Nandini Deshpande

Activity Restriction Induced by Fear of Falling and Objective and Subjective Measures of Physical Function : A Prospective Cohort Study

OBJECTIVES: To examine whether activity restriction specifically induced by fear of falling (FF) contributes to greater risk of disability and decline in physical function.

Psychological, physical, and sensory correlates of fear of falling and consequent activity restriction in the elderly: the InCHIANTI study.

Deshpande N, Metter EJ, Bandinelli S, Lauretani F, Windham BG, Ferrucci L: Psychological, physical, and sensory correlates of fear of falling and consequent activity restriction in the elderly: the InCHIANTI study. Am J Phys Med Rehabil 2008;87:354–362. Objective:To identify psychological, physical, and sensory function parameters that are specifically associated with fear of falling (FF) and fear-induced activity restriction in a population-based sample of older adults. Design:FF, fear-induced activity restriction, cognition, depression, personal mastery, chair-stand performance, standing balance, lower-limb and grip strength, visual acuity and contrast sensitivity, and vibrotactile sensitivity were evaluated in the population-based, older cohort (n = 926, age ≥ 65) enrolled in the InCHIANTI study. Results:Nearly 50% participants reported FF. Of these, 65% reported some activity restriction. Personal mastery (P < 0.001) and chair-standing performance (P = 0.001) were independently associated with FF. In those who did not have depression, personal mastery, standing balance, lower-limb strength, and visual contrast sensitivity were associated with activity restriction (P < 0.001–0.011). In those who were depressed, total FF was the major factor strongly associated with activity restriction (P < 0.001), with marginal but significant associations for cognition (P = 0.027) and standing balance (P = 0.015). Conclusion:Psychological and physical factors are independently associated with FF. Presence of depression possibly modulates which factors, in addition to fear of falling, affect fear-induced activity restriction. A longitudinal study is warranted to substantiate causal relationships.

Visual–vestibular interaction during goal directed locomotion: effects of aging and blurring vision

Normal vision overrides perturbed vestibular information for the optimization of performance during goal directed locomotion, suggesting down-regulation of vestibular gain. However, it is not known if the responses to vestibular perturbation are accentuated when vision is impaired. Furthermore, both visual and vestibular systems deteriorate with age. It is not clear, however, how age-related decline in these sensory systems influences visual–vestibular interaction. Therefore, the dual purpose of the present study was to investigate the effects of aging and blurring vision, that simulated the consequences of cataracts, on visual–vestibular interaction. Young and healthy elderly walked to a target located straight ahead with either normal or blurring vision. On randomly selected trials vestibular system perturbation was achieved by applying transmastoidal galvanic vestibular stimulation (GVS). Two different galvanic stimulation intensities were used to provide insight into scaling effect of vestibular perturbation on locomotor performance and how age and vision influences this scaling effect. Maximum path deviation, frontal trunk tilt and postural coordination in the mediolateral direction were evaluated. The magnitude of the path deviation and the trunk tilt response were scaled to the magnitude of the vestibular perturbation in older adults independent of the visual condition. Older participants demonstrated increased coupling of the head and trunk segments irrespective of visual and vestibular perturbations. The results suggest that when visual information was available, the vestibular input reweighting was less effective in older individuals, as shown by the scaled responses to the GVS intensities and the inability to converge efficiently towards the target.

Physiological correlates of age-related decline in vibrotactile sensitivity

The purpose of this study was to describe age-related changes in vibrotactile sensitivity in participants of the Baltimore Longitudinal Study of Aging and to identify factors that are associated with impairment in vibrotactile sensitivity independent of age. Participants (n=523, age: 26-95 years) underwent measurements of vibration perception threshold (VPT, 100Hz) under the 2nd metatarsal head, glucose tolerance, serum inflammatory markers, nerve conduction parameters, movement time and cognition. Univariate and multivariate regression analyses were performed to identify factors that predicted VPT independent of age. Structural equation modeling was used to describe relationships between these variables. VPT was progressively higher with older age. Adjusting for age and height, VPT was similar in men and women and the slope of age-related decline was similar in the two genders. Age, height, peroneal nerve conduction velocity and peroneal nerve amplitude were independent predictors of VPT. Structural equation model demonstrated a direct relationship between peripheral nerve function and VPT. Height and circulating inflammatory markers may influence age-related decline in vibrotactile sensitivity through their negative impacts on peripheral nerve function.

