Relationship between Cognitive Decline and Daily Life Gait among Elderly People Living in the Community: A Preliminary Report.

Introduction: Early detection and intervention are important to prevent dementia. Gait parameters have been recognized as a potentially easy screening tool for mild cognitive impairment (MCI); however, differences in gait parameters between cognitive healthy individuals (CHI) and MCI are small. Daily life gait change may be used to detect cognitive decline earlier. In the present study, we aimed to clarify the relationship between cognitive decline and daily life gait. Methods: We performed 5-Cog function tests and daily life and laboratory-based gait assessments on 155 community-dwelling elderly people (75.5 ± 5.4 years old). Daily life gait was measured for 6 days using an iPod-touch with an accelerometer. Laboratory-based 10-m gait (fast pace) was measured using an electronic portable walkway. Results: The subjects consisted of 98 CHI (63.2%) and 57 cognitive decline individuals (CDI; 36.8%). Daily life maximum gait velocity in the CDI group (113.7 [97.0-128.5] cm/s) was significantly slower than that in the CHI group (121.2 [105.8-134.3] cm/s) (p = 0.032). In the laboratory-based gait, the stride length variability in the CDI group (2.6 [1.8-4.1]) was significantly higher than that in the CHI group (1.8 [1.2-2.7]) (p < 0.001). The maximum gait velocity in daily life gait was weakly but significantly correlated with stride length variability in laboratory-based gait (ρ = -0.260, p = 0.001). Conclusion: We found an association between cognitive decline and slower daily life gait velocity among community-dwelling elderly people.

Association of Activities of Daily Living with Body Weight Change 3 Months After Stroke Onset.

OBJECTIVES: To investigate the relationship between body weight loss and activities of daily living (ADL) 3 months after stroke onset. MATERIALS AND METHODS: This retrospective cohort study included 81 patients at a rehabilitation hospital after receiving acute treatment at our hospital (mean age 70.7 years). Patients were divided into two groups, namely independent and non-independent, based on their ADL 3 months after stroke. Receiver operating characteristic (ROC) curves were constructed with the ADL independence possibility as the objective variable and body weight change rate (%) at 3 months as the explanatory variable. Patients were classified using the weight change rate calculated from the ROC curve and the NIHSS cut-off values, and the ADL independence percentage was compared. RESULTS: The ADL-independent group had significantly lesser body weight loss than the non-independent group (median rate of body weight change: -2.7% vs. -7.2%; p<0.001). The area under the ROC curve was 0.76. The cut-off value was -5.6% for the body weight change rate. When participants with NIHSS ≤ 8 points were selected, the ADL-independent participants' proportion was significantly higher in the body weight loss ≤ -5.6% group than in the > -5.6% group (56.0% vs. 15.4%, p=0.016). However, there was no significant difference in the ADL-independent participants' proportion when those with NIHSS >8 points were selected (p=0.19). CONCLUSIONS: Our findings indicate that weight loss after stroke onset is associated with non-independent ADL at 3 months. Weight maintenance from the onset is important for ADL independence, especially in patients with mild to moderate stroke.

The Relationship between Walking Speed and Step Length in Older Aged Patients.

Compared with elderly people who have not experienced falls, those who have were reported to have a shortened step length, large fluctuations in their pace, and a slow walking speed. The purpose of this study was to elucidate the step length required to maintain a walking speed of 1.0 m/s in patients aged 75 years or older. We measured the 10 m maximum walking speed in patients aged 75 years or older and divided them into the following two groups: Those who could walk 1.0 m/s or faster (fast group) and those who could not (slow group). Step length was determined from the number of steps taken during the 10 m-maximum walking speed test, and the step length-to-height ratio was calculated. Isometric knee extension muscle force (kgf), modified functional reach (cm), and one-leg standing time (s) were also measured. We included 261 patients (average age: 82.1 years, 50.6% men) in this study. The fast group included 119 participants, and the slow group included 142 participants. In a regression logistic analysis, knee extension muscle force (p = 0.03) and step length-to-height ratio (p < 0.01) were determined as factors significantly related to the fast group. As a result of ROC curve analysis, a step length-to-height ratio of 31.0% could discriminate between the two walking speed groups. The results suggest that the step length-to-height ratio required to maintain a walking speed of 1.0 m/s is 31.0% in patients aged 75 years or older.

