotation away from lead-limb side. Free vertical moment impulse and peak during double-support were similar between groups (P>0.05), but during step-execution were significantly reduced in older adults (P=0.002). As a result older adults had greater vertical-axis pelvis angular displacement and velocity at instant of landing (directed away from lead-limb side), with significant (P<0.001) group-by-step height interactions indicating that differences between groups became more pronounced with increasing step-height.

INTERPRETATION

These findings highlight that older adults were unable to exert the same vertical-axis control during single-support as young subjects did. Findings also highlight that the analysis of free vertical moment data can be a useful biomechanical tool to highlight age-related differences in how steps/stairs are negotiated.

Detection of baseline and near-fall postural stability

It is unknown whether there are any measurable warning signs just before a patient falls. This study of postural position just prior to a fall involved a subject standing on a balance beam while wearing a gyroscope-based wireless data acquisition system. Results show a variation in postural position when the subject appeared stable. This occurred well before the subject experienced a fall and could not be classified as pre-fall or fall. The results show that there are two distinguishable levels of postural stability - baseline and near-fall.

Is backward disequilibrium in the elderly caused by an abnormal perception of verticality? A pilot study

OBJECTIVE

We hypothesised that backward disequilibrium (BD), defined by a posterior position of the centre of mass with respect to the base of support, could be caused by a backward tilt in the perception of verticality.

METHODS

The relationship between BD, the perception of verticality, and the history of falls in 25 subjects aged 84.5+/-7.4 years was analysed. An original ordinal scale, the BD scale (BDS), was used to quantify BD. Postural (PV) and haptic verticals (HV) were measured in sagittal plane.

RESULTS

BDS scores closely correlated with the number of falls (r = 0.81, p =10(-5)). The more the PV was tilted backward, the greater the BDS scores (r = -0.95, p<10(-6)), with a huge backward tilt of about 15 degrees in 4 subjects with severe BD. In these subjects, the tilt in perception of verticality was transmodal since a severe backward HV tilt was also found.

CONCLUSIONS

This transmodality suggested high-order cognitive disruption in the construction of the subjective vertical used in postural control by subjects showing BD, which confirmed our hypothesis.

SIGNIFICANCE

This study clearly shows that perception and action with respect to gravity are closely related and brings a new insight about fall mechanisms in the elderly.

Postural visual dependence after recent stroke: assessment by optokinetic stimulation

INTRODUCTION

This study was conducted to assess visual dependence of postural control early after stroke.

DESIGN

Case control study.

SETTING

A Physical Medicine and Rehabilitation Department.

METHOD

Twenty-five patients impaired by severe hemiplegia due to a recent first stroke, were examined. Fourteen had a right and 11 a left hemispheric lesion. There were aged 52+/-13 years, time since stroke was 30+/-12 days. Patients' data were compared to data for 25 healthy subjects. Sitting posture was assessed on a dynamic balance, using two parameters: frontal plane displacement of the centre of pressure under optokinetic stimulation (OKS), and the total length of centre of pressure displacement for the stability reaction. On the basis of 90th percentile control data, patients' behaviour was classified as totally visuo independent (VI), totally visuo dependent (VD) or mixed.

RESULTS

Body tilt under OKS was greater in patients than controls. No control subject was totally VD, 19 subjects were totally VI. Four patients were totally VD and only six were VI. The only clinical parameter linked to the effect of OKS was the sensitivity impairment. Overall patients with visuospatial neglect were the most perturbed, but two were totally visuo independent.

DISCUSSION AND CONCLUSION

Assessment of postural variations in sitting under OKS is proposed for estimating visual dependence early after stroke. Individual reactions are more important than mean group reactions. Visual dependence is not solely due to neurological impairment, implying that previous physiological behaviour may be involved. Knowledge of these characteristics may affect rehabilitation programmes.

[Visual dependence after recent stroke]

INTRODUCTION

After chronic stroke, inability to use pertinent somatosensory or vestibular information have been described. The aim of the study was to determine whether visual dependence occurred early after stroke before rehabilitation.

METHOD

Thirty patients with recent hemiplegia (16 right and 14 left hemispheric stroke) performed the rod and frame test (RFT). Patients were asked to adjust the rod to the vertical position under 3 conditions: basically, with a frame tilted 18 degrees to the right and then with the frame tilted to the left. Bias in each condition (mean, SD) was recorded and compared to adjustments of the rod by 23 controls. Motor control, sensibility, functional level (functional independence measure), age, neglect, and then balance by the postural assessment scale for stroke were assessed.

RESULTS

Fifty-six per cent (17/30) of patients but only 26% of controls were influenced by the tilt of the frame on the 2 sides (visual dependence). No correlation was found between visual dependence and the characteristics of the patients.

