Early functional factors for predicting outcome of independence in daily living after stroke: a decision tree analysis.

OBJECTIVE: This study aimed to investigate the predictive functional factors influencing the acquisition of basic activities of daily living performance abilities during the early stages of stroke rehabilitation using classification and regression analysis trees. METHODS: The clinical data of 289 stroke patients who underwent rehabilitation during hospitalization (164 males; mean age: 62.2 ± 13.9 years) were retrospectively collected and analysed. The follow-up period between admission and discharge was approximately 6 weeks. Medical records, including demographic characteristics and various functional assessments with item scores, were extracted. The modified Barthel Index on discharge served as the target outcome for analysis. A "good outcome" was defined as a modified Barthel Index score ≥ 75 on discharge, while a modified Barthel Index score < 75 was classified as a "poor outcome." RESULTS: Two classification and regression analysis tree models were developed. The first model, predicting activities of daily living outcomes based on early motor functions, achieved an accuracy of 92.4%. Among patients with a "good outcome", 70.9% exhibited (i) ≥ 4 points in the "sitting-to-standing" category in the motor assessment scale and (ii) 32 points on the Berg Balance Scale score. The second model, predicting activities of daily living outcome based on early cognitive functions, achieved an accuracy of 82.7%. Within the "poor outcome" group, 52.2% had (i) ≤ 21 points in the "visuomotor organization" category of Lowenstein Occupational Therapy Cognitive Assessment, (ii) ≤ 1 point in the "time orientation" category of the Mini Mental State Examination. CONCLUSION: The ability to perform "sitting-to-standing" and visuomotor organization functions at the beginning of rehabilitation emerged as the most significant predictors for achieving successful basic activities of daily living on discharge after stroke.

Comparison of biomechanical parameters in lower limb joints of stroke patients according to conventional evaluation scores during level walking.

Objective: Patients with chronic stroke capable of independent gait were classified into functional ambulation category (FAC) 4 or 5, and the kinetic and kinematic data on their lower limb joints on the affected and unaffected sides were compared with that of healthy individuals. Finally, the qualitative changes in the gait of patients with stroke were investigated based on the differences in FAC scores. Methods: Twelve healthy participants and 19 patients with stroke capable of independent gait were included. The three-dimensional (3D) motion analysis and conventional assessment were conducted for all patients with stroke. Results: The FAC 5 group exhibited a larger range of motion (ROM) than the FAC 4 group in knee and hip joints on the affected side and only in the hip on the unaffected side. In the FAC 5 group, ROM differences in the healthy group on either the affected or unaffected side were absent. The peak of the hip flexion moment on the affected side in both the FAC 4 and 5 groups was smaller than that in the healthy group and in the FAC 4 group on the unaffected side. The absorption power minimum on the affected side was smaller only in the FAC 4 group than that in the healthy group and was larger in the FAC 5 group than that in the FAC 4 group. On the unaffected side, the absorption power minimum was smaller only in the FAC 4 group than that in the healthy group. Conclusion: Functional differences in gait were found in patients classified based on conventional evaluation capable of independent gait after post-stroke rehabilitation. Patients may not exhibit complete recovery in the kinetic indices even if they are judged to be normal in the conventional evaluation, and the kinematic gait indices indicate recovery. Evaluating kinetic indices in addition to kinematic indices is necessary, and joint power may be an especially useful index.

Energy absorption at lower limb joints in different foot contact strategies while descending stairs.

BACKGROUND: Joint loads in different walking strategies during stair descent have been investigated in terms of the joint moment in association with the risk of osteoarthritis. However, the absorption mechanisms of the potential energy loss are not known. OBJECTIVE: This study aims to compare the mechanical energy absorptions in lower limb joints in different initial foot contact strategies. METHODS: Nineteen young subjects walked down on instrumented stairs with two different strategies, i.e., forefoot and rearfoot strike. Power and energy at lower limb joints during stance phase were compared between strategies. RESULTS: Lower limb joints absorbed 73 ± 11% of the potential energy released by descending stairs and there was no difference between strategies. Rearfoot strategy absorbed less energy than forefoot strategy at the ankle joint in the 1st phase, which was compensated mainly by more energy absorption at the knee in the 2nd phase and less energy generation at the hip joints in the 3rd phase. CONCLUSION: The results suggest that a leg absorbs most of the potential energy while descending stairs irrespective of the walking strategies and that any reduction of energy absorption at one joint is compensated by other joints. Greater energy absorption at the knee joint compared to the other joints suggests high burden of knee joint muscles and connective tissues during stair-descent, which is even more significant for the rearfoot strike strategy.

