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Grasp force control in older adults.

Diminished tactile sensibility and impaired hand dexterity have been reported for elderly individuals. Reports that younger adults with severely impaired tactile sensibility use excessive grasp force during routine grasp and manipulation tasks raise the possibility that elderly persons likewise produce large grasp forces that may contribute to impaired dexterity. Impaired pseudomotor functioning also occurs in elderly subjects and may yield a slipperier skin surface that enhances the possibility for excessive grasp force. The present study measured grasp force in 10 elderly and 9 young adult individuals, during grasp and vertical lift of a small object, using a precision (pinch) grip of the thumb and index finger. The slipperiness of the object's gripped surfaces was unexpectedly varied. Skin slipperiness was estimated by also measuring the grasp force at which the object slipped from grasp. The older subjects employed grasp forces that were, on average, twice as large as those of the young subjects, with some producing forces many times greater than the young subjects' average grip force. Grip forces also were significantly more variable across trials in older subjects. This increased variability was not caused simply by the elderly subjects' increased grip force. A portion of the increased force was due to increased skin slipperiness. The grip force that the elderly subjects produced in excess of the slip force (the "margin of safety" against object slippage) was larger than would have been predicted from their skin slipperiness, however. It is suggested that, in part, the excessive grasp forces represent a strategic response to tactile sensibility impairment. Twopoint discrimination limina in the older subjects averaged about four times greater than in the younger subjects. Increased grasp forces in elderly persons may result from other factors, such as increased variability in grip force production. The contributions of excessive grasp forces to impaired dexterity in older persons still need to be addressed experimentally.

Journal Article↗

Daily activities and hand function in women with scleroderma.

OBJECTIVE: To give a detailed description of hand function and the ability to perform daily activities among patients with systemic sclerosis. METHODS: Thirty patients with scleroderma answered a self-administered activities of daily living (ADL) questionnaire. Hand function was estimated with respect to hand mobility, dexterity, and grip force. Perceived symptoms were reported on a visual analogue scale (VAS), and skin thickness was assessed by means of the modified Rodnan skin score. RESULTS: Finger flexion and extension were the most impaired aspects of hand mobility. Dexterity was on average reduced to 68-80%, and grip force to 46-65% compared with values for healthy persons. The predominant self-perceived problem was Raynaud's phenomenon, whereas pitting scars/ulcers were perceived as the least problem. Activities building on hand and arm function were harder to perform than activities depending on lower limb function. Raynaud's phenomenon, stiffness, grip force, and dexterity were factors with the strongest associations with ADL difficulties. Assistive devices and alternative working methods improved ADL ability. CONCLUSION: Impaired hand function was related to ADL difficulties and the use of assistive devices improved ADL. This emphasizes the importance of treatments that improve hand function and of testing ergonomic tools.

Activities of Daily Living↗

Macrophage inflammatory protein 1 alpha, interleukin 3 and diffusible marrow stromal factors maintain human hematopoietic stem cells for at least eight weeks in vitro.

Factors that induce proliferation of the human hematopoietic stem cell are ill-defined. Primitive hematopoietic progenitors can be maintained and differentiate in stroma-dependent, long-term bone marrow cultures (LTBMC), originally described by Dexter et al. (Dexter, T. M., L. H. Coutinho, E. Spooncer, C. M. Heyworth, C. P. Daniel, R. Schiro, J. Chang, and T. D. Allen. 1990. Molecular Control of Haemopoiesis). However, 70-80% of primitive progenitors capable of reinitiating secondary stromal cultures (LTBMC-initiating cells [IC]) are lost over a period of 5 wk in such cultures. We have recently described a novel "stroma-noncontact" culture system, in which hematopoietic progenitors are separated from the stromal layer by a 0.4-micron microporous filter membrane. Primitive progenitors in such cultures can not only differentiate into committed progenitors, but are also maintained to a greater extent than in "Dexter" cultures. However, still only 50% of the originally seeded LTBMC-IC are recovered at week 5. Since maintenance of primitive progenitors may depend not only on growth-promoting factors but also on factors that inhibit differentiation and/or proliferation, we evaluated the effect of macrophage inflammatory protein 1 alpha (MIP-1 alpha) or "stem cell inhibitor" in combination with the growth-inducing factor interleukin 3 (IL-3) on the recovery of LTBMC-IC from stroma-noncontact cultures. We demonstrate that addition of MIP-1 alpha alone to stroma-noncontact cultures does not change the number of LTBMC-IC present after 8 wk, indicating that this factor may not directly inhibit or stimulate proliferation of primitive progenitors. Addition of the growth stimulatory cytokine, IL-3, alone results in exhaustion of LTBMC-IC after 8 wk of culture, possibly as a result of their terminal differentiation. However, LTBMC-IC can be maintained for at least 8 wk when grown in stroma-noncontact cultures supplemented with both MIP-1 alpha plus IL-3. This effect depends on soluble (ill-defined) stromal factors, and results from a direct interaction of these cytokines with the progenitor population or its progeny, but not the stroma.