DISCUSSION

Many patients with recent hemiplegia seem to rely on visual input. The mechanisms of such visual dependence are discussed. Rehabilitation programs should take into account the possible impairment of sensory organisation and should include exercises to be performed under visual disturbances.

Prevention of falls in older people

In recent years the evidence base for prevention of falls in older people has increased and associated with this has been an inevitable expansion in clinical services which attempt to localize and implement what is described in the literature. This article reviews the basic physiology implicit in maintenance of the upright posture; highlights the diversity of medical and non-medical risk factors associated with falls; describes the clinical assessment of an older person at risk of falls; reviews the evidence for intervention in the prevention of falls in older people; and acknowledges the need for a clear strategic direction to successfully prevent falls and the requirement for ongoing research as well as much needed service evaluation.

Effects of age related sensory degradation on perception of floor slipperiness and associated slip parameters

A laboratory study was conducted to determine how sensory changes in elderly people affect subjective assessments of floor slipperiness, and associated friction demand characteristics and slip distance. To relate these parameters to actual slip and fall incidents, 30 subjects from two age groups (young and elderly) walked around a circular track on the slippery and non-slippery floor surfaces, while wearing a safety harness to prevent injury in case of a slip or fall. Prior to the walking experiment, the Sensory Organization Test was performed. During the experiment, subjective assessments of surface slipperiness of the floor were obtained prior to walking and after walking on the floor. Slip distance, required coefficient of friction (RCOF) and adjusted friction utilization (AFU) were assessed utilizing motion analysis and force platform systems. The results indicated that sensory changes in the elderly increased the likelihood of slips and falls more than their younger counterparts. This was due to incorrect perceptions of floor slipperiness, and uncompensated slip parameters such as slip distance and adjusted friction utilization.

Exercise in the prevention of falls in older people: a systematic literature review examining the rationale and the evidence

Falls are a major source of death and injury in elderly people. For example, they cause 90% of hip fractures and the current cost of hip fractures in the US is estimated to be about 10 billion dollars. Age-related changes in the physiological systems (somatosensory, vestibular and visual) which contribute to the maintenance of balance are well documented in older adults. These changes coupled with age-related changes in muscle and bone are likely to contribute to an increased risk of falls in this population. The integrated rehabilitation-based model of fall risk factors reveals multiple sites for interventions that may reverse fall risk factors. Regular exercise may be one way of preventing falls and fall-related fractures. The evidence for this contention comes from a variety of sources. On the basis of 9 randomised controlled studies conducted since 1996, exercise appears to be a useful tool in fall prevention in older adults, significantly reducing the incidence of falls compared with control groups. However, current limitations such as inconsistencies in the measurement of key dependent and independent variables do not, at present, permit a meta-analysis of intervention trials. Further investigation, using trials designed with the current limitations in mind, is necessary to establish the optimum exercise programme to maximise fall prevention in older adults.

Age related effects of transitional floor surfaces and obstruction of view on gait characteristics related to slips and falls

A laboratory study was conducted to examine gait changes between younger and older subjects as they walked across different floor surfaces. Twenty subjects participated in the experiment (five each of older and younger males and females). For half of the trials, subjects carried light loads that blocked their view of the floor surface immediately in front of them. Subjects walked on slippery (soapy water on vinyl) and stable (outdoor carpet) floor surfaces, as well as transitioning from one surface to another. Responses studied included: required coefficient of friction (RCOF), stride length (SL), and minimum toe clearance (MTC). Significant effects were found for the floor surface, load versus no load condition, and some interactions involving age (older versus younger subjects). Not all expected differences due to age were found in this experiment. The lack of significant differences between younger and older subjects could be due to the older subjects that participated in the experiment. They were volunteers at a local medical center, were in good physical shape, and were probably not typical of the population of people over 65 years of age. RELEVANCE TO INDUSTRY: Slips and falls in industry are costly safety issues in terms of human suffering as well as financial compensation. In many facilities and at home, people make transitions from one floor surface to another many times each day, while carrying loads or just walking. A better understanding of characteristics of people as they walk on slippery floor surfaces and the changes that might occur with age, will allow engineers to design better floor surfaces to reduce the incidence of slips and falls.

Systemic effects of topical ophthalmic beta-adrenoceptor antagonists

Topical ophthalmic beta-adrenoceptor antagonists (beta-blockers) are generally recognized as the treatment of choice in glaucoma management due to favourable efficacy, safety and tolerability. Despite topical ocular administration, beta-blockers are systemically absorbed, in relatively small amounts, through the nasolacrimal drainage system and can adversely affect cardiovascular and pulmonary function. While cardioselective beta-blockers, such as betaxolol, possibly confer an advantage with respect to clinical safety through their receptor affinity, systemic effects are also influenced by other pharmacological factors, including the rate and extent of systemic absorption and the extent of plasma protein binding. These factors are reviewed to distinguish the various ophthalmic beta-blockers and to explain the observed clinical differences in the safety profiles of these medications.