[The isometric knee extension strength threshold for maintaining walking speed and step length in older male inpatients].

AIM: To clarify the minimum knee extension muscle strength needed to maintain walking speed and step length in older male inpatients. METHOD: The participants were 786 male inpatients of ≥65 years of age without cerebrovascular disorder, orthopedic disease, malignancy, or dementia. We investigated the participants' isometric knee extension muscle force (kgf/kg), maximum walking speed (m/s) and step length, based on their medical records. The relationship of walking speed and step length to isometric knee extension muscle force was fitted to linear and nonlinear models, and the respective R2 values were compared. Next, the muscle force data were divided into two groups, and two linear functions were calculated. Then, the muscle force value that minimized the sum of the residual sum of squares of the two linear function expressions was obtained. RESULTS: The R2 values of each equation in the nonlinear model were higher than those in the linear model. Among all participants, the muscle force values that minimized the sum of the residual sum of squares for walking speed and step length were 0.33 kgf/kg and 0.43 kgf/kg, respectively. Among participants of ≤74 years of age, the muscle force value that minimized the sum of the residual sum of squares was 0.30 kgf/kg for both walking speed and step length, whereas the values were 0.32 kgf/kg and 0.43 kgf/kg, respectively, in participants of ≥75 years of age. CONCLUSION: Walking speed and step length were significantly decreased in male inpatients of 65-74 years of age when the isometric knee extension force values for both were <0.30 kgf/kg. In contrast, among male inpatients of ≥75 years of age, these values were significantly decreased when the respective isometric knee extension muscle force values were <0.32 kgf/kg and <0.43 kgf/kg.

Predicting recovery of cognitive function soon after stroke: differential modeling of logarithmic and linear regression.

Cognitive disorders in the acute stage of stroke are common and are important independent predictors of adverse outcome in the long term. Despite the impact of cognitive disorders on both patients and their families, it is still difficult to predict the extent or duration of cognitive impairments. The objective of the present study was, therefore, to provide data on predicting the recovery of cognitive function soon after stroke by differential modeling with logarithmic and linear regression. This study included two rounds of data collection comprising 57 stroke patients enrolled in the first round for the purpose of identifying the time course of cognitive recovery in the early-phase group data, and 43 stroke patients in the second round for the purpose of ensuring that the correlation of the early-phase group data applied to the prediction of each individual's degree of cognitive recovery. In the first round, Mini-Mental State Examination (MMSE) scores were assessed 3 times during hospitalization, and the scores were regressed on the logarithm and linear of time. In the second round, calculations of MMSE scores were made for the first two scoring times after admission to tailor the structures of logarithmic and linear regression formulae to fit an individual's degree of functional recovery. The time course of early-phase recovery for cognitive functions resembled both logarithmic and linear functions. However, MMSE scores sampled at two baseline points based on logarithmic regression modeling could estimate prediction of cognitive recovery more accurately than could linear regression modeling (logarithmic modeling, R(2) = 0.676, P<0.0001; linear regression modeling, R(2) = 0.598, P<0.0001). Logarithmic modeling based on MMSE scores could accurately predict the recovery of cognitive function soon after the occurrence of stroke. This logarithmic modeling with mathematical procedures is simple enough to be adopted in daily clinical practice.

The relationship between knee extension strength and lower extremity functions in nursing home residents with dementia.