Bone Marrow↗

Validation of cutaneous pressure threshold measurements for the evaluation of hand function.

The relationship of measures of pressure perception to hand function was evaluated by correlating the results of the Mayo Dexterity Test and a timed object recognition test with the one- and two-point static and moving touch thresholds for the index finger pulp of 44 hands. The Mayo Dexterity Test permits the use of vision, while the object recognition test does not. Quantitative sensory testing was done with the Pressure-specifying Sensory Device. Cutaneous pressure threshold measurements with this device had a statistically significant correlation with the small-object subset of the Mayo Dexterity Test (p < 0.006) and with the object recognition test (p < 0.001), demonstrating that the Pressure-specifying Sensory Device is a valid tool for evaluating the sensory aspect of hand function.

Adolescent↗

The effects of glyceryl trinitrate and nicotinic acid ointments during cold exposure.

The aim of the present experimental study was to examine the effects of local application of glyceryl trinitrate and nicotinic acid on the cold-provoked haemodynamic responses, pain and hand dexterity. Ten young healthy volunteers participated in this randomized, cross-over study with three phases at least two days apart. Five cm of 2% glyceryl trinitrate ointment, 10% nicotinic acid ointment or placebo ointment was applied on the back of each subject's both hands 15 min. before the 7 min. cold exposure. Blood pressure and heart rate were measured prior to, during and after the cold exposure. In addition, the effect of cold on hand dexterity was evaluated by the Purdue pegboard test and the subjects assessed the pain in their hands during the cold exposure. Pretreatment with glyceryl trinitrate ointment counteracted the cold-induced haemodynamic response, as evidenced by a significantly (P < 0.05) smaller mean increase in the systolic blood pressure from the baseline compared with placebo. In contrast, the cold-induced increase in the systolic blood pressure observed after pretreatment with nicotinic acid ointment did not differ from placebo. Both glyceryl trinitrate and nicotinic acid alleviated the cold-induced pain, but neither of them prevented the deterioration of hand dexterity. In conclusion, the haemodynamic response provoked by a brief cold exposure could to some extent be counteracted by pretreatment with glyceryl trinitrate ointment, but not with nicotinic acid ointment, compared with placebo.

Administration, Topical↗

Validation of the ABILHAND questionnaire as a measure of manual ability in patients with rheumatoid arthritis.

OBJECTIVE: Hand and upper limb involvement is common in patients with rheumatoid arthritis (RA). However, its impact on manual activities of daily life has not been fully evaluated. A measure of manual ability was developed, through the Rasch measurement model, by adapting and validating the ABILHAND questionnaire, which measures the patient's perceived difficulty in performing everyday manual activities. METHODS: 112 patients with RA were evaluated. The following tests were performed: the ABILHAND questionnaire, the Health Assessment Questionnaire (HAQ), the Jamar grip and key pinch strength tests, the Box and Block dexterity test and the Purdue pegboard dexterity test. In total, 35 patients were reassessed to determine the test-retest reliability of the ABILHAND, and 6 patients were studied before and after therapy with tumour necrosis factor (TNF) blockers to address sensitivity to change. RESULTS: The Rasch refinement of the ABILHAND led to a selection of 27 items rated on a 3-point scale. The resulting ability scale was targeted to the ability of the patients. The item-difficulty hierarchy was stable across demographic and clinical subgroups and over time. Grip and key pinch strength and manual and digital dexterity on both hands were significantly, though moderately, correlated with the ABILHAND measures. Manual ability was also significantly related to the number of affected hands, disease duration, tender and swollen joint counts on upper limbs, disease activity and the HAQ. Sensitivity to change was demonstrated in patients treated with TNF blockers, commensurate with their clinical improvement. CONCLUSION: The ABILHAND questionnaire is a clinically valid person-centred measure of manual ability that could be useful in longitudinal RA studies.

