The Minimal Clinically Relevant Change of the FOG Score

Reliability and variability of physiotherapists scoring freezing of gait through video analysis

BACKGROUND

The "gold standard" marker for freezing of gait severity is percentage of time spent with freezing observed through video analysis.

OBJECTIVE

This study examined inter- and intra-rater reliability and variability of physiotherapists rating freezing of gait severity through video analysis and explored the effects of experience.

METHODS

Thirty physiotherapists rated 14 videos of Timed Up and Go performance by people with Parkinson's and gait freezing. Ten videos were unique, while four were repeated. Freezing frequency, total duration, and percentage of time spent with freezing were computed. Reliability and variability were estimated using ICC (2,1) and mean absolute differences. Between-group differences were calculated with the one-way ANOVA.

RESULTS

Inter- and intra-rater reliability ranged from moderate to good (ICC: inter-rater frequency = 0.63, duration = 0.78, percentage = 0.50; intra-rater frequency = 0.84, duration = 0.89, percentage = 0.50). Variability for freezing frequency was two episodes. Inter- and intra-rater variability for total freezing duration was 18.8 and 12.3  seconds, respectively. For percentage of time spent with freezing, this was 15.2% and 13.5%. Physiotherapy experience had no effect.

CONCLUSION

Physiotherapists demonstrated sufficient reliability, but variability was large enough to cause changes in severity classifications on existing rating scales. Percentage of time spent with freezing was the least reliable marker, supporting the use of freezing frequency or total duration instead.

Randomized crossover trial on motor and non-motor outcome of directional deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) with electric field steering may avoid areas responsible for side effects. This prospective randomized cross-over trial compared omnidirectional (OS) and directional (DS) subthalamic DBS in 19 patients. Electromyographically measured rigidity was the primary outcome. Motor and non-motor scores were secondary outcomes. There were no significant differences between OS and DS. In the acute setting, both conditions improved motor scores compared to no stimulation. Motor symptoms improved after 3 weeks of OS relative to acute measurements, whereas they worsened under DS. The more ventral the active contact, and the less the motor improvement sweet spot was stimulated, the greater the benefit of DS over OS for executive function. Accurate OS of the dorsal subthalamic nucleus ensures motor and non-motor improvements. While DS can mitigate executive decline stemming from off-target stimulation, it may lead to worse motor outcomes. Larger, long-term studies are needed to confirm these findings. (Registration: subthalamic steering for therapy optimization in Parkinson's Disease ClinicalTrials.gov: NCT03548506, 2018-06-06).

Physical exercise for people with Parkinson's disease: a systematic review and network meta-analysis

BACKGROUND

Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear.

OBJECTIVES

To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs).

SEARCH METHODS

An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. A third author was involved in case of disagreements. We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach.

MAIN RESULTS

We included 154 RCTs with a total of 7837 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 60 (2721 participants), and 48 (3029 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson's Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (60 studies; 2721 participants) suggests that dance and gait/balance/functional training probably have a moderate beneficial effect on the severity of motor signs (dance: mean difference (MD) -10.18, 95% confidence interval (CI) -14.87 to -5.36; gait/balance/functional training: MD -7.50, 95% CI -11.39 to -3.48; moderate confidence), and multi-domain training probably has a small beneficial effect on the severity of motor signs (MD -5.90, 95% CI -9.11 to -2.68; moderate confidence). The evidence also suggests that endurance, aqua-based, strength/resistance, and mind-body training might have a small beneficial effect on the severity of motor signs (endurance training: MD -5.76, 95% CI -9.78 to -1.74; aqua-based training: MD -5.09, 95% CI -10.45 to 0.40; strength/resistance training: MD -4.96, 95% CI -9.51 to -0.40; mind-body training: MD -3.62, 95% CI -7.24 to 0.00; low confidence). The evidence is very uncertain about the effects of "Lee Silverman Voice training BIG" (LSVT BIG) and flexibility training on the severity of motor signs (LSVT BIG: MD -6.70, 95% CI -16.48 to 3.08; flexibility training: MD 4.20, 95% CI -1.61 to 9.92; very low confidence). Quality of life The evidence from the NMA (48 studies; 3029 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -15.15, 95% CI -23.43 to -6.87; moderate confidence). The evidence also suggests that mind-body, gait/balance/functional, and multi-domain training and dance might have a small beneficial effect on QoL (mind-body training: MD -7.22, 95% CI -13.57 to -0.70; gait/balance/functional training: MD -6.17, 95% CI -10.75 to -1.59; multi-domain training: MD -5.29, 95% CI -9.51 to -1.06; dance: MD -3.88, 95% CI -10.92 to 3.00; low confidence). The evidence is very uncertain about the effects of gaming, strength/resistance, endurance, and flexibility training on QoL (gaming: MD -8.99, 95% CI -23.43 to 5.46; strength/resistance training: MD -6.70, 95% CI -12.86 to -0.35; endurance training: MD -6.52, 95% CI -13.74 to 0.88; flexibility training: MD 1.94, 95% CI -10.40 to 14.27; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types.