Performance on Five Times Sit-to-Stand Task as a Predictor of Subsequent Falls and Disability in Older Persons

Objectives: To investigate whether the performance on 5 times sit-to-stand test (5tSTS) can predict subsequent falls, fall-related fracture, and activities of daily living (ADL) and instrumental activities of daily living (IADL) disability in older persons. Methods: A total of 948 older adults (age ≥ 60) participated in this study. Ability and the time to finish 5tSTS were recorded at baseline. Number of falls, fall-related fractures, and the ability to complete ADL and IADL without assistance were recorded retrospectively at baseline and at the 3-year follow-up. Results: Inability to complete 5tSTS was a marginal predictor of falls (OR = 4.22) and a significant predictor of ADL- (OR = 24.70) and IADL-related disability (OR = 17.10) at 3-year follow-up. The need of longer time to complete 5tSTS was predictive of developing IADL-related disability at 3-year follow-up (OR = 4.22 [> 16.6 s]; OR = 2.49 [13.7 – 16.6 s]). Discussion: 5tSTS is an easily administered tool which can be used to predict subsequent ADL- and IADL-related disability.

Interpreting Fear of Falling in the Elderly: What Do We Need to Consider?

ABSTRACT Purpose: Fear of falling (FF) is a serious problem in elderly. Available scales quantify FF by generating an aggregate total FF score disregarding the environment in which fear is expressed. This study examined the differences in psychosocial and physical characteristics and global functional capabilities between the elderly who experienced FF exclusively for activities usually performed in community environments and those who reported FF only for home‐based activities. Methods: Older participants (age ≥ 65, n=1155) enrolled in the InCHIANTI study completed the evaluation of FF, personal mastery, depression, cognition, social support, lower limb strength, grip strength, balance, timed repeated sit‐to‐stand performance, visual acuity, and contrast sensitivity. Functional capacity measures included walking speed, ADL and IADL disability, self‐reported difficulty climbing steps without support and difficulty walking at least 400m. Only those who reported FF exclusively for activities usually performed in the community environment (n=232) or in home environment (n=110) were included in the analysis. Results: Multivariate analysis of variance revealed that those who reported FF exclusively for home‐based activities were significantly worse in psychosocial and physical characteristics measured (F(1,339)= 4.27; p < 0.01) and were also less able in all global functional capacity measures (p= 0.04 to < 0.01). Conclusions: There are significant characteristic and functional differences between the older persons who have FF performing community environment activities and those who express FF in home environment activities. The results strongly indicate the need to classify FF according to the environment or alternatively, to derive an aggregate score by appropriately weighting according to the environment, for valid interpretation of FF.

Association of Lower Limb Cutaneous Sensitivity with Gait Speed in the Elderly : The Health ABC Study

Deshpande N, Ferrucci L, Metter J, Faulkner KA, Strotmeyer E, Satterfield S, Schwartz A, Simonsick E: Association of lower limb cutaneous sensitivity with gait speed in the elderly. Am J Phys Med Rehabil 2008;87:921–928. Objective:To examine the association of fast-adapting receptor-mediated vibrotactile sensitivity and slow-adapting receptor-mediated pressure sensitivity with self-selected usual gait speed and gait speed over a challenging narrow (20 cm wide) course. Design:Participants from the population-based older cohort of the Health ABC study were included (n = 1721; age: 76.4 ± 2.8 yrs). Usual gait speed over 6 m and gait speed over a 6-m narrow course were measured. Vibration perception threshold (100 Hz) was measured on the plantar surface, and monofilament testing (1.4 and 10 g) was performed on the dorsum of the great toe. Covariates including knee extensor torque, standing balance, visual acuity and contrast sensitivity, knee pain, depressive symptoms, high fasting glucose levels, and peripheral arterial disease were evaluated. Results:Vibrotactile and monofilament sensitivity were significantly worse in slower gait speed groups in both walking conditions (P < 0.001 to P = 0.015). Adjusting for covariates, vibrotactile (P < 0.001) but not monofilament sensitivity (P = 0.655) was independently associated with self-selected normal gait speed. Neither sensory function was associated with narrow-base gait speed. Conclusions:In the elderly, poor lower limb vibrotactile sensitivity measured on the plantar surface of the great toe, but not the pressure sensitivity as measured by monofilament testing on the dorsum of the great toe, is independently associated with slower self-selected normal gait speed. Narrow-based walking seems to depend on other neuromuscular mechanisms.

