Age-related changes in upper extremity performance of elderly people: a longitudinal study

Synthesize Personalized Training for Robot-Assisted Upper Limb Rehabilitation With Diversity Enhancement

For upper limb rehabilitation, the robot-assisted technique in combination with serious games requires well-specified training plans. For the best quality of the rehabilitation process, customized game levels for each user are desired, while it is labor-intensive to design and adjust game levels for different individuals. We work on generating training content for a desktop end-effector rehabilitation robot and propose a method to automatically generate individualized training plans. By modeling the search of the training motions as finding optimal hand paths and trajectories, we introduce solving the design problem with a multi-objective optimization (MO) solver. We further improve the MO solver to enhance the diversity of the solutions. With the proposed approach, our system is capable of automatically generating various training plans considering the training intensity and dexterity of each joint in the upper limb. In addition, the enhanced diversity avoids repeated training plans, which helps motivate the user in the rehabilitation. We test our method with different requirements on the training plans and validate the solutions.

Therapy effect on hand function after home use of a wearable assistive soft-robotic glove supporting grip strength

BACKGROUND

Soft-robotic gloves with an assist-as-needed control have the ability to assist daily activities where needed, while stimulating active and highly functional movements within the user's possibilities. Employment of hand activities with glove support might act as training for unsupported hand function.

OBJECTIVE

To evaluate the therapeutic effect of a grip-supporting soft-robotic glove as an assistive device at home during daily activities.

METHODS

This multicentre intervention trial consisted of 3 pre-assessments (averaged if steady state = PRE), one post-assessment (POST), and one follow-up assessment (FU). Participants with chronic hand function limitations were included. Participants used the Carbonhand glove during six weeks in their home environment on their most affected hand. They were free to choose which activities to use the glove with and for how long. The primary outcome measure was grip strength, secondary outcome measures were pinch strength, hand function and glove use time.

RESULTS

63 patients with limitations in hand function resulting from various disorders were included. Significant improvements (difference PRE-POST) were found for grip strength (+1.9 kg, CI 0.8 to 3.1; p = 0.002) and hand function, as measured by Jebson-Taylor Hand Function Test (-7.7 s, CI -13.4 to -1.9; p = 0.002) and Action Research Arm Test (+1.0 point, IQR 2.0; p≤0.001). Improvements persisted at FU. Pinch strength improved slightly in all fingers over six-week glove use, however these differences didn't achieve significance. Participants used the soft-robotic glove for a total average of 33.0 hours (SD 35.3), equivalent to 330 min/week (SD 354) or 47 min/day (SD 51). No serious adverse events occurred.

CONCLUSION

The present findings showed that six weeks use of a grip-supporting soft-robotic glove as an assistive device at home resulted in a therapeutic effect on unsupported grip strength and hand function. The glove use time also showed that this wearable, lightweight glove was able to assist participants with the performance of daily tasks for prolonged periods.

A tensor decomposition reveals ageing-induced differences in muscle and grip-load force couplings during object lifting

Do motor patterns of object lifting movements change as a result of ageing? Here we propose a methodology for the characterization of these motor patterns across individuals of different age groups. Specifically, we employ a bimanual grasp-lift-replace protocol with younger and older adults and combine measurements of muscle activity with grip and load forces to provide a window into the motor strategies supporting effective object lifts. We introduce a tensor decomposition to identify patterns of muscle activity and grip-load force ratios while also characterizing their temporal profiles and relative activation across object weights and participants of different age groups. We then probe age-induced changes in these components. A classification analysis reveals three motor components that are differentially recruited between the two age groups. Linear regression analyses further show that advanced age and poorer manual dexterity can be predicted by the coupled activation of forearm and hand muscles which is associated with high levels of grip force. Our findings suggest that ageing may induce stronger muscle couplings in distal aspects of the upper limbs, and a less economic grasping strategy to overcome age-related decline in manual dexterity.

The impact of age-related increase in passive muscle stiffness on simulated upper limb reaching

Ageing changes the musculoskeletal and neural systems, potentially affecting a person's ability to perform daily living activities. One of these changes is increased passive stiffness of muscles, but its contribution to performance is difficult to separate experimentally from other ageing effects such as loss of muscle strength or cognitive function. A computational upper limb model was used to study the effects of increasing passive muscle stiffness on reaching performance across the model's workspace (all points reachable with a given model geometry). The simulations indicated that increased muscle stiffness alone caused deterioration of reaching accuracy, starting from the edges of the workspace. Re-tuning the model's control parameters to match the ageing muscle properties does not fully reverse ageing effects but can improve accuracy in selected regions of the workspace. The results suggest that age-related muscle stiffening, isolated from other ageing effects, impairs reaching performance. The model also exhibited oscillatory instability in a few simulations when the controller was tuned to the presence of passive muscle stiffness. This instability is not observed in humans, implying the presence of natural stabilizing strategies, thus pointing to the adaptive capacity of neural control systems as a potential area of future investigation in age-related muscle stiffening.

Analysis of Vibration Frequency and Direction for Facilitating Upper-Limb Muscle Activity

We aimed to determine the effect of vibration frequency and direction on upper-limb muscle activation using a handheld vibrator. We recruited 19 healthy participants who were instructed to hold a handheld vibrator in their dominant hand and maintain the elbow at 90° flexion, while vertical and horizontal vibrations were applied with frequencies of 15, 30, 45, and 60 Hz for 60 s each. Surface electromyography (EMG) measured the activities of the flexor digitorum superficialis (FDS), flexor carpi radialis (FCR), extensor carpi ulnaris (ECU), extensor carpi radialis (ECR), biceps, triceps, and deltoid anterior muscles. EMG changes were evaluated as the difference in muscle activity between vibration and no-vibration (0 Hz) conditions. Muscle activity was induced under vibration conditions in both vertical and horizontal (p < 0.05) directions. At 45 Hz, FDS and FCR activities increased during horizontal vibrations, compared with those during vertical vibrations. ECU activity significantly increased under 15-Hz vertical vibrations compared with that during horizontal vibrations. Vibrations from the handheld vibrator significantly induced upper-limb muscle activity. The maximum muscle activations for FDS, ECR, ECU, biceps, and triceps were induced by 45-Hz horizontal vibration. The 60-Hz vertical and 30-Hz horizontal vibrations facilitated maximum muscle activations for the FCR and deltoid anterior, respectively.