Visual impairment and falls in older adults: the Blue Mountains Eye Study

OBJECTIVES

To examine the association between visual impairment and falls in older people.

DESIGN

Cross-sectional survey of eye disease with retrospective collection of falls data.

SETTING

Two postcode areas in the Blue Mountains west of Sydney, Australia.

PARTICIPANTS

All people 49 years of age and older were invited to participate, 3654 (82.4%) of 4433 eligible residents took part, and 3299 answered questions about falls.

MEASUREMENTS

Subjects had a detailed eye examination and answered questions about health and vision status, use of medication, and number of falls in the previous 12 months.

RESULTS

Tests of visual function that had a statistically significant association with two or more falls after adjustment for confounders were visual acuity (prevalence ratio (PR) 1.9 for visual acuity worse than 20/30), contrast sensitivity (PR 1.2 for a 1-unit decrease at 6 cycles per degree), and suprathreshold visual field screening (PR 1.5 for 5 or more points missing). However, only visual acuity and contrast sensitivity were significantly associated with two or more falls per 1 standard deviation decrease. The presence of posterior subcapsular cataract (PR 2.1) and use of nonmiotic glaucoma medication (PR 2.0) had a statistically significant association with two or more falls; presence of age-related macular degeneration, diabetic retinopathy, and cortical or nuclear cataract did not.

CONCLUSION

Visual impairment is strongly associated with two or more falls in older adults. In addition to poor visual acuity, visual factors such as reduced visual field, impaired contrast sensitivity, and the presence of cataract may explain this association.

Prevention of falls in the elderly

The purpose of these symposium presentations was to examine the role of physical activity as a means of preventing hip fractures through the prevention of falls. Risk factor identification is necessary to develop preventive strategies. Risk factors related to physical activity and other risk factors for falls were identified. Intervention studies aimed at reducing, preventing or delaying falls were identified and discussed. A literature search from 1976-1994, identified 52 studies examining risk factors for falls, recurrent falls and/or falls resulting in injury. Nine intervention studies were identified with the primary outcome of falls. Physical activity-related risk factors for falls include limitations in general functioning, such as ambulation and mobility problems, difficulty or dependence in activities of daily living, and exposures to the risks of falling as indicated by the nature and frequency of daily activities. Impairments in gait and balance as well as neuromuscular and musculoskeletal impairments frequently underlie changes in physical activity in old age. Reduced activity level may occur as a result of these impairments, leading to further declines in physical functioning and an increased risk of falls. A relatively high level of activity in old age is also associated with risk of falls. Other risk factors for falls, such as cognitive impairment, visual deficits and medication use, may combine with physical activity-related risk factors to increase the risk of falls. Intervention studies directed at nursing home populations did not prevent falls but had other statistically and clinically significant outcomes. Studies among the community dwelling that targeted potential or current risk factors and included an exercise component reported a significant reduction in falls, prevented the onset of new disabilities and reduced baseline risk factors. Prevention of falls and subsequent injuries in the institutionalized population remains a challenge. Further development of interventions for community-dwelling elders that facilitate maintenance of physical activity without unduly increasing the risk of falls is also critical. The potential for maintenance of benefits gained from all fall interventions needs further examination.

Age at onset: the major determinant of outcome in Parkinson's disease

Factors at presentation which influenced the course of the disease and response to treatment were assessed in 125 de novo patients with Parkinson's disease. Ninety-eight patients were available for re-assessment at 5 years. Older patients presented earlier after the onset of symptoms, deteriorated more rapidly, and were significantly more likely to develop dementia and impairment of balance. Increasing age and symmetrical disease predicted the new appearance of imbalance. Age of onset did not predict dyskinesia or end of dose failure. A low tremor score at baseline and female gender were predictive of the early appearance of dyskinesia. Patients who experienced end of dose failure were taking a significantly higher dose of levodopa. Once dose and duration of treatment were corrected for, no baseline features were predictive of end of dose failure. The dose of levodopa at 5 years was positively correlated to baseline disease severity as measured by the Columbia score. We conclude that the age of onset of symptoms of Parkinson's disease is a major determinant of the course of the disease and response to treatment.

Water-level representation by men and women as a function of rod-and-frame test proficiency and visual and postural information

In the water-level task, it has been repeatedly shown that, compared with men, women more often fail to represent the surface of a liquid as horizontal regardless of the tilt of the container. An attempt was made to reduce this robust gender gap through the manipulation of relevant upright references conveyed both by the position of the stimuli and the posture of the subject. It was reasoned that bringing the women to focus on such gravitational references through postural adjustment might help their performance equal that of men, thus shedding some light on the nature of the difficulty they experience in the standard setting. A lesser effect was anticipated among men. However, the results showed that, even after controlling for proficiency in the correlated visuospatial situation of the rod-and-frame test, the performance of men always surpassed that of women. Irrespective of gender, water-level representation on vertical sheets was unaffected by the subject's posture, whereas it improved when horizontal sheets were coupled with the most unstable posture. Whereas the persistence of the yet-unaccounted-for gender difference was underscored, the contributions of visual and postural cues issued at arm and full-body levels were discussed.