Activities of Daily Living↗

Effects of augmented exercise therapy time after stroke: a meta-analysis.

BACKGROUND AND PURPOSE: To present a systematic review of studies that addresses the effects of intensity of augmented exercise therapy time (AETT) on activities of daily living (ADL), walking, and dexterity in patients with stroke. SUMMARY OF REVIEW: A database of articles published from 1966 to November 2003 was compiled from MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, PEDro, DARE, and PiCarta using combinations of the following key words: stroke, cerebrovascular disorders, physical therapy, physiotherapy, occupational therapy, exercise therapy, rehabilitation, intensity, dose-response relationship, effectiveness, and randomized controlled trial. References presented in relevant publications were examined as well as abstracts in proceedings. Studies that satisfied the following selection criteria were included: (1) patients had a diagnosis of stroke; (2) effects of intensity of exercise training were investigated; and (3) design of the study was a randomized controlled trial (RCT). For each outcome measure, the estimated effect size (ES) and the summary effect size (SES) expressed in standard deviation units (SDU) were calculated for ADL, walking speed, and dexterity using fixed and random effect models. Correlation coefficients were calculated between observed individual effect sizes on ADL of each study, additional time spent on exercise training, and methodological quality. Cumulative meta-analyses (random effects model) adjusted for the difference in treatment intensity in each study was used for the trials evaluating the effects of AETT provided. Twenty of the 31 candidate studies, involving 2686 stroke patients, were included in the synthesis. The methodological quality ranged from 2 to 10 out of the maximum score of 14 points. The meta-analysis resulted in a small but statistically significant SES with regard to ADL measured at the end of the intervention phase. Further analysis showed a significant homogeneous SES for 17 studies that investigated effects of increased exercise intensity within the first 6 months after stroke. No significant SES was observed for the 3 studies conducted in the chronic phase. Cumulative meta-analysis strongly suggests that at least a 16-hour difference in treatment time between experimental and control groups provided in the first 6 months after stroke is needed to obtain significant differences in ADL. A significant SES supporting a higher intensity was also observed for instrumental ADL and walking speed, whereas no significant SES was found for dexterity. CONCLUSIONS: The results of the present research synthesis support the hypothesis that augmented exercise therapy has a small but favorable effect on ADL, particularly if therapy input is augmented at least 16 hours within the first 6 months after stroke. This meta-analysis also suggests that clinically relevant treatment effects may be achieved on instrumental ADL and gait speed.

Activities of Daily Living↗

Neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery with cardiopulmonary bypass: a randomized trial.

BACKGROUND: Neuropsychological deficits occur in 30% to 80% of patients undergoing heart surgery and are due in part to ischemic cerebral injury during cardiopulmonary bypass. We tested whether mild hypothermia, the most efficacious neuroprotective strategy found in laboratory studies, improved cognitive outcome in patients undergoing coronary artery surgery. METHODS AND RESULTS: Patients 60 years or older scheduled for coronary artery surgery were enrolled. During cardiopulmonary bypass, patients were initially cooled to 32 degrees C then randomly assigned to rewarming to 37 degrees C (control) or 34 degrees C (hypothermic), with no further intraoperative warming. Testing was scheduled preoperatively and 1 week and 3 months postoperatively. Eleven tests were combined into 3 cognitive domains: memory, attention, and psychomotor speed and dexterity. A patient was classified as having a cognitive deficit if a decrease of >/=0.50 SD was realized in 1 or more domains. The incidence of cognitive deficits 1 week after surgery, which was the primary outcome, was 62% () in the control group and 48% () in the hypothermic group (relative risk 0.77, P=0.048). In the hypothermic group, the magnitude of deterioration in attention and in speed and dexterity was reduced by 55.6% (P=0.038) and 41.3% (P=0.042), respectively. At 3 months, the hypothermic group still performed better on one test of speed and dexterity (grooved pegboard). There was no difference in morbidity or mortality. CONCLUSIONS: Our findings support a neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery and should encourage physicians and perfusionists to pay careful attention to brain temperature during cardiopulmonary bypass.