Validation of Vibration Exercises on Enhancing Muscle Strength and Upper Limb Functionality among Pre-Frail Community-Dwelling Older Adults

Pre-frail older adults require appropriate exercise to enhance muscle strength as well as upper limb functionality. We developed a handheld vibrator and evaluated its effectiveness in enhancing muscle strength compared to conventional exercises among pre-frail community-dwelling older adults. Thirty-one pre-frail older adults (aged 75.5 ± 5.1 years) were recruited and randomly allocated to a vibration group (VG) and control group (CG). The VG underwent 20 minutes of vibration (frequency: 30 Hz, amplitude: 5 mm, horizontal vibration) using a handheld vibrator as well as 40 minutes of conventional exercise. The CG received 60 minutes of conventional exercise only. The primary outcome was muscle strength assessment (kg), and the secondary outcome included activities of daily living and instrumental activities of daily living scores. The comparisons between the outcome measures revealed no significant differences at the baseline level. Muscle strength of the dominant (ß = 2.49, p = 0.002) and non-dominant (ß = 1.89, p = 0.02) wrist flexion, brachioradialis (ß = 3.8, p = 0.01), and biceps brachii (ß = 3.02, p = 0.02) in the dominant upper limbs was significantly increased among the VG. The vibration intervention can enhance muscle strength in the upper limbs among pre-frail older adults.

Use of the Kinect sensor measured three-dimensional reachable workspace to assess the upper extremity function in older adults

BACKGROUND

We explored the utility of Kinect sensor-based upper extremity reachable workspace measure in healthy adults aged over 65 years.

METHODS

Forty-three healthy older subjects (19 men and 24 women) aged over 65 years and 22 healthy young subjects (11 men and 11 women) were included. All participants were ambulatory and perform the activities of daily living independently. Three-dimensional reachable workspace data were acquired for both arms using the Kinect sensor. We evaluated hand grip strength, manual muscle shoulder strength, and the active shoulder ranges of motion of the dominant and non-dominant sides. We assessed upper limb function using the Disabilities of Arm, Shoulder, and Hand (DASH) instrument and the health-related quality of life employing the descriptive EQ-5D-5L system.

FINDINGS

The quadrant 3 relative surface area in older adults was significantly smaller than that of young adults (both dominant and non-dominant sides), while the total and quadrants 1, 2, and 4 relative surface areas did not differ between older and young adults. However, the quadrant 3 relative surface area did not correlate with the DASH or EQ5D scores. The total and quadrant 1, 2, and 4 relative surface areas of the dominant side significantly correlated with the DASH score. The quadrant 4 relative surface area of the dominant side significantly correlated with the EQ5D score.

INTERPRETATION

Kinect sensor-based, three-dimensional, reachable workspace analysis may be useful to evaluate upper limb function in older adults.

Validation of a graphic test to quantitatively assess the dominant hand dexterity

Dexterity dysfunction is a key feature of disability in many neurological and non-neurological diseases. The Nine-Hole Peg Test (NHPT) is the most used test to assess hand dexterity in clinical practice but presents limitations. A new graphic test to enhance objective evaluation of the of the dominant hand dexterity is proposed. The task consists in drawing a continuous line in paths composed by a part with multiple orthogonal changes of direction ('meander'), and a second part derived from the Archimedean spiral ('spiral'). The test was validated in 200 healthy controls and 93 neurological patients. 48 patients performed also the NHPT. Several parameters were analyzed, among which total time, total length, number of touches and number of crossings. Healthy subjects display statistically significant differences with respect to pathological subjects in the case of total time, number of touches, and number of crossings (p<0.001), but not in the case of total length (p = 0.27) needed to complete the second sheet. Moreover, healthy controls display a learning effect, the time needed to complete the second sheet was significantly lower than for the first sheet (p<0.001), and an inverse correlation with age was observed (r = 0.56, p<0.001). The comparison between the NHPT and the new test showed a strong positive correlation (r = 0.71, p<0.001) whereas touches and crossing a weak positive one (r = 0.35, p = 0.01). The new test distinguishes between a slow but precise performance and a fast but imprecise performance, thus providing additional information with respect to NHPT.

Effect on Hand Function After Six-week Use of a Wearable Soft-Robotic Glove Assisting ADL: Interim Results of an Ongoing Clinical Study

In an ongoing study, an assistive wearable soft-robotic glove is tested at home for 6 weeks by subjects with decreased handgrip strength, due to different hand injuries or diseases, to assess whether use of this assistive grip-supporting glove will result in improved hand strength/ function. An interim analysis of the available dataset of 46 participants showed that (unsupported) grip strength and hand function improved after using the soft-robotic glove as assistive aid during activities of daily living (ADLs) during 6 weeks at home. After glove use is ended, this is maintained for at least 4 weeks. Considering that in the current situation the analysis is underpowered, these interim results are promising for finding a clinical (therapeutic) effect of using a soft-robotic glove as assistance during ADLs. If this is the case, this might open up entirely new opportunities for extending rehabilitation into people's homes, while also providing them with assistance to directly support performance of daily activities. Such a combination is becoming available with the development of mature and user-friendly wearable soft-robotic devices. This would enable very high doses of training throughout the day, in the most functional, task-specific way possible, and possibly prevention of learned non-use.

Aging and Bimanual Effects on Finger Center of Pressure during Precision Grip: Different Strategies for Spatial Stability

The purpose of this study was to examine aging and bimanual effects on finger spatial stability during precision grip. Twenty-one older and 21 younger adults performed precision grip tasks consisting of a single task (grip and lift an object with the thumb and index finger) and a dual task (the grip-lifting task with one hand and a peg board task with the other hand). The center of pressure (COP) trajectory and the grip force were evaluated using a pressure sensor with a high spatial resolution. In the COP trajectory, the main effects of age for the thumb (F_1,140 = 46.17, p < 0.01) and index finger (F_1,140 = 22.14, p < 0.01) and task difficulty for the thumb (F_1,140 = 6.47, p = 0.01) were significant based on ANCOVA. The COP trajectory was statistically decreased in the older adults. The COP trajectory was also decreased in the dual task, regardless of age. The results suggest the existence of a safety strategy to prioritize the spatial stability in the elderly group and in the dual task. This study provides new insights into the interpretation of the COP trajectory.

