Validity and reliability of a new clinician-rated tool for freezing of gait severity.

PURPOSE: The Freezing of Gait Severity Tool (FOG Tool) was developed because of limitations in existing assessments. This cross-sectional study investigated its validity and reliability. METHODS: People with Parkinson's disease (PD) were recruited consecutively from clinics. Those who could not walk eight-metres independently (with or without an assistive device), comprehend instructions, or with co-morbidities affecting walking were excluded. Participants completed a set of assessments including the FOG Tool, Timed Up and Go (TUG), and Freezing of Gait Questionnaire. The FOG Tool was repeated and those reporting no medication state change evaluated for test-retest reliability. Validity and reliability were investigated through Spearman's correlations and ICC (two-way, random). McNemar's test was applied to compare the FOG Tool and TUG on the proportion of people with freezing. RESULTS: Thirty-nine participants were recruited [79.5%(n = 31) male; Median(IQR): age-73.0(9.0) years; disease duration-4.0(5.8) years]. Fifteen (38.5%) contributed to test-retest reliability analyses. The FOG Tool demonstrated strongest associations with the Freezing of Gait Questionnaire (ρ = 0.67, 95%CI 0.43-0.83). Test-retest reliability was excellent (ICC = 0.96, 95%CI 0.88-0.99). The FOG Tool had 6.2 times the odds (95%CI 2.4-20.4, p < 0.001) of triggering freezing compared to the TUG. CONCLUSIONS: The FOG Tool appeared adequately valid and reliable in this small sample of people with PD. It was more successful in triggering freezing than the TUG.Implications for RehabilitationThe Freezing of Gait Severity Tool's assessment course is more effective than the commonly-used Timed Up and Go's assessment course for eliciting freezing of gait for clinical evaluation in people with Parkinson's disease.The Freezing of Gait Severity Tool can be considered for scoring freezing of gait severity in people with Parkinson's disease in the clinical setting.

A Wearable, Patient-Adaptive Freezing of Gait Detection System for Biofeedback Cueing in Parkinson's Disease.

Freezing of Gait (FoG) is a common motor-related impairment among Parkinson's disease patients, which substantially reduces their quality of life and puts them at risk of falls. These patients benefit from wearable FoG detection systems that provide timely biofeedback cues and hence help them regain control over their gait. Unfortunately, the systems proposed thus far are bulky and obtrusive when worn. The objective of this paper is to demonstrate the first integration of an FoG detection system into a single sensor node. To achieve such an integration, features with low computational load are selected and dedicated hardware is designed that limits area and memory utilization. Classification is achieved with a neural network that is capable of learning in real time and thus allows the system to adapt to a patient during run-time. A small form factor FPGA implements the feature extraction and classification, whereas a custom PCB integrates the system into a single node. The system fits into a 4.5 × 3.5 × 1.5 cm 3 housing case, weighs 32 g, and achieves 95.6% sensitivity and 90.2% specificity when adapted to a patient. Biofeedback cues are provided either through auditory or somatosensory means and the system can remain operational for longer than 9 h while providing cues. The proposed system is highly competitive in terms of classification performance and excels with respect to wearability and real-time patient adaptivity.

Regression analysis of gait parameters and mobility measures in a healthy cohort for subject-specific normative values.

BACKGROUND: Deviation in gait performance from normative data of healthy cohorts is used to quantify gait ability. However, normative data is influenced by anthropometry and such differences among subjects impede accurate assessment. De-correlation of anthropometry from gait parameters and mobility measures is therefore desirable. METHODS: 87 (42 male) healthy subjects varying form 21 to 84 years of age were assessed on gait parameters (cadence, ankle velocity, stride time, stride length) and mobility measures (the 3-meter/7-meter Timed Up-and-Go, 10-meter Walk Test). Multiple linear regression models were derived for each gait parameter and mobility measure, with anthropometric measurements (age, height, body mass, gender) and self-selected walking speed as independent variables. The resulting models were used to normalize the gait parameters and mobility measures. The normalization's capability in de-correlating data and reducing data dispersion were evaluated. RESULTS: Gait parameters were predominantly influenced by height and walking speed, while mobility measures were affected by age and walking speed. Normalization de-correlated data from anthropometric measurements from |rs| < 0.74 to |rs| < 0.23, and reduced data dispersion by up to 69%. CONCLUSION: Normalization of gait parameters and mobility measures through linear regression models augment the capability to compare subjects with varying anthropometric measurements.

A systematic review of the diagnostic utility of simple tests of change after trial removal of cerebrospinal fluid in adults with normal pressure hydrocephalus.

OBJECTIVE: To synthesize the evidence regarding the diagnostic value of simple ancillary tests post cerebrospinal fluid drainage in normal pressure hydrocephalus. DATA SOURCES: MEDLINE, CINAHL, PsycINFO, Scopus, Web of Science, and Cochrane library databases; last searched on 12 September 2017. REVIEW METHODS: This review was performed applying the steps of the PRISMA statement. The QUADAS 2 tool was used to assess the risk of bias. Prospective and retrospective trials were systematically reviewed, and data on diagnostic accuracy were extracted. Meta-analysis (where possible) was performed. Hierarchical summary receiver operating characteristic package was used to calculate pooled estimates of included diagnostic studies. RESULTS: Seventeen trials (with 812 subjects in total) were identified for inclusion in the meta-analyses for the 18-meter walk test, video-recorded gait performance, cognitive test, and Timed Up and Go Test. The summary estimates of sensitivity and specificity for the 18-meter walk test was 0.83 (95% CI 0.57 to 0.99) and 0.67 (95% CI 0.33 to 0.95), video-recorded gait performance was 0.85 (95% CI 0.47 to 0.99) and 0.68 (95% CI 0.33 to 0.96), cognitive test was 0.82 (95% CI 0.41-0.99) and 0.75 (95% CI 0.39-0.99), and Timed Up and Go Test was 0.89 (95% CI 0.79-0.95) and 0.63 (95% CI 0.24-0.90), respectively. CONCLUSION: This review highlights the diagnostic value of the 18-meter walk test, video-recorded gait performance, cognitive test, and Timed Up and Go Test in predicting shunt outcomes among adults with normal pressure hydrocephalus.