Aged↗

Reduction of the hand representation in the ipsilateral primary motor cortex following unilateral section of the corticospinal tract at cervical level in monkeys.

BACKGROUND: After sub-total hemi-section of cervical cord at level C7/C8 in monkeys, the ipsilesional hand exhibited a paralysis for a couple of weeks, followed by incomplete recovery of manual dexterity, reaching a plateau after 40-50 days. Recently, we demonstrated that the level of the plateau was related to the size of the lesion and that progressive plastic changes of the motor map in the contralesional motor cortex, particularly the hand representation, took place following a comparable time course. The goal of the present study was to assess, in three macaque monkeys, whether the hand representation in the ipsilesional primary motor cortex (M1) was also affected by the cervical hemi-section. RESULTS: Unexpectedly, based on the minor contribution of the ipsilesional hemisphere to the transected corticospinal (CS) tract, a considerable reduction of the hand representation was also observed in the ipsilesional M1. Mapping control experiments ruled out the possibility that changes of motor maps are due to variability of the intracortical microstimulation mapping technique. The extent of the size reduction of the hand area was nearly as large as in the contralesional hemisphere in two of the three monkeys. In the third monkey, it represented a reduction by a factor of half the change observed in the contralesional hemisphere. Although the hand representation was modified in the ipsilesional hemisphere, such changes were not correlated with a contribution of this hemisphere to the incomplete recovery of the manual dexterity for the hand affected by the lesion, as demonstrated by reversible inactivation experiments (in contrast to the contralesional hemisphere). Moreover, despite the size reduction of M1 hand area in the ipsilesional hemisphere, no deficit of manual dexterity for the hand opposite to the cervical hemi-section was detected. CONCLUSION: After cervical hemi-section, the ipsilesional motor cortex exhibited substantial reduction of the hand representation, whose extent did not match the small number of axotomized CS neurons. We hypothesized that the paradoxical reduction of hand representation in the ipsilesional hemisphere is secondary to the changes taking place in the contralesional hemisphere, possibly corresponding to postural adjustments and/or re-establishing a balance between the two hemispheres.

Animals↗

Cognitive and motor function in people with multiple sclerosis in Stockholm County.

The aim of this study was to analyse cognitive and motor function in a population-based sample of people with multiple sclerosis (PwMS), taking into account both disease-related data and sociodemographic factors. Data were collected from 166 PwMS during home visits. Cognitive function was assessed by the Mini-Mental State Examination (MMSE), the Free Recall and Recognition of 12 Random Words Test (FRR12RWT), and the Symbol Digit Modalities Test (SDMT); manual dexterity by the Nine-Hole Peg Test (NHPT); global motor capacity by the Lindmark Motor Capacity Assessment; and walking capacity by a timed 10-metre walk. On cognitive tests, 55% (MMSE), 84% (FRR12RWT), and 45% (SDMT) of PwMS scored within the normal range; 27% of PwMS displayed normal manual dexterity, 9% had a maximal motorcapacity score, and 8% walked at normal speed. Factors associated with normal cognitive function were lower disability and higher education; lower disability and current employment were predictive of capacity to perform the NHPT and to walk 10 metres. In conclusion, cognitive function was normal in approximately half of the PwMS investigated, while a minority displayed normal manual dexterity and normal walking capacity. Thus, both disease severity and sociodemographic factors appear to influence cognitive and motor function in MS.

Activities of Daily Living↗

Cell processing engineering for ex-vivo expansion of hematopoietic cells.