The role of eye movements, attention, and hand movements on age-related differences in pegboard tests

Well-documented manual dexterity impairments in older adults may critically depend on the processing of visual information. The purpose of this study was to determine age-related changes in eye and hand movements during commonly used pegboard tests and the association with manual dexterity impairments in older adults. The relationship between attentional deficits and manual dexterity was also assessed. Eye movements and hand kinematics of 20 young (20-38 yr) and 20 older (65-85 yr) adults were recorded during 9-Hole Pegboard, Grooved Pegboard, and a visuospatial dual test. Results were compared with standardized tests of attention (The Test of Everyday Attention and Trail Making Test) that assess visual selective attention, sustained attention, attentional switching, and divided attention. Hand movement variability was 34% greater in older versus young adults when placing the pegs into the pegboard and this was associated with decreased pegboard performance, providing further evidence that increased movement variability plays a role in dexterity impairments in older adults. Older adults made more corrective saccades and spent less time gazing at the pegboard than young adults, suggesting altered visual strategies in older compared with young adults. The relationship between pegboard completion time and Trail Making Test B demonstrates an association between attentional deficits and age-related pegboard impairments. Results contribute novel findings of age-associated changes in eye movements during a commonly used manual dexterity task and offer insight into potential mechanisms underlying hand motor impairments in older adults.NEW & NOTEWORTHY This eye tracking study contributes novel findings of age-associated changes in eye movements during the commonly used pegboard tests of manual dexterity, including a greater number of corrective saccades and lesser time gazing at the pegboard holes in older compared with young adults. An association between attentional deficits and dexterity impairments in older adults is also highlighted. Results shed light on potential mechanisms underlying well-documented motor deficits in older adults.

Fear of Falling: Significant Barrier in Fall Prevention Approaches

Fear of falling is a critical component in fall prevention approaches; however, it is often overlooked in the majority of fall prevention exercises. Alternative fall prevention approaches that take fear of falling into account are necessary. This article discusses fall prevention activities that are feasible for individuals with limited mobility who have an increased fear of falling. Health care providers should consider the degree to which a patient has a fear of falling and recommend activities that fit most to their patient's comfort level.

The iHand clinical trial protocol: multi-center uncontrolled intervention study to examine the therapeutic effect of a soft-robotic glove as assistive device to support people with impaired hand strength during activities of daily living (Preprint)

Background

Decline of hand function, especially reduced hand strength, is a common problem that can be caused by many disorders and results in difficulties performing activities of daily living. A wearable soft robotic glove may be a solution, enabling use of the affected arm and hand repeatedly during functional daily activities and providing intensive and task-specific training simultaneously with assistance of hand function.

Objective

We aim to investigate the therapeutic effect of an assistive soft robotic glove (Carbonhand).

Methods

This multicenter uncontrolled intervention study consists of 3 preassessments (T0, T1, and T2), a postassessment (T3), and a follow-up assessment (T4). Participants are patients who experience hand function limitations. For the intervention, participants will use the glove during activities of daily living at home for 6 weeks, with a recommended use of at least 180 minutes per week. The primary outcome measure is handgrip strength, and secondary outcome measures are related to functional arm and hand abilities, amount of glove use, and quality of life.

Results

The first participant was included on June 25, 2019. Currently, the study has been extended due to the COVID-19 pandemic; data collection and analysis are expected to be completed in 2022.

Conclusions

The Carbonhand system is a wearable assistive device, allowing performance of functional activities to be enhanced directly during functional daily activities. At the same time, active movement of the user is encouraged as much as possible, which has potential to provide highly intensive and task-specific training. As such, it is one of the first assistive devices to incorporate assist-as-needed principles. This is the first powered clinical trial that investigates the unique application of an assistive grip-supporting soft robotic glove outside of clinical settings with the aim to have a therapeutic effect.

Trial Registration

Netherlands Trial Register NTR NL7561; https://www.trialregister.nl/trial/7561

International Registered Report Identifier (IRRID)

DERR1-10.2196/34200

The organizational principles of de-differentiated topographic maps in somatosensory cortex

Topographic maps are a fundamental feature of cortex architecture in the mammalian brain. One common theory is that the de-differentiation of topographic maps links to impairments in everyday behavior due to less precise functional map readouts. Here, we tested this theory by characterizing de-differentiated topographic maps in primary somatosensory cortex (SI) of younger and older adults by means of ultra-high resolution functional magnetic resonance imaging together with perceptual finger individuation and hand motor performance. Older adults' SI maps showed similar amplitude and size to younger adults' maps, but presented with less representational similarity between distant fingers. Larger population receptive field sizes in older adults' maps did not correlate with behavior, whereas reduced cortical distances between D2 and D3 related to worse finger individuation but better motor performance. Our data uncover the drawbacks of a simple de-differentiation model of topographic map function, and motivate the introduction of feature-based models of cortical reorganization.

The impact of movement sonification on haptic perception changes with aging

Combining multisensory sources is crucial to interact with our environment, especially for older people who are facing sensory declines. Here, we examined the influence of textured sounds on haptic exploration of artificial textures in healthy younger and older adults by combining a tactile device (ultrasonic display) with synthetized textured sounds. Participants had to discriminate simulated textures with their right index while they were distracted by three disturbing, more or less textured sounds. These sounds were presented as a real-time auditory feedback based on finger movement sonification and thus gave the sensation that the sounds were produced by the haptic exploration. Finger movement velocity increased across both groups in presence of textured sounds (Rubbing or Squeaking) compared to a non-textured (Neutral) sound. While young adults had the same discrimination threshold, regardless of the sound added, the older adults were more disturbed by the presence of the textured sounds with respect to the Neutral sound. Overall, these findings suggest that irrelevant auditory information was taken into account by all participants, but was appropriately segregated from tactile information by young adults. Older adults failed to segregate auditory information, supporting the hypothesis of general facilitation of multisensory integration with aging.

The Effects of Ageing on Tactile Function in Humans

Ageing is accompanied by a steady decline in touch sensitivity and acuity. Conversely, pleasant touch, such as experienced during a caress, is even more pleasant in old age. There are many physiological changes that might explain these perceptual changes, but researchers have not yet identified any specific mechanisms. Here, we review both the perceptual and structural changes to the touch system that are associated with ageing. The structural changes include reduced elasticity of the skin in older people, as well as reduced numbers and altered morphology of skin tactile receptors. Effects of ageing on the peripheral and central nervous systems include demyelination, which affects the timing of neural signals, as well as reduced numbers of peripheral nerve fibres. The ageing brain also undergoes complex changes in blood flow, metabolism, plasticity, neurotransmitter function, and, for touch, the body map in primary somatosensory cortex. Although several studies have attempted to find a direct link between perceptual and structural changes, this has proved surprisingly elusive. We also highlight the need for more evidence regarding age-related changes in peripheral nerve function in the hairy skin, as well as the social and emotional aspects of touch.