AUTHORS' CONCLUSIONS

We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.

Bridging the gap between statistical significance and clinical relevance: A systematic review of minimum clinically important difference (MCID) thresholds of scales reported in movement disorders research

Background

Minimum clinically important difference (MCID) is the smallest change in an outcome measure that is considered clinically meaningful. Using validated MCID thresholds for outcomes powers trials adequately to detect meaningful treatment effects, aids in their interpretation and guides development of new outcome measures.

Objectives

To provide a comprehensive summary of MCID thresholds of various symptom severity scales reported in movement disorder.

Methods

We conducted systematic review of the literature and included studies of one or more movement disorders, and reporting MCID scales.

Results

2763 reports were screened. Final review included 32 studies. Risk of bias (RoB) assessment showed most studies were of good quality. Most commonly evaluated scale was Unified Parkinson's Disease Rating Scale (UPDRS) (11 out of 32). Four studies assessing MDS-UPDRS had assessed its different sub-parts, reporting a change of 2.64,3.05,3.25 and 0.9 points to detect clinically meaningful improvement and 2.45,2.51,4.63 and 0.8 points to detect clinically meaningful worsening, for the Part I, II, III and IV, respectively. For Parts II + III, I + II + III and I + II + III + IV, MCID thresholds reported for clinically meaningful improvement were 5.73, 4.9, 6.7 and 7.1 points respectively; while those for clinically meaningful worsening were 4.7, 4.2, 5.2 and 6.3 points, respectively. MCID thresholds reported for other scales included Abnormal Involuntary Movement Scale (AIMS), Toronto Western Spasmodic Torticollis Rating Scale (TWSRS), and Burke-Fahn-Marsden Dystonia Scale (BFMD).

Conclusion

This review summarizes all the MCID thresholds currently reported in Movement disorders research and provides a comprehensive resource for future trials, highlighting the need for standardized and validated MCID scales in movement disorder research.

Which Gait Tasks Produce Reliable Outcome Measures of Freezing of Gait in Parkinson's Disease?

Background

Measurement of freezing of gait (FOG) relies on the sensitivity and reliability of tasks to provoke FOG. It is currently unclear which tasks provide the best outcomes and how medication state plays into this.

Objective

To establish the sensitivity and test-retest reliability of various FOG-provoking tasks for presence and severity of FOG, with (ON) and without (OFF) dopaminergic medication.

Methods

FOG-presence and percentage time frozen (% TF) were derived from video annotations of a home-based FOG-provoking protocol performed in OFF and ON. This included: the four meter walk (4MW), Timed Up and Go (TUG) single (ST) and dual task (DT), 360° turns in ST and DT, a doorway condition, and a personalized condition. Sensitivity was tested at baseline in 63 definite freezers. Test-retest reliability was evaluated over 5 weeks in 26 freezers.

Results

Sensitivity and test-retest reliability were highest for 360° turns and higher in OFF than ON. Test-retest intra-class correlation coefficients of % TF varied between 0.63-0.90 in OFF and 0.18-0.87 in ON, and minimal detectable changes (MDCs) were high. The optimal protocol included TUG ST, 360° turns ST, 360° turns DT and a doorway condition, provoking FOG in all freezers in OFF and 91.9% in ON and this could be done reliably in 95.8% (OFF) and 84.0% (ON) of the sample. Combining OFF and ON further improved outcomes.

Conclusions

The highest sensitivity and reliability was achieved with a multi-trigger protocol performed in OFF + ON. However, the high MDCs for % TF underscore the need for further optimization of FOG measurement.

Physical exercise for people with Parkinson's disease: a systematic review and network meta-analysis

BACKGROUND

Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear.

OBJECTIVES

To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs).

SEARCH METHODS

An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. A third author was involved in case of disagreements.  We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach.

