How tandem gait stumbled into the neurological exam: a review

Essential and dystonic head tremor: More similarities than differences

INTRODUCTION

Head tremor is a common symptom of essential tremor (ET) and cervical dystonia (CD). In clinical practice, it is often difficult to distinguish between these two conditions, especially in cases where head tremor predominates.

OBJECTIVES

To investigate which clinical and instrumental methods best differentiate ET and CD in patients with head tremor.

METHODS

65 patients were included, of which 23 were diagnosed with ET and head tremor (HT+), 21 with ET without head tremor (HT-) and 21 with CD and dystonic head tremor. 22 healthy volunteers served as controls. All patients were examined using the rating scales for ET (TETRAS), cervical dystonia (TWSTRS), and ataxia (SARA). The Somatosensory Temporal Discrimination Threshold (STDT) was defined as the shortest interval in which an individual recognizes two tactile stimuli as temporally separated.

RESULTS

TETRAS and SARA scores were higher in the HT+ group compared with HT- and CD, with no significant difference between mild head tremor subscores in HT+ and CD. In most HT+ and CD patients, head tremor disappeared supine. The STDT values were significantly higher in the HT+ group compared with controls.

CONCLUSION

While TWSTRS contributed to assess dystonia severity, the scales of tremor and ataxia were not helpful in differentiating head tremor syndromes. The cessation of head tremor in the supine position could be related to the overall mild head tremor scores in both groups. Increased SARA scores and STDT values in HT+ patients suggest a possible role of cerebellar involvement and altered somatosensory timing that merit further verification.

The instrumented single leg stance test detects early balance impairment in people with multiple sclerosis

Balance impairment is frequent in people with multiple sclerosis (pwMS) and affects risk of falls and quality of life. By using inertial measurement units (IMUs) on the Single Leg Stance Test (SLS) we aimed to discriminate healthy controls (HC) from pwMS and detect differences in balance endurance and quality. Thirdly, we wanted to test the correlation between instrumented SLS parameters and self-reported measures of gait and balance. Fifty-five pwMS with mild (EDSS<4) and moderate disability (EDSS≥4) and 20 HC performed the SLS with 3 IMUs placed on the feet and sacrum and filled the Twelve Item Multiple Sclerosis Walking Scale (MSWS-12) questionnaire. A linear mixed model was used to compare differences in the automated balance measures. Balance duration was significantly longer in HC compared to pwMS (p < 0.001) and between the two disability groups (p < 0.001). Instrumented measures identified that trunk stability (normalized mediolateral and antero-posterior center of mass stability) had the strongest association with disability (R2 marginal 0.30, p < 0.001) and correlated well with MSWS-12 (R = 0.650, p < 0.001). PwMS tended to overestimate own balance compared to measured balance duration. The use of both self-reported and objective assessments from IMUs can secure the follow-up of balance in pwMS.

Prevalence and risk factors for abnormal tandem gait in patients with essential tremor syndrome: A cross-sectional study in Southwest China

Objectives

Patients with essential tremor (ET) syndrome have more prevalent and more serious gait and balance impairments than healthy controls. In this cross-sectional study, we explored whether balance impairments are associated with falls as well as more pronounced non-motor symptoms in patients with ET syndrome.

Methods

We assessed the tandem gait (TG) test, as well as falls or near-falls that occurred over the previous year. Non-motor symptoms-including cognitive deficits, psychological and sleep disorders-were evaluated. In univariate analyses, statistical significance was corrected for multiple comparisons using the Benjamini-Hochberg method. Multiple logistic regression was utilized to evaluate the risk factors of poor TG performance in patients with ET syndrome.

Results

A total of 358 patients with ET syndrome were divided into the abnormal TG (a-TG) and normal TG (n-TG) groups based on their performances in the TG test. We revealed that 47.2% of patients with ET syndrome had a-TG. The patients with a-TG were older, were more likely female, and were more likely present with cranial tremors and falls or near-falls (all adjusted P < 0.01). The patients with a-TG had significantly lower Mini-Mental Status Examination scores, as well as significantly higher Hamilton Depression/Anxiety Rating Scale and Pittsburgh Sleep Quality Index scores. Multiple logistic regression analysis demonstrated that female sex (OR 1.913, 95% CI: 1.180-3.103), age (OR 1.050, 95% CI: 1.032-1.068), cranial tremor scores (OR 1.299, 95% CI: 1.095-1.542), a history of falls or near-falls (OR 2.952, 95% CI: 1.558-5.594), and the presence of depressive symptoms (OR 1.679, 95% CI: 1.034-2.726) were associated with the occurrence of a-TG in patients with ET syndrome.