Premature oral pre-shaping for feeding in elderly population with risk of aspiration pneumonia

The aim of this study was to determine the abnormal hand and mouth behavior before actual swallowing for eating in elderly people with high risk of aspiration pneumonia. Ten elderly people with a diagnosis of aspiration pneumonia (EAP), 15 healthy elderly (HE) people, and 21 young adults (YA) were enrolled. The feeding time and the timing of the maximum distance between the upper and lower lips were extracted using a motion analyzer during self-feeding and assisted-feeding. The results showed that feeding time in EAP was significantly longer than that for the other groups in self- and assisted-feeding. In self-feeding, the timing of mouth-preparation in the EAP group was significantly earlier than that in the other groups; conversely, in assisted-feeding, the timing in EAP was significantly delayed. Our results indicate that abnormal preparation of mouth-shape and movement time of hand before actual swallowing in both self- and assisted-feeding may exist in elderly people with previous experience of aspiration pneumonia.

The effects of age on response time, accuracy, and shoulder/arm kinematics during hammering

The aim of this study was to investigate the effects of age on response time and accuracy during a hammering task. Older male workers aged 51-69 years (older group: OG, n = 23) and younger male reference individuals aged 25-36 years (younger group: YG, n = 16) performed the experiment. Response time, accuracy, and 3D shoulder/arm kinematics were acquired using motion capture. The effects of age were investigated using linear mixed model analysis. Response times were significantly longer for OG compared with YG (P < 0.001) while no marked differences in the accuracy was observed (P = 0.729). OG showed less hammer displacement and smaller range of motion in the shoulder. Although older workers seemed to use a less biomechanical demanding motor strategy, their response times during hammering were about twice that of younger individuals.

Feasibility of a Home-Based Tablet App for Dexterity Training in Multiple Sclerosis: Usability Study

BACKGROUND

Persons with multiple sclerosis (MS) often experience dexterous difficulties during the performance of activities of daily living, such as fastening buttons, handling coins, or writing, therefore impacting their health-related quality of life. Mobile health (mHealth) solutions, such as tablet apps, may be used to train impaired dexterous skills. The feasibility of a tablet app-based dexterity home-based intervention in MS (TAD-MS) has not been explored yet in persons with MS.

OBJECTIVE

The aim of this pilot study was to evaluate the feasibility and usability of home-based dexterity training with a tablet app in both persons with MS and healthy subjects.

METHODS

A total of 9 persons with MS, aged 35-71 years, with an Expanded Disability Status Scale score between 2 and 7.5, performed the TAD-MS for 4 weeks, five times a week, with each training session lasting approximately 30 minutes. Participants' impaired dexterity was measured by the Nine-Hole Peg Test. A total of 10 age-matched healthy subjects also tested and rated the usability of the app. Outcome measures were the adherence rate as well as usability measured by the System Usability Scale and a Custom User Engagement Questionnaire (CUEQ).

RESULTS

High feasibility of the tablet app-based dexterity training program was shown by a 97% adherence rate to the training protocol (ie, mean 19.4/20 sessions completed, SD 0.8). High system usability scores (ie, mean 85.39%, SD 11.67) and overall high scores given in the CUEQ (ie, mean 8.2/10, SD 1.4) further point to high usability of the app. Neither demographic variables nor dexterity levels affected the use of the app.

CONCLUSIONS

This pilot study is the first to demonstrate high feasibility and usability of a new tablet app-based dexterity home-based training program among both persons with MS and healthy individuals. Whether this kind of training improves dexterity will need to be evaluated in a randomized controlled trial.

Home rehabilitation supported by a wearable soft-robotic device for improving hand function in older adults: A pilot randomized controlled trial

Background

New developments, based on the concept of wearable soft-robotic devices, make it possible to support impaired hand function during the performance of daily activities and intensive task-specific training. The wearable soft-robotic ironHand glove is such a system that supports grip strength during the performance of daily activities and hand training exercises at home.

Design

This pilot randomized controlled clinical study explored the effect of prolonged use of the assistive ironHand glove during daily activities at home, in comparison to its use as a trainings tool at home, on functional performance of the hand.

Methods

In total, 91 older adults with self-perceived decline of hand function participated in this study. They were randomly assigned to a 4-weeks intervention of either assistive or therapeutic ironHand use, or control group (received no additional exercise or treatment). All participants performed a maximal pinch grip test, Box and Blocks test (BBT), Jebsen-Taylor Hand Function Test (JTHFT) at baseline and after 4-weeks of intervention. Only participants of the assistive and therapeutic group completed the System Usability Scale (SUS) after the intervention period.

Results

Participants of the assistive and therapeutic group reported high scores on the SUS (mean = 73, SEM = 2). The therapeutic group showed improvements in unsupported handgrip strength (mean Δ = 3) and pinch strength (mean Δ = 0.5) after 4 weeks of ironHand use (p≤0.039). Scores on the BBT and JTHFT improved not only after 4 weeks of ironHand use (assistive and therapeutic), but also in the control group. Only handgrip strength improved more in the therapeutic group compared to the assistive and control group. No significant correlations were found between changes in performance and assistive or therapeutic ironHand use (p≥0.062).

Conclusion

This study showed that support of the wearable soft-robotic ironHand system either as assistive device or as training tool may be a promising way to counter functional hand function decline associated with ageing.

Age-related Declines in Sensorimotor Proficiency are Specific to the Tested Motor Skill Component

This study utilized a 3-degree of freedom robotic device (Wristbot) to examine wrist proprioception and eye-hand coordination in a cross-sectional sample of sixty-three young adults (19-29 years), 20 older young adults (30-49), and 17 older adults (50 years and older). Results indicated differences in the emergence of age-related declines in sensorimotor functioning depending on the tested motor skill component. While young adults exhibited smaller matching error and lower variability compared to older young adults and older adults on the proprioception task, we observed lower times-on-target and higher Linearity indices for participants older than 50 years of age compared to both young adults and older young adults. The present results provide necessary quantitative information on sensorimotor function in adulthood, and have implications for the early diagnosis and effective management of sensorimotor dysfunction in clinical settings using a commercially available robotic device.