Influence of the initial foot contact strategy on knee joint moments during stair and ramp descent.

Gait modification strategies are effective in reducing knee joint loads, which are associated with the development and progression of knee osteoarthritis (OA). However, the effect of modification of the initial foot contact method in high-loading descending task was not investigated. Here, we show that the initial foot contact strategy significantly alters knee joint moments during descending tasks. We found that the second peak flexion moment was lower for the forefoot strike (FFS) than for the rearfoot strike (RFS) in both stair and ramp descent. As for the peak adduction moment, the second peak was lower for the FFS in stair descent, but two peaks were inconsistent in ramp descent. Our results demonstrate that the knee joint loads can be reduced by simple modification of the initial foot contact strategy. In both descending modalities, the FFS may benefit people with early OA in the patellofemoral joint, whose progression is associated with the peak flexion moment. Likewise, the FFS during stair descent may benefit people with early OA in the medial knee, whose progression is associated with the peak adduction moment. The results would be helpful for prevention and rehabilitation programmes of knee OA.

3D Microlithography Using an Integrated System of 5-mm UV-LEDs with a Tilt-Rotational Sample Holder.

This paper demonstrates a 3D microlithography system where an array of 5 mm Ultra Violet-Light Emitting Diode (UV-LED) acts as a light source. The unit of the light source is a UV-LED, which comes with a length of about 8.9 mm and a diameter of 5 mm. The whole light source comprises 20 × 20 matrix of such 5 mm UV-LEDs giving a total number of 400 LEDs which makes it a very favorable source with a large area for having a batch production of the desired microstructures. This light source is able to give a level of precision in microfabrication which cannot be obtained using commercial 3D printers. The whole light source performs continuous rotational movement once it is turned on. This can also move up and down in a vertical direction. This multidirectional light source also comprises a multidirectional sample holder. The light source teaming up with the multidirectional sample holder highly facilitates the process of fabrication of a huge range of 3D structures. This article also describes the different levels of characterization of the system and demonstrates several fabricated 3D microstructures including high aspect ratio vertical micro towers, twisted turbine structures, triangles, inclined pillar 'V' structures, and hollow horn structures as well.

The effect of sitting posture on the loads at cervico-thoracic and lumbosacral joints.

BACKGROUND: The sitting in an awkward posture for a prolonged time may lead to spinal or musculoskeletal disease. It is important to investigate the joint loads at spine while sitting. OBJECTIVE: The purpose of this study was to investigate the joint moment and antero-posterior (AP) reaction force at cervico-thoracic and lumbosacral joint for various sitting postures. METHODS: Twenty healthy males participated in this study. Six sitting postures were defined from three spinal curvatures (slump, flat, and lordosis) and two arm postures (arms-on-chest and arms-forward). Kinematic and kinetic data were measured in six sitting postures from which joint moment and AP reaction force were calculated by inverse dynamics. RESULTS: In the cervico-thoracic joint, joint moment and AP reaction force were greater in slump than the flat and lordosis postures (p< 0.001) and also in arms-forward posture compared to arms-on-chest posture. In the lumbosacral joint, joint moment and AP reaction force were greater in slump than flat and lordotic posture (p< 0.001) but there was no difference between different arm postures. The joint loads (moment and AP reaction force) at the cervico-thoriacic joint were closely related to the head flexion angle (r> 0.86) while those at the lumbosacral joint were correlated to the trunk flexion angle (r> 0.77). In slump posture, the joint moments were close to or over the extreme of the daily life such as sit-to-stand and walking. Consequently, if the slump is continued for a long time, it may cause pain and diseases at the cervico-thoracic and lumbosacral joints. CONCLUSIONS: The results of the study indicated that the lordosis or flat would be better spinal postures. Also, keeping arms close to body would be desirable to reduce joint loads.

A practical method for the detection of freezing of gait in patients with Parkinson's disease.

PURPOSE: Freezing of gait (FOG), increasing the fall risk and limiting the quality of life, is common at the advanced stage of Parkinson's disease, typically in old ages. A simple and unobtrusive FOG detection system with a small calculation load would make a fast presentation of on-demand cueing possible. The purpose of this study was to find a practical FOG detection system. PATIENTS AND METHODS: A sole-mounted sensor system was developed for an unobtrusive measurement of acceleration during gait. Twenty patients with Parkinson's disease participated in this study. A simple and fast time-domain method for the FOG detection was suggested and compared with the conventional frequency-domain method. The parameters used in the FOG detection were optimized for each patient. RESULTS: The calculation load was 1,154 times less in the time-domain method than the conventional method, and the FOG detection performance was comparable between the two domains (P=0.79) and depended on the window length (P<0.01) and dimension of sensor information (P=0.03). CONCLUSION: A minimally constraining sole-mounted sensor system was developed, and the suggested time-domain method showed comparable FOG detection performance to that of the conventional frequency-domain method. Three-dimensional sensor information and 3-4-second window length were desirable. The suggested system is expected to have more practical clinical applications.