Conclusion

TG abnormalities may be a predictor of fall risk in patients with ET syndrome and are associated with non-motor symptoms, especially depression.

Balance Impairments in People with Early-Stage Multiple Sclerosis: Boosting the Integration of Instrumented Assessment in Clinical Practice

The balance of people with multiple sclerosis (PwMS) is commonly assessed during neurological examinations through clinical Romberg and tandem gait tests that are often not sensitive enough to unravel subtle deficits in early-stage PwMS. Inertial sensors (IMUs) could overcome this drawback. Nevertheless, IMUs are not yet fully integrated into clinical practice due to issues including the difficulty to understand/interpret the big number of parameters provided and the lack of cut-off values to identify possible abnormalities. In an attempt to overcome these limitations, an instrumented modified Romberg test (ImRomberg: standing on foam with eyes closed while wearing an IMU on the trunk) was administered to 81 early-stage PwMS and 38 healthy subjects (HS). To facilitate clinical interpretation, 21 IMU-based parameters were computed and reduced through principal component analysis into two components, sway complexity and sway intensity, descriptive of independent aspects of balance, presenting a clear clinical meaning and significant correlations with at least one clinical scale. Compared to HS, early-stage PwMS showed a 228% reduction in sway complexity and a 63% increase in sway intensity, indicating, respectively, a less automatic (more conscious) balance control and larger and faster trunk movements during upright posture. Cut-off values were derived to identify the presence of balance abnormalities and if these abnormalities are clinically meaningful. By applying these thresholds and integrating the ImRomberg test with the clinical tandem gait test, balance impairments were identified in 58% of PwMS versus the 17% detected by traditional Romberg and tandem gait tests. The higher sensitivity of the proposed approach would allow for the direct identification of early-stage PwMS who could benefit from preventive rehabilitation interventions aimed at slowing MS-related functional decline during neurological examinations and with minimal modifications to the tests commonly performed.

Motor features associated with cognition in non-demented individuals with essential tremor

INTRODUCTION

Essential tremor (ET) is a clinically heterogeneous disease characterized by motor and non-motor features, including cognitive impairment. In a cross-sectional analysis, we determined whether the presence and severity of motor features of ET are associated with cognitive performance.

METHODS

Participants enrolled in a study that used motor and neuropsychological measures to characterize a cohort of ET subjects. Action tremor severity and additional motor features (rest tremor, intention tremor, cranial tremor, dystonia, tandem gait missteps) were assessed in non-demented participants. Participants completed a cognitive test protocol assessing domains of memory, executive function, attention, visuospatial ability, and language. An average z-score was calculated to represent global cognition.

RESULTS

There were 204 ET participants (mean age 78.6, range 55-95). Participants with 10 missteps were more likely to have MCI than those with 0 or 1 misstep (p < 0.001). In unadjusted linear regression models, action tremor severity (p = 0.010), rest tremor (p < 0.001), and tandem gait missteps (p < 0.001) were negatively associated with global cognition. In adjusted models, only tandem gait missteps were negatively associated with global cognition (p < 0.001). Missteps were also negatively associated with memory (p < 0.001), executive function (p < 0.001), attention (p = 0.011), and visuospatial function (p = 0.043). No other motor features were associated with global cognition in adjusted models (p > 0.05).

CONCLUSION

Among non-demented participants with ET, there is an association between cognitive performance and tandem gait missteps, but no other motor features of ET. This is a first step in establishing impaired tandem gait as a possible indicator of cognitive impairment in patients with ET.

A Dynamic Nomogram to Predict the Risk of Stroke in Emergency Department Patients With Acute Dizziness

Objective

To develop a risk prediction tool for acute ischemic stroke (AIS) for patients presenting to the emergency department (ED) with acute dizziness/vertigo or imbalance.

Method

A prospective, multicenter cohort study was designed, and adult patients presenting with dizziness/vertigo or imbalance within 14 days were consecutively enrolled from the EDs of 4 tertiary hospitals between August 10, 2020, and June 10, 2021. Stroke was diagnosed by CT or MRI performed within 14 days of symptom onset. Participants were followed-up for 30 days. The least absolute shrinkage and selection operator (LASSO) logistic regression analysis was conducted to extract predictive factors that best identified patients at high risk of stroke to establish a prediction model. Model discrimination and calibration were assessed and its prediction performance was compared with the age, blood pressure, clinical features, duration, and diabetes (ABCD2) score, nystagmus scheme, and finger to nose test.