Hand-Feel Touch Cues and Their Influences on Consumer Perception and Behavior with Respect to Food Products: A Review

There has been a great deal of research investigating intrinsic/extrinsic cues and their influences on consumer perception and purchasing decisions at points of sale, product usage, and consumption. Consumers create expectations toward a food product through sensory information extracted from its surface (intrinsic cues) or packaging (extrinsic cues) at retail stores. Packaging is one of the important extrinsic cues that can modulate consumer perception, liking, and decision making of a product. For example, handling a product packaging during consumption, even just touching the packaging while opening or holding it during consumption, may result in a consumer expectation of the package content. Although hand-feel touch cues are an integral part of the food consumption experience, as can be observed in such an instance, little has been known about their influences on consumer perception, acceptability, and purchase behavior of food products. This review therefore provided a better understanding about hand-feel touch cues and their influences in the context of food and beverage experience with a focus on (1) an overview of touch as a sensory modality, (2) factors influencing hand-feel perception, (3) influences of hand-feel touch cues on the perception of other sensory modalities, and (4) the effects of hand-feel touch cues on emotional responses and purchase behavior.

Establishing the Feasibility of a Tablet-Based Consent Process with Older Adults: A Mixed-Methods Study

Purpose of the Study

This mixed-methods study explored the feasibility and acceptability of using a tablet-based research consent process with adults aged ≥65 years.

Design and Methods

In the first phase, focus group participants reported on their perceptions of a tablet-based consent process. In the second phase, older adults were randomized to view either a tablet-based or paper-based consent for a mock clinical trial. Measurements included: time to complete, adverse/unexpected events, user-friendliness, immediate comprehension, and retention at a 1-week delay.

Results

Focus group participants (N = 15) expressed interest in the novel format, cautioning that peers would need comprehensive orientation to use the technology. In the randomized pilot (N = 20), retention was 100% and all participants completed the protocol without the occurrence of adverse/unexpected events. Although the participants took longer to complete the tablet-based consent than the paper-based version, user-friendliness, immediate comprehension, and retention of the tablet-based consent were similar to the paper-based consent.

Discussion and Implications

The findings suggest that a tablet-based consent process is feasible to implement with older adults and acceptable to this population, but we would underscore that efforts to optimize design of tablet-based consent forms for older adults are warranted.

Influence of aging and visual feedback on the stability of hand grip control in elderly adults

Aging causes a gradual decrease in maximal grip strength and leads many elderly people to have to rely on visual feedback to compensate for poorer muscle strength in performing daily activities and preventing accidents. Previous studies have investigated age and visual feedback-related changes in grip strength. However, little is known about methods of determining the quality and stability of hand grip strength control in the elderly, which is important for understanding their ability to generate grip force when handling objects with and without visual feedback in daily living. Therefore, the purpose of this study was to investigate the influence of aging and visual feedback on the stability of hand grip control in both hands in elderly adults. Forty-four healthy elderly persons (age 80.5 ± 4.53 years) and 36 young adults (age 32.69 ± 16.48 years) were recruited to execute grip force stability tasks using both hands at a 2 kg target force level. To perform the grip force stability task, the participants were asked to hold the dynamometer tightly in an attempt to achieve the target force level under visual and non-visual feedback conditions. Strength performances (grip force and coefficient of variation values) and stability of strength control (deviation error, variation error and force stability index values) for hand grip force stability tasks were calculated and analyzed. Compared with the visual feedback condition, the stability of grip force control in the hands of the young and elderly groups were significantly reduced in the non-visual feedback condition by 23.5%-57.1% (p < .05). The elderly group also showed significantly worse hand grip strength performances and stability of hand strength control than the young adult group (p < .05). Aging and non-visual feedback reduced the hand grip force output and stability of grip strength control of the hands. This may reveal the difficulty with manipulating hand-held objects in the absence of visual feedback while performing activities of daily living among the elderly.

Expectation of movement generates contrasting changes in multifinger synergies in young and older adults

Anticipatory synergy adjustment (ASA) is a feed-forward control mechanism that describes a continuous decrease in the stability of the current motor state beginning about 150 ms prior to a state transition. Recently, we described an associated phenomenon in which the system stability was reduced solely in response to a cue that generates an expectation of a state change, independent of whether the state change actually occurs. Both phenomena are of the same kind (stability reduction), but evoked by distinct antecedent conditions. Since, logically, cuing for movement must occur before the initiation of that movement, we named this new phenomenon 'Stage-1 ASA' and rechristened the well-established version 'Stage-2 ASA'. Here, we used a four-finger, isometric force production task to explore (1) the effect of healthy aging on Stage-1 ASA, and (2) if Stage-1 ASA resulted in a more rapid state change. Young and older adult participants produced 10% of their maximal force when they did not expect to produce any change in the force, and when they expected to change their force in an unknown direction and at an unknown time. In the latter condition, the 10% constant-force phase was followed by a choice reaction time task, in which the participants rapidly changed their force to follow a moving target presented on a computer monitor. Both young and older adults displayed equivalent amount of Stage-1 ASA. This was driven by a 42% reduction in finger-force variability in young adults. In contrast, it was driven by a 38% increase in finger-force variability in older adults. We speculate that the reduction in finger force variability assists the young adults in rapid state changes via two mechanisms: (1) the finger forces occupy a restricted set of states that are optimal for quick state transitions, and (2) lower variability during steady state translates into lower self-motion during state transition. Self-motion is the covariation between finger forces that fails to change the total force. The older adults are unable to adopt this strategy, and the increase in finger-force variability arises from (1) the adoption of an alternative strategy of destabilizing the attractor associated with the current state to facilitate state transitions and (2) the inability to coordinate multiple finger forces. Finally, older adults displayed longer reaction times than young adults, but a clear relation between Stage-1 ASA and consequent behavioral benefit in terms of reduced reaction time remained elusive.

Relationship between cognitive function and balance in a community-dwelling population in Japan

BACKGROUND

There has been no treatment found yet that cure dementia. Hence it is important to establish the evaluation index of cognitive decline before becoming dementia.

OBJECTIVE

The purpose of this study was to clarify the effective balance test indicating early cognitive decline by gender.

METHODS

A total of 218 volunteers (60 years of age and above) who participated in the Iwaki promotion health project in 2015 were recruited. We performed three balance tests: one leg standing test, functional reach test and static posturography, and we used mini-mental state examination (MMSE) to investigate cognitive function.

