Combining gait and clinical variables could increase the accuracy of identifying cognitive impairment (CI) in geriatric patients. We aimed to classify geriatric patients with and without CI based on clinical variables, gait, or a combination of clinical and gait variables, using two machine learning methods, Random Forest (RF) and Artificial Neural Network (ANN). The most accurate classification model examined how interactions between clinical and gait variables would improve classification accuracy and determine the contributions of key variables. Based on Minimal Mental State Examination (MMSE) scores, 131 geriatric patients were divided into a cognitive impaired and a cognitively healthy (CH) group. From 3D accelerometer data collected during 3 minutes of walking at a habitual speed, we computed 23 dynamic gait variables. In conclusion, an ANN model incorporating the interaction between clinical and gait variables classified geriatric patients with an accuracy of 96%, an area of the receiver operating characteristic curve of 0.95, and a model validation score of 0.97 (F1) based on their clinical status. Machine learning analyses of gait and clinical variables can inform geriatricians about the diagnosis of geriatric patients' cognitive status.
Abstract Background Age-related changes in muscle properties affect daily functioning, therefore a reliable assessment of such properties is required. We examined the effects of age on reliability, muscle quality and interrelation among muscle architecture (MA) parameters of the gastrocnemius medialis (GM), tibialis anterior (TA), and vastus lateralis (VL) muscles. Methods Three raters scored ultrasound (US) scans of 12 healthy younger and older adults, on fascicle length (FL), pennation angle (PA) and muscle thickness (MT). Intra- and inter-rater reliability of MA measures in rest and contraction was assessed by intraclass correlation coefficients (ICC) and standard error of measurements (SEM, SEM%). The relationship between MA parameters was examined using Pearson correlation coefficients. Muscle quality (MQ) was examined using mean pixel intensity. Results Reliability was moderate to excellent for TA in both groups (ICCs: 0.64–0.99, SEM% = 1.6–14.8%), and for VL in the younger group (ICCs: 0.67–0.98, SEM% = 2.0–18.3%). VL reliability was poor to excellent in older adults (ICCs: 0.22–0.99, SEM% = 2.7–36.0%). For GM, ICCs were good to excellent (ICCs: 0.76–0.99) in both groups, but GM SEM% were higher in older adults (SEM% Younger = 1.5–10.7%, SEM% Older = 1.6–28.1%). Muscle quality was on average 19.0% lower in older vs. younger adults. In both groups, moderate to strong correlations were found for VL FL and MT ( r ≥ 0.54), and TA PA and MT ( r ≥ 0.72), while TA FL correlated with MT ( r ≥ 0.67) in younger adults only. Conclusions In conclusion, age- and muscle-specificities were present in the relationships between MT and PA, and MT and FL at rest. Furthermore, the reliability of MA parameters assessed with 2D panoramic US is acceptable. However, the level of reliability varies with age, muscle and MA measure. In older adults notably, the lowest reliability was observed in the VL muscle. Among the MA parameters, MT appears to be the simplest and most easily reproducible parameter in all muscles and age groups.
<b><i>Background/Aims:</i></b> Reliable and valid neuropsychological tests for patients with dementia are scarce. To improve the assessment of attention and inhibitory control in dementia,<i></i> we determined the feasibility, test-retest reliability, and validity of a Flanker task. <b><i>Methods:</i></b> Participants with all-cause diagnosed dementia (<i>n</i> = 22, mean age 84 years; mean Mini-Mental State Examination [MMSE] score = 19.4) performed a computerized Flanker task twice within 7 days. The Flanker task required participants to indicate the direction of target arrows flanked by congruent or incongruent arrows. Number of completed trials, accuracy, and reaction times (RTs) were recorded, and interference scores were calculated from basic scores. We examined the psychometric properties of the Flanker task and its relationship with the MMSE and Stroop test. <b><i>Results:</i></b> The Flanker task was feasible. Test-retest reliability was good for number of correct answers and RTs, and fair to poor for accuracy and the interference scores. The correlation of the Flanker task with Stroop and MMSE performance was fair to poor. <b><i>Conclusion:</i></b> The Flanker task appears to be feasible, and a reliable and valid measure of selective attention. Although the test-retest reliability for the Flanker RT interference measure was fair, future studies need to confirm its validity to measure inhibitory control in patients with dementia.
Abstract Introduction: In human movements muscles lengthen and then shorten, or occasionally shorten and then lengthen, but it is unclear whether the nature of neural activation of the initial phase influences the neural state of the subsequent phase. We examined whether contraction history modulates spinal excitability in the healthy human soleus muscle. Methods : Subjects performed six blocks of 10 repetitions of four muscle actions consisting of specific combinations of passive shortening (PAS), and passive lengthening (PAL), shortening contraction (SHO), and lengthening contraction (LEN); that is: (1) SHO+PAL; (2) PAS+LEN; (3) PAS+PAL; and (4) SHO+LEN. Results : Compared with baseline, the H‐reflex increased in the block of 300–400 s after SHO+PAL and decreased in the block of 0–100 s after PAS+LEN and SHO+LEN. Conclusions : Our results suggest that spinal excitability is potentiated during a muscle action preceded by muscle shortening, but it becomes depressed during a muscle action preceded by muscle lengthening. Muscle Nerve, 2010.
We determined the angular range of motion and the relative timing of displacement in the thorax, lumbar spine, and pelvis in the transverse plane during treadmill walking at three velocities. Nine healthy young females walked on a treadmill for three minutes at 0.40, 0.93, and 1.47 m/s. The position of seven reflective markers and three rigs placed on the thorax, lumbar spine, and pelvis were recorded at 200 Hz by an eight-camera motion capture system. As gait velocity increased, stride length increased, cycle time decreased, and angular displacement in the thorax and L1 decreased but increased at the pelvis and L5 (all P < .05). The time of maximal angular rotation occurred in the following sequence: pelvis, L5, L3, L1, and thorax ( P < .001). The thorax and L1 and L3 were in-phase for shorter duration as gait velocity increased, and this reduction was especially large, approx. 32% ( P < .05), between thorax and pelvis. As gait velocity increased, the pelvis rotated earlier, causing the shortening of in-phase duration between thorax and pelvis. These data suggest that, as gait velocity increases, pelvis rotation dictates trunk rotation in the transverse plane during gait in healthy young females.