MAIN RESULTS

We included 156 RCTs with a total of 7939 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 71 (3196 participants), and 55 (3283 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (71 studies; 3196 participants) suggests that dance has a moderate beneficial effect on the severity of motor signs (mean difference (MD) -10.32, 95% confidence interval (CI) -15.54 to -4.96; high confidence), and aqua-based, gait/balance/functional, and multi-domain training might have a moderate beneficial effect on the severity of motor signs (aqua-based: MD -7.77, 95% CI -13.27 to -2.28; gait/balance/functional: MD -7.37, 95% CI -11.39 to -3.35; multi-domain: MD -6.97, 95% CI -10.32 to -3.62; low confidence). The evidence also suggests that mind-body training and endurance training might have a small beneficial effect on the severity of motor signs (mind-body: MD -6.57, 95% CI -10.18 to -2.81; endurance: MD -6.43, 95% CI -10.72 to -2.28; low confidence). Flexibility training might have a trivial or no effect on the severity of motor signs (MD 2.01, 95% CI -4.82 to 8.98; low confidence). The evidence is very uncertain about the effects of strength/resistance training and "Lee Silverman Voice training BIG" (LSVT BIG) on the severity of motor signs (strength/resistance: MD -6.97, 95% CI -11.93 to -2.01; LSVT BIG: MD -5.49, 95% CI -14.74 to 3.62; very low confidence). Quality of life The evidence from the NMA (55 studies; 3283 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -14.98, 95% CI -23.26 to -6.52; moderate confidence). The evidence also suggests that endurance training might have a moderate beneficial effect, and that gait/balance/functional and multi-domain training might have a small beneficial effect on QoL (endurance: MD -9.16, 95% CI -15.68 to -2.82; gait/balance/functional: MD -5.64, 95% CI -10.04 to -1.23; multi-domain: MD -5.29, 95% CI -9.34 to -1.06; low confidence). The evidence is very uncertain about the effects of mind-body training, gaming, strength/resistance training, dance, LSVT BIG, and flexibility training on QoL (mind-body: MD -8.81, 95% CI -14.62 to -3.00; gaming: MD -7.05, 95% CI -18.50 to 4.41; strength/resistance: MD -6.34, 95% CI -12.33 to -0.35; dance: MD -4.05, 95% CI -11.28 to 3.00; LSVT BIG: MD 2.29, 95% CI -16.03 to 20.44; flexibility: MD 1.23, 95% CI -11.45 to 13.92; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types.

AUTHORS' CONCLUSIONS

We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.

Exploring a New Cueing Device in People Who Experience Freezing of Gait: Acceptance of a Study Design

Background. Freezing of Gait (FoG) is a disabling symptom of Parkinson’s Disease (PD) and is defined as a “brief episodic absence or marked reduction of forward progression of the feet despite the intention to walk.” Compensatory strategies such as cueing and high frequency vibrotactile stimulation can reduce FoG severity and improve gait parameters. A new Sternal high frequency Vibrotactile Stimulation Device (SVSD) with cueing function has been developed, however the clinical effects of this device are yet to be fully investigated. Objective. The aim of this study was to investigate, if the proposed study design using a SVSD and gait analysis sensor insoles was acceptable for people with PD. Methods. This feasibility study was designed as a randomized cross-over study. Thirteen participants took part in a one off 60-minute data collection session. The acceptability of the study design was assessed with a mixed methods questionnaire considering each step of the study process. Secondary outcome measures were the feasibility of using the 10 Metre Walk Test (10MWT), the Freezing of Gait Score (FoG-Score), and Patient Global Impression of Change (PGI-C) with and without the SVSD. Results. The participants scored all aspects of the study design as very satisfactory. In addition, all participants could perform the secondary outcome measures and were deemed feasible. Feedback from open ended questions provided ideas and considerations for adaptations of future clinical studies. Conclusion. The proposed study design was acceptable for people with PD. Implications. This study design, with small adaptations, can be used for larger studies to evaluate the effect of an SVSD on FoG in people with PD.

Multitarget Transcranial Electrical Stimulation for Freezing of Gait: A Randomized Controlled Trial

BACKGROUND

Treatments of freezing of gait (FOG) in Parkinson's disease are suboptimal.

OBJECTIVE

The aim of this study was to evaluate the effects of multiple sessions of transcranial direct current stimulation (tDCS) targeting the left dorsolateral prefrontal cortex and primary motor cortex (M1) on FOG.