Falls and Balance Impairments in Older Adults with Type 2 Diabetes: Thinking Beyond Diabetic Peripheral Neuropathy

Older adults with type 2 diabetes have significantly higher incidence of falls than those without type 2 diabetes. The devastating consequences of falls include declines in mobility, activity avoidance, institutionalization and mortality. One of the most commonly identified risk factors associated with falls is impaired balance. Balance impairments and subsequent increased fall risk in older adults with type 2 diabetes are most commonly associated with diabetic peripheral neuropathy (DPN). Consequently, DPN has been the central focus of falls prevention research and interventions for older adults with type 2 diabetes. However, isolated studies have identified adults with type 2 diabetes without overt complications of DPN to also be at increased fall risk. It is known that the ability to maintain balance is a complex skill that requires the integration of multiple sensorimotor and cognitive processes. Emerging evidence suggests that diabetes-related subtle declines in sensory functions (somatosensory, visual and vestibular), metabolic muscle function and executive functions may also contribute to increased fall risk in older adults with type 2 diabetes. Knowledge of these type 2 diabetes-related sensorimotor and cognitive deficits may help to broaden approaches to falls prevention in older adults with type 2 diabetes. Therefore, the purpose of this mini review is to describe the impact of type 2 diabetes on sensorimotor and cognitive systems that may contribute to increased fall risk in older adults with type 2 diabetes.

Effects of aging on whole body and segmental control while obstacle crossing under impaired sensory conditions.

The ability to safely negotiate obstacles is an important component of independent mobility, requiring adaptive locomotor responses to maintain dynamic balance. This study examined the effects of aging and visual-vestibular interactions on whole-body and segmental control during obstacle crossing. Twelve young and 15 older adults walked along a straight pathway and stepped over one obstacle placed in their path. The task was completed under 4 conditions which included intact or blurred vision, and intact or perturbed vestibular information using galvanic vestibular stimulation (GVS). Global task performance significantly increased under suboptimal vision conditions. Vision also significantly influenced medial-lateral center of mass displacement, irrespective of age and GVS. Older adults demonstrated significantly greater trunk pitch and head roll angles under suboptimal vision conditions. Similar to whole-body control, no GVS effect was found for any measures of segmental control. The results indicate a significant reliance on visual but not vestibular information for locomotor control during obstacle crossing. The lack of differences in GVS effects suggests that vestibular information is not up-regulated for obstacle avoidance. This is not differentially affected by aging. In older adults, insufficient visual input appears to affect ability to minimize anterior-posterior trunk movement despite a slower obstacle crossing time and walking speed. Combined with larger medial-lateral deviation of the body COM with insufficient visual information, the older adults may be at a greater risk for imbalance or inability to recover from a possible trip when stepping over an obstacle.

Sex-specific age associations of ankle proprioception test performance in older adults: results from the Baltimore Longitudinal Study of Aging

OBJECTIVES this study was aimed to test the hypothesis that ankle proprioception assessed by custom-designed proprioception testing equipment changes with ageing in men and women. METHODS ankle proprioception was assessed in 289 participants (131 women) of the Baltimore Longitudinal Study of Aging (BLSA); the participants aged 51-95 years and were blinded during testing. RESULTS the average minimum perceived ankle rotation was 1.11° (SE = 0.07) in women and 1.00° (SE = 0.06) in men, and it increased with ageing in both sexes (P < 0.001, for both). Ankle tracking performance, which is the ability to closely follow with the left ankle, a rotational movement induced on the right ankle by a torque motor, declines with ageing in both men and women (P = 0.018 and P = 0.011, respectively). CONCLUSIONS a simple, standardised method for assessing ankle proprioception was introduced in this study using a customized test instrument, software and test protocol. Age-associated reduction in ankle proprioception was confirmed from two subtests of threshold and tracking separately for women and men. Findings in this study prompt future studies to determine whether these age-associated differences in the threshold for passive motion detection and movement tracking are evident in longitudinal study and how these specific deficits in ankle proprioception are related to age-associated chronic conditions such as knee or hip osteoarthritis and type II diabetes and affect daily activities such as gait.