RESULTS

As a result of analysis of covariance, there was a statistically significant trend in only men that the more the MMSE score declined, the longer became the path length with both eyes opened and closed. In the result of multiple regression analysis, there was a significant negative association with MMSE score and path length with eyes opened or closed in men. There was no significant association with MMSE scores and balance tests in women.

CONCLUSION

The study suggests that static posturography might be a useful balance test to assess early cognitive decline in men.

Manual dexterity in young and healthy older adults. 1. Age- and gender-related differences in unimanual and bimanual performance

This study aimed to better characterize age-related differences in dexterity by using an integrative approach where movement times and kinematics were measured for both hands. Forty-five young (age 19-31) and 55 healthy older adults (age 60-88) were evaluated during unimanual and bimanual performance of the Purdue Pegboard Test. Gender effects were also assessed. From video-recorded data, movement times and kinematics were obtained for reaching, grasping, transport, and inserting. Results showed that older adults had longer movement times for grasping and inserting with the right hand, and across all movements with the left hand. Kinematic differences were found in path length, linear, and angular velocity. The patterns of slowing were similar in unimanual and bimanual tasks. Gender effects showed more slowing in older males than older females. Age differences in dexterity not only comprise slowing of movements but also kinematic alterations. The importance of gender in hand function was demonstrated.

The neurochemical basis of the contextual interference effect

Efficient practice organization maximizes learning outcome. Although randomization of practice as compared to blocked practice damages training performance, it boosts retention performance, an effect called contextual interference. Motor learning modulates the GABAergic (gamma-aminobutyric acid) system within the sensorimotor cortex (SM); however, it is unclear whether different practice regimes differentially modulate this system and whether this is impacted by aging. Young and older participants were trained on 3 variations of a visuomotor task over 3 days, following either blocked or random practice schedule and retested 6 days later. Using magnetic resonance spectroscopy, SM and occipital cortex GABA+ levels were measured before and after training during the first and last training days. We found that (1) behavioral data confirmed the contextual interference effects, (2) within-day occipital cortex GABA+ levels decreased in random and increased in blocked group. This effect was more pronounced in older adults; and (3) baseline SM GABA+ levels predicted initial performance. These findings indicate a differential modulation of GABA levels across practice groups that is amplified by aging.

Oral curcumin supplementation improves fine motor function in the middle-aged rhesus monkey

Aged individuals experience decreased fine motor function of the hand and digits, which could result, in part, from the chronic, systemic state of inflammation that occurs with aging. Recent research for treating age-related inflammation has focused on the effects of nutraceuticals that have anti-inflammatory properties. One particular dietary polyphenol, curcumin, the principal curcuminoid of the spice turmeric, has been shown to have significant anti-inflammatory effects and there is mounting evidence that curcumin may serve to reduce systemic inflammation. Therefore, it could be useful for alleviating age-related impairments in fine motor function. To test this hypothesis we assessed the efficacy of a dietary intervention with a commercially available optimized curcumin to ameliorate or delay the effects of aging on fine motor function of the hand of rhesus monkeys. We administered oral daily doses of curcumin or a control vehicle to 11 monkeys over a 14- to 18-month period in which they completed two rounds of fine motor function testing. The monkeys receiving curcumin were significantly faster at retrieving a food reward by round 2 of testing than monkeys receiving a control vehicle. Further, the monkeys receiving curcumin demonstrated a greater degree of improvement in performance on our fine motor task by round 2 of testing than monkeys receiving a control vehicle. These findings reveal that fine motor function of the hand and digits is improved in middle-aged monkeys receiving chronic daily administration of curcumin.

Factors affecting the results of the functional dexterity test

STUDY DESIGN

Cross-sectional study.

PURPOSE OF THE STUDY

The purpose of this study was to identify which demographic and anthropometric features affect performance (time) on the functional dexterity test (FDT).

METHODS

One hundred fifty-two healthy subjects between the ages of 20 and 80 years were included in this cross-sectional study. Demographic characteristics (age, gender, height, weight, and dominant hand) and anthropometric (the girths of the first 3 fingers) variables were recorded, and the FDT (net time and total score) was performed.

RESULTS

Hand dexterity (time) was slower in participants aged 60 years (35.7 ± 9.4 seconds) and older compared with those aged 40-59 (27.1 ± 7.2 seconds) years and 20-39 (23.9 ± 4.9 seconds) years (P < .001 for both) in dominant side.

DISCUSSION

There was no significant difference between males (29.1 ± 9 in dominant hands and 30.9 ± 9.5 in nondominant hands) and females (27.9 ± 8.4 in dominant hands and 30.8 ± 8.1 in nondominant hands) in all groups in terms of FDT net time. The factors associated with hand dexterity were age in dominant hands (R² = 0.321) and age and thickness of the second and third fingers in nondominant hands (R² = 0.282).

CONCLUSION

FDT scores increased with increasing age for both dominant and nondominant hands. Finger thickness, especially in nondominant hands, should be taken into account while evaluating FDT scores because of its negative effect on dexterity.

LEVEL OF EVIDENCE

Level 2.

Age-Related Decline in Anticipatory Motor Planning and Its Relation to Cognitive and Motor Skill Proficiency

Anticipatory motor planning abilities mature as children grow older, develop throughout childhood and are likely to be stable till the late sixties. In the seventh decade of life, motor planning performance dramatically declines, with anticipatory motor planning abilities falling to levels of those exhibited by children. At present, the processes enabling successful anticipatory motor planning in general, as do the cognitive processes mediating these age-related changes, remain elusive. Thus, the aim of the present study was (a) to identify cognitive and motor functions that are most affected by normal aging and (b) to elucidate key (cognitive and motor) factors that are critical for successful motor planning performance in young (n = 40, mean age = 23.1 ± 2.6 years) and older adults (n = 37, mean age = 73.5 ± 7.1 years). Results indicate that normal aging is associated with a marked decline in all aspects of cognitive and motor functioning tested. However, age-related declines were more apparent for fine motor dexterity, processing speed and cognitive flexibility. Furthermore, up to 64% of the variance in motor planning performance across age groups could be explained by the cognitive functions processing speed, response planning and cognitive flexibility. It can be postulated that anticipatory motor planning abilities are strongly influenced by cognitive control processes, which seem to be key mechanisms to compensate for age-related decline. These findings support the general therapeutic and preventive value of cognitive-motor training programs to reduce adverse effects associated with high age.