Quantitative evaluation of parkinsonian rigidity during intra-operative deep brain stimulation.

This study aims at the quantification of fine change in parkinsonian rigidity at the wrist during deep brain stimulation (DBS) using a portable measurement system and objective mechanical measures. The rigidity of fourteen limbs was evaluated during DBS surgery. The resistive torque to imposed movement was measured for every setting where a reduction in rigidity was perceived by a neurologist. Quantitative mechanical measures derived from experimental data included viscoelastic properties, work, impulse and mechanical impedance. Most mechanical measures could discriminate the optimal setting from baseline (electrode at stereotactic initial position without electrical stimulation) and the highest significance was achieved by viscous damping constant (p<0.001). Spearman correlation coefficients between mechanical measures and clinical score for multiple settings (averaged for 14 limbs) were 0.51-0.77 and the best correlation was shown for viscosity (ρ=0.77 ± 0.22). The results suggest that intraoperative quantification of rigidity during DBS surgery is possible with the suggested system and measures, which would be helpful for the adjustment of electrode position and stimulation parameters.

Analysis of antagonistic co-contractions with motorized passive movement device in patients with Parkinson's disease.

Patients with Parkinson's disease (PD) suffer from an increased resistance to passive movement of a joint, called as rigidity. Stretch reflex and shortening reaction were suggested to be associated to the rigidity, however, the mechanism is still poorly understood. We hypothesized that the co-contraction of antagonistic muscle pairs is enhanced in patients with PD and this induces resistance persisting throughout its range of motion. To test the hypothesis, we developed a motorized device for application of passive movement of the wrist joint and investigated the co-contraction of muscles during passive movement. It consisted of a servo motor connected to a rotating axis with a timing belt, load cell for the measurement of resistance, and other elements for the fixation of arm and hand. Repetitive passive movement was applied to the wrist joint of patients. Co-contraction of antagonistic muscle pairs was significantly greater in patients than in normal subjects (p<0.001), suggesting that the enhanced co-contraction is associated with the mechanical resistance during passive movement, i.e. rigidity. Co-contraction during extended state was greater than the other states (p<0.001), which implies that the length-feedback mechanism may play the important role in co-contraction.

Age-gender differences in the postural sway during squat and stand-up movement.

Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities.

Soft tissue changes after posterior impaction and setback of the maxilla with Le Fort I osteotomy in skeletal class III patients.

The purpose of this retrospective study was to evaluate the changes in the upper lip (UL) by posterior impaction and setback (PI-SB) of the maxilla. The samples consisted of 29 skeletal Class III patients (10 men and 19 women) who received bimaxillary surgery including PI-SB of the maxilla after Le Fort I osteotomy. Lateral cephalograms were taken at 1 week before surgery (T0) and 6 months after surgery (T1). After linear and angular changes of the hard and soft tissue variables were measured, the paired t test, Pearson correlation test, and univariate linear regression analysis were performed for statistical analyses. The changes in the hard tissue landmarks were as follows: ANS, U1E, and U6MBC moved backward (P < 0.001, P < 0.001, and P < 0.05, respectively) and upward (P < 0.001, P < 0.01, and P < 0.001, respectively), whereas A point, U1A, and PNS moved upward only (P < 0.01, P < 0.01, and P < 0.001, respectively). In terms of the soft tissue change, although subnasale (Sn) did not show significant change, pronasale (Pn) moved upward (P < 0.05); UL, backward and downward (all P < 0.001); and Stms (stomodium-superius), backward (P < 0.001). There were significant correlations between the horizontal change of the UL and that of A point and U1E (P < 0.01, P < 0.05). The regression equation of the horizontal change of UL and U1E was [INCREMENT]UL-vertical reference line (VRL) = (0.476 × [INCREMENT]U1E-VRL) - 0.581 (P < 0.05). If U1E moves backward by 3 mm and 5 mm, the UL is predicted to move backward by 0.9 mm and 1.8 mm, respectively. These results might provide a guideline in diagnosis and treatment planning for maxillary surgery with PI-SB.