PURPOSE: To assess the relationships between knee extension strengths and lower extremity functions in subjects with dementia and to predict lower extremity functions using knee extension strength. METHODS: Fifty-four nursing home residents with dementia were enrolled in the study. The strength of the knee extensor was measured using a hand-held dynamometer. To predict lower extremity functions, subjects were classified into two groups: those who could dress their lower body, toilet, transfer to bed/toilet/shower and walk independently, and those who required assistance. Knee extension strength was compared between the two groups. RESULTS: Logistic regression analysis showed that the strength of the knee extensor muscles was a significant predictor of the ability to dress the lower body (odds ratio, 109.90; 95% CI, 7.60-1589.49), toileting (odds ratio, 18.29; 95% CI, 2.41-138.84), transferring to bed/toilet/shower (odds ratio, 39.70; 95% CI, 4.51-349.08), and gait performance (odds ratio, 12.77; 95% CI, 2.30-70.77). The curve of the negative and positive predictive values indicated that a cutoff score of 0.8 Nm/kg would provide the best balance for dressing the lower body and toileting; 1.2 Nm/kg for transferring to bed/toilet/shower; and 0.6 Nm/kg for gait performance. CONCLUSIONS: Knee extension strength was significantly related to the lower extremity functions in people with dementia. Moreover, threshold levels of strength existed that could predict lower extremity dysfunctions in people with dementia.

Predicting recovery of bilateral upper extremity muscle strength after stroke.

OBJECTIVE: To investigate the recovery pattern of bilateral upper extremity muscle strength and to predict the recovery of strength early after stroke using a logarithmic regression model. DESIGN: Longitudinal study. SUBJECTS: Twenty-one inpatients with post-stroke hemiparesis were enrolled. The mean time after stroke event was 7.1 days (standard deviation (SD) 3.5 days). METHODS: Bilateral elbow flexion and extension strengths were assessed separately with a hand-held dynamometer.Grip strength was also assessed with a Jamar dynamometer.These measurements were carried out on 4 occasions: baseline assessment within 2 weeks following stroke onset, and at weeks 1, 2 and 3 following baseline evaluation. Recovery off lexion and extension strengths was predicted using a logarithmic model using scores at the initial 2 evaluations. RESULTS: The time course of recovery for bilateral upper extremities resembled a logarithmic function. Moreover, on the basis of a logarithmic regression model, baseline measures of bilateral strengths sampled from 2 time-points during recovery could be applied to predict the pattern of recovery accurately during the subacute stroke phase (R(2) = 0.74­0.95,p < 0.0001). CONCLUSION: Upper extremity muscle strength improved significantly in a similar pattern on the sides contralateral and ipsilateral to the brain lesion. Moreover, a logarithmic regression model accurately predicted both measures.

Reliability and validity of measurements of knee extension strength obtained from nursing home residents with dementia.

OBJECTIVE: To describe the reliability of strength measurement by hand-held dynamometer and to identify the prediction of gait and stand-up ability by the strength measurement in people with dementia. DESIGN: Correlational study in which 60 persons with Alzheimer disease were enrolled. The strength of knee extensor was measured twice separated by a 3-min interval using a hand-held dynamometer. The presence or absence of impaired gait and sit-to-stand was also determined. RESULTS: Intraclass correlation coefficient was 0.97. Bland-Altman plots showed the distribution of test-retest differences in the subjects with Mini-Mental State Examination score of 10 points or fewer, increased with isometric knee extensor strength. Logistic regression analysis showed strength of the knee extensor muscles to be a significant predictor of gait performance (odds ratio, 443.0; 95% confidence interval, 9.20-21325.7) and sit-to-stand performance (odds ratio, 47.32; 95% confidence interval, 3.31-675.8). CONCLUSIONS: The strength measurement with a hand-held dynamometer was reliable in people with dementia. Furthermore, normalized knee extensor strength was indicated to be a significant predictor of gait and sit-to-stand performance. However, caution is needed when interpreting the result of strength measurement when it is carried out on subjects with a Mini-Mental State Examination score of 10 points or fewer and with a high strength level.