Systematic Review of the Clinical Application of Exposure Techniques to Community-Dwelling Older Adults with Anxiety

OBJECTIVES

Although exposure techniques are a first-line intervention for anxiety, clear evidence is lacking for their efficacy in treating the prevalent and debilitating condition of late life anxiety. This study sought to review the current literature on use of exposure with community-dwelling older patients.

METHODS

Searches of electronic databases were conducted to identify articles published through December 7, 2016. Inclusion criteria were: 1) sample age > 55, 2) therapy that included exposure, 3) anxiety as a target of the treatment. Exclusion criteria were: 1) not available in English, 2) no quantitative data, 3) inpatient setting. Methodological data and findings were extracted from the articles chosen for review.

RESULTS

The 54 eligible articles presented a total of 16 case studies, 9 uncontrolled trials, 24 controlled trials, and 6 secondary studies. A majority of the studies were conducted in the U.S.A with participants who received individual treatment. In vivo and imaginal exposure were the most frequently delivered techniques, and most treatments were multicomponent. Most studies found a reduction in anxiety symptoms.

CONCLUSIONS

Important research gaps need to be addressed.

CLINICAL IMPLICATIONS

The surveyed research provides a modest foundation of evidence for mental health practitioners who wish to incorporate exposure into treatment plans.

Tai Chi Can Improve Postural Stability as Measured by Resistance to Perturbation Related to Upper Limb Movement among Healthy Older Adults

Purpose. The aim of the study was to examine the effects of Tai Chi (TC) training on postural control when upright standing was perturbed by upper limb movement. Methods. Three groups, TC, Brisk walk (BW), and sedentary (SE), of thirty-six participants aged from 65 to 75 years were recruited from local community centers. Participants performed static balance task (quiet standing for 30 s with eyes open and closed) and fitting task (two different reaching distances X three different opening sizes to fit objects through). During tasks, the COP data was recorded while standing on the force plate. Criteria measures calculated from COP data were the maximum displacement in anterior-posterior (AP) and medial-lateral (ML) directions, the 95% confidence ellipse area (95% area), and the mean velocity. Results. No significant effect was observed in the static balance task. For fitting tasks, the group effect was observed in all directions on COP 95% area (p < 0.05) and the TC group showed reduced area. The tests of subject contrasts showed significant trends for reaching different distances and fitting different openings conditions in all directions, the 95% area, and the mean velocity (p < 0.05). Conclusion. Compared to the other two groups, long-term TC exercise helps in reducing the effects of upper body perturbation as measured by posture sway.

A wearable soft-robotic glove enables hand support in ADL and rehabilitation: A feasibility study on the assistive functionality

Background

Elderly people frequently experience a decline in hand function, due to ageing or diseases. This leads to decreased independence in activities of daily living (ADL). Assistive technology may enhance independence.

Objectives

The objective of this paper was to explore user acceptance of an affordable wearable soft-robotic glove (ironHand (iH) system), that supports grip and hand opening in ADL. In addition, functional performance with the iH system was explored.

Methods

For this study 28 elderly people used the iH system across two sessions. During these sessions, participants performed six functional tasks with and without the iH system. Outcome measures were System Usability Scale (SUS), Intrinsic Motivation Inventory (IMI) and performance time of the functional tasks.

Results

User acceptance scored highly, with a mean SUS score of at least 63.4 (SD = 19.0) and a mean IMI score of 5.1 points (SD = 0.97 points). Functional task performance improved across repetitions both with and without the glove (p ≤ 0.017), but all functional tasks were performed faster without the glove (p ≤ 0.032).

Conclusion

Participants perceived the iH system as useful, pleasant and meaningful. The learning curve in functional performance time (improvements across repetitions) is promising, since it suggests there is room for improved performance when a longer acquaintance period is applied.

Gender differences in upper extremity motor performance of older persons

BACKGROUND

Motor performance declines with age. Although gender differences in motor strength and speed have been widely reported, the extent to which these differences are maintained in old age has not been well established.

METHODS

Upper extremity motor performance was assessed in 234 men and 530 women Catholic clergy members aged 65 years or older with no clinical evidence of dementia who were participants in the Religious Orders Study. As part of a uniform clinical evaluation, upper extremity motor performance including strength (grip and pinch dynamometry), movement speed including finger tapping and Purdue pegboard and muscle bulk of the arm were collected.

RESULTS

Men were stronger than women at all ages but this difference became less prominent at older ages. Women scored higher on the Purdue Pegboard than men whereas men had faster maximal finger tapping rates than women. Gender differences in speed were not modified by age. Men had greater muscle bulk than women at all ages and these differences were not modified by age. These relationships were not modified by participants with a clinical diagnosis of Parkinson's disease or stroke or by hormone replacement therapy in women.

CONCLUSIONS

Gender differences in upper extremity speed and muscle bulk appear to be relatively stable with increasing age, whereas gender differences in strength were reduced in the oldest old. Longitudinal studies are needed to determine if men and women differ in the rate of decline of strength in old age.

Age and grip strength predict hand dexterity in adults

In the scientific literature, there is much evidence of a relationship between age and dexterity, where increased age is related to slower, less nimble and less smooth, less coordinated and less controlled performances. While some suggest that the relationship is a direct consequence of reduced muscle strength associated to increased age, there is a lack of research that has systematically investigated the relationships between age, strength and hand dexterity. Therefore, the aim of this study was to examine the associations between age, grip strength and dexterity. 107 adults (range 18-93 years) completed a series of hand dexterity tasks (i.e. steadiness, line tracking, aiming, and tapping) and a test of maximal grip strength. We performed three phases of analyses. Firstly, we evaluated the simple relationships between pairs of variables; replicating the existing literature; and found significant relationships of increased age and reduced strength; increased age and reduced dexterity, and; reduced strength and reduced dexterity. Secondly, we used standard Multiple Regression (MR) models to determine which of the age and strength factors accounted for the greater variance in dexterity. The results showed that both age and strength made significant contributions to the data variance, but that age explained more of the variance in steadiness and line tracking dexterity, whereas strength explained more of the variance in aiming and tapping dexterity. In a third phase of analysis, we used MR analyses to show an interaction between age and strength on steadiness hand dexterity. Simple Slopes post-hoc analyses showed that the interaction was explained by the middle to older aged adults showing a relationship between reduced strength and reduced hand steadiness, whereas younger aged adults showed no relationship between strength and steadiness hand dexterity. The results are discussed in terms of how age and grip strength predict different types of hand dexterity in adults.