METHODS

Seventy-seven individuals with Parkinson's disease and FOG were enrolled in a double-blinded randomized trial. tDCS and sham interventions comprised 10 sessions over 2 weeks followed by five once-weekly sessions. FOG-provoking test performance (primary outcome), functional outcomes, and self-reported FOG severity were assessed.

RESULTS

Primary analyses demonstrated no advantage for tDCS in the FOG-provoking test. In secondary analyses, tDCS, compared with sham, decreased self-reported FOG severity and increased daily living step counts. Among individuals with mild-to-moderate FOG severity, tDCS improved FOG-provoking test time and self-report of FOG.

CONCLUSIONS

Multisession tDCS targeting the left dorsolateral prefrontal cortex and M1 did not improve laboratory-based FOG-provoking test performance. Improvements observed in participants with mild-to-moderate FOG severity warrant further investigation. © 2021 International Parkinson and Movement Disorder Society.

A feasibility study of dual-task strategy training to improve gait performance in patients with Parkinson's disease

Gait disorders in patients with Parkinson’s disease (PD) impact their mobility and self-dependence. Gait training and dual-task (DT)-training improve gait quality. This study aims to assess the feasibility of a specific, gradually intensified DT-training for PD patients with a special focus on gait performance under single task (ST) and DT conditions. Correlations to Freezing of Gait (FoG) were examined. 17 PD patients (70.1 ± 7.4 years, H&Y Stadium 2–3, FoG-Q 9.0 ± 5.5) participated in a four-week DT-training (1x/week, 60 min) with progressively increasing task difficulty and number of tasks. Gait performance (spatiotemporal parameters) was assessed during ST and DT conditions. The training improved DT gait performance, especially gait velocity + 0.11 m/s; (F_(2,16) = 7.163; p = .0171; η²part = .309) and step length (+ 5.73 cm). Also, physical well-being and absolved walking distance improved significantly. Correlation analyses of the FoG score at baseline with relative change of gait metrics post-training revealed significant correlations with training-induced changes of step length and improvement of gait velocity. Overall, the developed DT-training was feasible and effective. Further studies should examine the long-term benefits and the optimal setting to achieve the highest impact. The study was registered in the DRKS (ID DRKS00018084, 23.1.20).

Measurement Properties of Assessments of Freezing of Gait Severity in People With Parkinson Disease: A COSMIN Review

OBJECTIVE

Parkinson disease (PD) is the second-most common neurodegenerative condition worldwide. Approximately 50% of people with PD experience freezing of gait, a motor symptom associated with falls, disability, and poorer quality of life. Accurate assessment of freezing of gait severity is important for guiding management. The aim of this systematic review was to determine the measurement properties of subjective and objective clinical assessments of freezing of gait severity using the COSMIN methodology to facilitate better outcome measure selection.

METHODS

Three databases (MEDLINE, EMBASE, and CINAHL) were searched. The COSMIN Risk of Bias checklist was used for evaluating quality of included studies. Data on measurement properties were extracted. Where possible, meta-analysis was performed.

RESULTS

Nineteen studies investigating measurement properties of 7 outcome measures (patient-reported outcome measures, n = 3; objective assessment tools, n = 4) were included. Ten studies evaluated the Freezing of Gait Questionnaire. Based on COSMIN criteria, the best performing outcome measures were the Freezing of Gait Questionnaire and the Dynamic Parkinson Gait Scale. Both outcome measures demonstrated sufficient structural validity, internal consistency, reliability, construct validity, and responsiveness. The Freezing of Gait Questionnaire was supported with mostly moderate to high quality of evidence, but the evidence for the Dynamic Parkinson Gait Scale was of low quality due to inadequate sample size.

CONCLUSIONS

Content validity and measurement invariance remain unknown for all outcome measures. The Freezing of Gait Questionnaire is the best measure currently available. Further external validation and reliability studies would strengthen the evidence to support the use of the Dynamic Parkinson Gait Scale.

IMPACT

Awareness of limitations of outcome measures facilitates better selection. Without evidence for content validity and measurement invariance, clinicians should consider if their chosen test accurately measures freezing of gait severity and whether it can be applied in populations different to the original study's population.

LAY SUMMARY

Accurately assessing freezing of gait severity is important for guiding management of this disabling symptom. The best clinical assessment currently available is one that relies on the self-report of patients.