The cell processing engineering for ex vivo expansion of hematopoietic cells is reviewed. All hematopoietic cells of different lineages and/or at various stages of differentiation are derived from the same precursor, pluripotent hematopoietic stem cells. Bone marrow stromal cells promote and regulate the self-renewal, commitment, differentiation, and proliferation of stem cells and progenitors through their secreted extracellular matrices and cytokine environment in the hematopoietic microenvironment. Although stroma-mediated hematopoiesis has been studied in vitro using the Dexter culture system in tissue culture flasks, hematopoiesis in the Dexter culture system is almost limited to a granulocyte lineage and the system could not expand primitive cells. The addition of large amounts of cytokines to the culture of hematopoietic cells enabled their expansion, but is too expensive. Some clonal stromal cell lines have been established from the Dexter culture of murine bone marrow cells in order to simplify and stimulate the ex vivo expansion of hematopoietic cells. In order to solve the problem regarding the usage of exogeneic stromal cell lines, a novel membrane-separated coculture system, in which stromal cells adhere onto the lower surface of a porous membrane and hematopoietic cells are incubated on the upper surface of the membrane, was proposed. In order to mimic the contact between stromal and hematopoietic cells in vivo in the bone marrow, several types of three-dimensional (3-D) culture of hematopoietic cells were developed. The 3-D coculture of hematopoietic cells with spatial development of stromal cells in nonwoven fabrics enabled the expansion of progenitors without cytokine addition. Progenitors in cord blood mononucleated cells were also successfully expanded without the addition in the 3-D coculture with primary human bone marrow stromal cells in 3-D. Heparin addition to the 3-D coculture and coating the nonwoven fabrics with N-(O-beta-(6-O-sulfogalactopyranosyl)-6-oxyhexyl)-3,5-bis(dodecyloxy)-benzamide further increased the number of progenitors.

Animals↗

Normative and validation studies of the Nine-hole Peg Test with children.

This study evaluated norms for fine motor dexterity skills on elementary school children of ages 5 through 10 and conducted reliability and validity stud ies utilizing the Nine-hole Peg Test. The sample included 826 students in 10 elementary schools. Moderately high test-retest reliability (rs = .81 and .79) and high interrater agreement (rs > .99) were obtained. Older students had shorter completion time that measured fine motor dexterity than younger students. Significant sex differences were found in completion time, but only for the dominant hand. Correlations of -.80 and -.74 between the scores on the Nine hole Peg Test and Purdue Pegboard Test at all tested ages indicated adequate concurrent validity of the measures and a significant difference in test scores between regular and special education groups provided further evidence of construct validity. The findings supported the Nine-hole Peg Test as an effective screening tool for fine motor dexterity of school-age children.

Child↗

The Purdue Pegboard Test: normative data for people aged 60 and over.

Manual dexterity is frequently evaluated in rehabilitation services to estimate hand function. Several tests have been developed for this purpose, including the Purdue Pegboard, which measures fine manual dexterity. The goals of the study were to verify the test-retest reliability with subjects aged 60 and over without upper limb impairment, and to develop normative data based on a random sample of healthy older community-living individuals. The results show that the test-retest reliability is good (intra-class correlation coefficients from 0.66 to 0.90, depending on the subtest). Norms are presented to help clinicians involved in rehabilitation services to better differentiate real dexterity deficits from those that may be attributed to normal ageing.

Aged↗

On the design of robotic hands for brain-machine interface.

Brain-machine interface (BMI) is the latest solution to a lack of control for paralyzed or prosthetic limbs. In this paper the authors focus on the design of anatomical robotic hands that use BMI as a critical intervention in restorative neurosurgery and they justify the requirement for lower-level neuromusculoskeletal details (relating to biomechanics, muscles, peripheral nerves, and some aspects of the spinal cord) in both mechanical and control systems. A person uses his or her hands for intimate contact and dexterous interactions with objects that require the user to control not only the finger endpoint locations but also the forces and the stiffness of the fingers. To recreate all of these human properties in a robotic hand, the most direct and perhaps the optimal approach is to duplicate the anatomical musculoskeletal structure. When a prosthetic hand is anatomically correct, the input to the device can come from the same neural signals that used to arrive at the muscles in the original hand. The more similar the mechanical structure of a prosthetic hand is to a human hand, the less learning time is required for the user to recreate dexterous behavior. In addition, removing some of the nonlinearity from the relationship between the cortical signals and the finger movements into the peripheral controls and hardware vastly simplifies the needed BMI algorithms. (Nonlinearity refers to a system of equations in which effects are not proportional to their causes. Such a system could be difficult or impossible to model.) Finally, if a prosthetic hand can be built so that it is anatomically correct, subcomponents could be integrated back into remaining portions of the user's hand at any transitional locations. In the near future, anatomically correct prosthetic hands could be used in restorative neurosurgery to satisfy the user's needs for both aesthetics and ease of control while also providing the highest possible degree of dexterity.