Short-term testosterone manipulations do not affect cognition or motor function but differentially modulate emotions in young and older male rhesus monkeys

Human aging is characterized by declines in cognition and fine motor function as well as improved emotional regulation. In men, declining levels of testosterone (T) with age have been implicated in the development of these age-related changes. However, studies examining the effects of T replacement on cognition, emotion and fine motor function in older men have not provided consistent results. Rhesus monkeys (Macaca mulatta) are excellent models for human cognitive aging and may provide novel insights on this issue. We tested 10 aged intact male rhesus monkeys (mean age=19, range 15-25) on a battery of cognitive, motor and emotional tasks at baseline and under low or high T experimental conditions. Their performance was compared to that of 6 young males previously tested in the same paradigm (Lacreuse et al., 2009; Lacreuse et al., 2010). Following a 4-week baseline testing period, monkeys were treated with a gonadotropin releasing hormone agonist (Depot Lupron, 200 μg/kg) to suppress endogenous T and were tested on the task battery under a 4-week high T condition (injection of Lupron+T enanthate, 20 mg/kg, n=8) or 4-week low T condition (injection of Lupron+oil vehicle, n=8) before crossing over to the opposite treatment. The cognitive tasks consisted of the Delayed Non-Matching-to-Sample (DNMS), the Delayed Response (DR), and the Delayed Recognition Span Test (spatial-DRST). The emotional tasks included an object Approach-Avoidance task and a task in which monkeys were played videos of unfamiliar conspecifics in different emotional context (Social Playbacks). The fine motor task was the Lifesaver task that required monkeys to remove a Lifesaver candy from rods of different complexity. T manipulations did not significantly affect visual recognition memory, working memory, reference memory or fine motor function at any age. In the Approach-Avoidance task, older monkeys, but not younger monkeys, spent more time in proximity of novel objects in the high T condition relative to the low T condition. In both age groups, high T increased watching time of threatening social stimuli in the Social Playbacks. These results suggest that T affects some aspects of emotional processing but has no effect on fine motor function or cognition in young or older male macaques. It is possible that the duration of T treatment was not long enough to affect cognition or fine motor function or that T levels were too high to improve these outcomes. An alternative explanation for the discrepancies of our findings with some of the cognitive and emotional effects of T reported in rodents and humans may be the use of a chemical castration, which reduced circulating gonadotropins in addition to T. Further studies will investigate whether the luteinizing hormone LH mediates the effects of T on brain function in male primates.

Interactions between brain structure and behavior: the corpus callosum and bimanual coordination

Bimanual coordination skills are required for countless everyday activities, such as typing, preparing food, and driving. The corpus callosum (CC) is the major collection of white matter bundles connecting both hemispheres that enables the coordination between the two sides of the body. Principal evidence for this brain-behavior relationship in humans was first provided by research on callosotomy patients, showing that sectioning (parts of) the CC affected interactions between both hands directly. Later, new noninvasive in vivo imaging techniques, such as diffusion tensor imaging, have energized the study of the link between microstructural properties of the CC and bimanual performance in normal volunteers. Here we discuss the principal factors (such as age, pathology and training) that mediate the relationship between specific bimanual functions and distinct anatomical CC subdivisions. More specifically, the question is whether different bimanual task characteristics can be mapped onto functionally distinct CC subregions. We review the current status of this mapping endeavor, and propose future perspectives to inspire research on this unique link between brain structure and behavior.

Effects of transcranial direct current stimulation in combination with motor practice on dexterous grasping and manipulation in healthy older adults

Abstract Transcranial anodal stimulation (tDCS) over primary motor cortex (M1) improves dexterous manipulation in healthy older adults. However, the beneficial effects of anodal tDCS in combination with motor practice on natural and clinically relevant functional manual tasks, and the associated changes in the digit contact forces are not known. To this end, we studied the effects of 20 min of tDCS applied over M1 for the dominant hand combined with motor practice (MP) in a sham-controlled crossover study. We monitored the forces applied to an object that healthy elderly individuals grasped and manipulated, and their performances on the Grooved Pegboard Test and the Key-slot task. Practice improved performance on the Pegboard test, and anodal tDCS + MP improved retention of this performance gain when tested 35 min later, whereas similar performance gains degraded in the sham group after 35 min. Interestingly, grip force variability on an isometric precision grip task performed with visual feedback of precision force increased following anodal tDCS + MP, but not sham tDCS + MP. This finding suggests that anodal tDCS over M1 might alter the descending drive to spinal motor neurons involved in the performance of isometric precision grip task under visual feedback leading to increased fluctuations in the grip force exerted on the object. Our results demonstrate that anodal stimulation in combination with motor practice helps older adults to retain their improved performance on a functionally relevant manual task in healthy older adults.

Dexterous manipulation is poorer at older ages and is dissociated from decline of hand strength

BACKGROUND

The ability to dynamically control fingertip force vector magnitude and direction is critical for dexterous manipulation. We quantified the dynamic control of fingertip forces to examine how dexterous manipulation declines with age.

METHODS

The strength-dexterity (SD) test measures fingertip forces during compression of a slender spring prone to instability and buckling. The greatest sustained compression (designed to be under 3 N), and force dynamics therein, have been shown to be simple and quick measures of dynamic dexterous manipulation ability. We measured pinch strength and strength-dexterity test in a cross-sectional population of 98 people from 18 to 89 years of age.

RESULTS

Dexterous manipulation ability is poorer at older ages, beginning in middle age (p < .001), with greater decline past 65 years of age. Fingertip force dynamics during spring compression and stabilization show a deterioration of neuromuscular control with age. Importantly, this novel detection of decline in dynamic manipulation ability is not correlated with, and thus cannot be entirely explained by, the known decline in pinch strength. We also measured standardized tests of dexterity in participants older than 45, and discuss how the strength-dexterity test uniquely captures features of sensorimotor capabilities for dexterous manipulation in this adult population.

CONCLUSIONS

Starting in middle age, changes in the functional interactions among sensory, motor, and neural capabilities result in measurably poorer dynamic dexterous manipulation. This deterioration of neuromuscular control motivates and enables future studies to understand the physiological bases for this functional decline so critical to activities of daily living and quality of life.