Visual field dependence in elderly fallers and non-fallers

Two tests of visual field dependence (a measure of reliance upon the spatial framework provided by vision in the perception of the upright)--roll vection and the rod and frame test--were administered to 136 participants aged fifty-nine to ninety-seven years. It was found that the fifty-nine participants who had experienced one or more falls in the past year were significantly more visually field dependent in both tests compared with the seventy-seven participants who had not fallen. Mean error in perception of the true vertical in the rod and frame test was 20.7 degrees for the fallers and 17.2 degrees for the non-fallers. Mean error in perception of the true vertical in the roll vection test was 6.6 degrees for the fallers and 3.6 degrees for the non-fallers. The test of roll vection was the better discriminator between fallers and non-fallers, which may be due in part to less misunderstanding of the required task by the participant. The results suggest that tilted or rolling visual stimuli may be factors leading to postural instability and falls in the elderly. The findings support the claim that greater dependence on visual information shown by fallers may be the result of reduced proprioceptive and vestibular function resulting from increased age and chronic health problems.

Perception and representation of the Euclidean coordinates in mature and elderly men and women

Research on gender differences in visuo-spatial tasks has been mostly limited to samples of preadolescents, adolescents, and young adults. In a life span perspective, the present study attempted to complete the available information by submitting mature and elderly men and women to three tasks involving the Euclidean spatial system. Aged 40 to 61, 62 to 72, and 73 to 84, and maximally equivalent across age and sex groups, the subjects performed the Rod-and-Frame Test, the water-level task, and a plumb-line task. Proficiency was expected to decrease with age and to be higher among men. It was found that, whatever their age, men surpassed women in the water-level and plumb-line tasks, whereas no gender difference was obtained on the Rod-and-Frame Test. Irrespective of sex, the oldest subjects were outperformed by the youngest on the Rod-and-Frame Test, while water-level and plumb-line achievement was independent of age. Depression and anxiety scores were not correlated with visuo-spatial performance. Discussion focused on the fact that the present highly homogeneous and selective sample allowed for the valid emergency of a distinctive pattern of gender and age contributions to the use of appropriate vertical and horizontal references once maturity is reached.

Falls

Falls are a health hazard for the elderly patient. Annually, approximately 30 per cent or more of elderly patients will experience such a problem. Seventy per cent of deaths from falls occur in the elderly population. Morbidity from falls includes fractures, soft tissue trauma, anxiety about further falls, and loss of confidence. Falls are due to environmental factors; neurologic illness including dementia, drop attacks, and sensory loss; alcohol and drug use; orthostatis; cardiac arrhythmias; and acute illnesses such as infection, heart failure, and gastrointestinal bleeding. The physician who treats elderly patients needs to identify those patients at risk or those who already have the problem. Evaluation should not be limited to assessment for injury and must include establishing an etiology. Therapy depends upon determining the precise etiology for the fall and rectifying contributing factors.

Impaired vision and hip fracture. The Framingham Study

Falls affect a large proportion of the elderly and can result in a variety of injuries, including hip fractures. Several studies have suggested that visual impairment contributes to falls, but studies have not used standardized definitions of visual impairment and have not examined injurious falls or fractures. We looked at the risk of hip fracture associated with visual impairment in those members of the Framingham Study Cohort who took part in the Framingham Eye Study in 1973-75. Of 2,633 subjects followed for 10 years after the eye exam, 110 sustained hip fractures. The fracture rates in those with moderately impaired (20/30 to 20/80) vision (8.5%) and poor (20/100 or worse) vision (11.3%) were higher than in those with good (20/25 or better) vision (3.0%). After adjustment for age, sex, weight, alcohol consumption, and (in women) estrogen use, the relative risk of fracture in those with moderate impairment was 1.54 (95% CI = 0.95-2.49), while for those with poor vision, the relative risk was 2.17 (95% CI = 1.24-3.80). Of note, those with moderately impaired vision in one eye and good vision in the other had a higher risk of fracture (relative risk = 1.94) than those with a similar degree of binocular impairment (relative risk = 1.11). Poor vision in one or both eyes was linked to an elevated fracture risk. This suggests that good stereoscopic vision may be necessary to prevent falls. The risk of fracture with poor and moderately impaired vision combined was increased in women (relative risk = 1.96, 95% CI = 1.23-3.11) but not in men (relative risk = 0.79, 95% CI = 0.23-2.72).(ABSTRACT TRUNCATED AT 250 WORDS)