Brain↗

[Veterinary surgery education performed on models]

At the Veterinary Surgery Clinic of the University of Zurich models were developed in cooperation with a surgery professor from the United States. These models allow to practice manual dexterity of the students in basic surgical techniques. Additionally, proper assisting in these basic surgical techniques can also be practiced using these models. A further advantage represents the facts that these models do not have a scent because they are manufactured from a special polyurethane facilitating easy transport of these models to allow additional practicing at the students leisure at home. The result of this education, which was initiated three years ago, is better manual dexterity in surgical techniques, a dexterity which is achieved without sacrificing laboratory animals. This represents a big advantage for the students and later the veterinarian.

Journal Article↗

Correlates for end-stage renal disease patients.

In this study 112 end-stage renal disease patients on hemodialysis were analyzed for their state of well-being, cognition, ambulatory capacity, and dexterity. The Nottingham Health Profile, the locomotion and dexterity sections of the Office of Population Censuses and Surveys disability scale, the modified Mini Mental State examination and a weighted index of comorbidity were used for assessment. The study revealed that good cognition, good mood, young age, and milder comorbid conditions were positively linked with good functional levels of locomotion and dexterity. The test instruments used in the investigation were considered simple to use and were effective in revealing relationships between the above-mentioned parameters.

Adaptation, Psychological↗

Mechanical design of a shape memory alloy actuated prosthetic hand.

This paper presents the mechanical design for a new five fingered, twenty degree-of-freedom dexterous hand patterned after human anatomy and actuated by Shape Memory Alloy artificial muscles. Two experimental prototypes of a finger, one fabricated by traditional means and another fabricated by rapid prototyping techniques, are described and used to evaluate the design. An important aspect of the Rapid Prototype technique used here is that this multi-articulated hand will be fabricated in one step, without requiring assembly, while maintaining its desired mobility. The use of Shape Memory Alloy actuators combined with the rapid fabrication of the non-assembly type hand, reduce considerably its weight and fabrication time. Therefore, the focus of this paper is the mechanical design of a dexterous hand that combines Rapid Prototype techniques and smart actuators. The type of robotic hand described in this paper can be utilized for applications requiring low weight, compactness, and dexterity such as prosthetic devices, space and planetary exploration.

Alloys↗

Using electrodiagnostic machine to study movement rhythm variation.

BACKGROUND: Hand movement constitutes the most common daily activities in our life. Hand dexterity is often impaired in patients with neurological disease. We developed an adjunct method, based upon the electrodiagnostic software, for study of motor control and hand dexterity. METHODS: Thirty-two normal subjects, 2 stroke patients and 2 Parkinson patients were included in the study. All of them were right-handed, and were asked to pace rhythmic finger tapping at a comfortable rate without cue or any external stimuli. A trigger kit was designed to transform the finger tapping. After using the triggering mode and adjusting the sweep speed, 2 tapping signals were simultaneously displayed on the screen. The first signal was the triggering potential, and the variation in timing of the second signal represented the variation in timing of the inter-response interval. Twenty sweeps were recorded, superimposed and measured on the screen. Movement rhythm variation (MRV) was defined as b/a x 100 (b = [maximal interval of finger tapping - minimal interval of finger tapping]; a = [maximal interval of finger tapping + minimal interval of finger tapping]/2). Each subject started with right hand and then left hand. RESULTS: MRV measurement showed excellent intrarater (r = 0.97) and interrater (r = 0.97) reliability. In normal right-handed subjects, the MRV was better in right hand than in left hand (right 16.5 +/- 4.1% and left 21.0 +/- 7.6%; p < 0.05). The MRV improved in stroke patients along with the recovery and improved in Parkinson patients after levodopa treatment. CONCLUSIONS: MRV was a good method to provide quantitative data for assessment of hand dexterity. Our study also showed the potential role of MRV in motor control study.

Adult↗