Results

In this study, 790 out of 2,360 patients were enrolled {median age, 60.0 years [interquartile range (IQR), 51–68 years]; 354 (44.8%) men}, with complete follow-up data available. AIS was identified in 80 patients. An online web service tool (https://neuroby.shinyapps.io/dynnomapp/) was developed for stroke risk prediction, including the variables of sex, trigger, isolated symptom, nausea, history of brief dizziness, high blood pressure, finger to nose test, and tandem gait test. The model exhibited excellent discrimination with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.889 (95% CI: 0.855–0.923), compared with the ABCD2 score, nystagmus scheme, and finger to nose test [0.712 (95% CI, 0.652–0.771), 0.602 (95% CI, 0.556–0.648), and 61.7 (95% CI, 0.568–0.666) respectively].

Conclusion

Our new prediction model exhibited good performance and could be useful for stroke identification in patients presenting with dizziness, vertigo, or imbalance. Further externally validation study is needed to increase the strength of our findings.

Bayesian Interpretation of Essential Tremor Plus

Essential tremor (ET) plus is a new tremor classification that was introduced in 2018 by a task force of the International Parkinson and Movement Disorder Society. Patients with ET plus meet the criteria for ET but have one or more additional systemic or neurologic signs of uncertain significance or relevance to tremor (“soft signs”). Soft signs are not sufficient to diagnose another tremor syndrome or movement disorder, and soft signs in ET plus are known to have poor interrater reliability and low diagnostic sensitivity and specificity. Therefore, the clinical significance of ET plus must be interpreted probabilistically when judging whether a patient is more likely to have ET or a combined tremor syndrome, such as dystonic tremor. Such a probabilistic interpretation is possible with Bayesian analysis. This review presents a Bayesian analysis of ET plus in patients suspected of having ET versus a dystonic tremor syndrome, which is the most common differential diagnosis in patients referred for ET. Bayesian analysis of soft signs provides an estimate of the probability that a patient with possible ET is more likely to have an alternative diagnosis. ET plus is a distinct tremor classification and should not be viewed as a subtype of ET. ET plus covers a more-comprehensive phenotyping of people with possible ET, and the clinical interpretation of ET plus is enhanced with Bayesian analysis of associated soft signs.

The Relationship between the Static and Dynamic Balance of the Body, the Influence of Eyesight and Muscle Tension in the Cervical Spine in CAA Patients-A Pilot Study

Cerebral amyloid angiopathy (CAA) is one form of disease of the small vessels of the brain and can cause frequent cerebral hemorrhages as well as other types of stroke. The aim of the study was to analyze the static and dynamic balance of the body and changes in the tension of selected muscles of the cervical spine in patients with CAA after stroke, depending on visual control or its absence, compared to healthy volunteers. Eight stroke patients and eight healthy subjects were examined. The functional Unterberger test and the Biodex SD platform were used to test the dynamic equilibrium, on which the static equilibrium was also assessed. Muscle tension was tested with the Luna EMG device. In static tests, the LC muscle (longus colli) was significantly more active with and without visual control (p = 0.016; p = 0.002), and in dynamic tests, significantly higher results for MOS (p = 0.046) were noted. The comparison of the groups led to the conclusion that the more functional deficits, the more difficult it is to keep balance, also with eye control.

Single-Task and Dual-Task Tandem Gait Performance Across Clinical Concussion Milestones in Collegiate Student-Athletes

OBJECTIVE

To determine the length of time after concussion that impaired tandem gait performance is observed.

DESIGN

Clinical measurement, prospective longitudinal.

SETTING

NCAA collegiate athletic facility.

PARTICIPANTS

Eighty-eight concussed NCAA Division I student-athletes and 30 healthy controls.

INDEPENDENT VARIABLES

Group (concussion/control) and time (Baseline, Acute, Asymptomatic, and RTP).

MAIN OUTCOME MEASURES

Participants completed 4 single-task and dual-task tandem gait trials. The concussion group completed tests at the following time points: preseason (Baseline), within 48 hours after concussion (Acute), on the day symptoms were no longer reported (Asymptomatic), and when cleared to return to sports (RTP). Controls completed the same protocol at similar intervals. The dual-task trials involved minimental style cognitive questions answered simultaneously during tandem gait. We analyzed the best time of the 4 trials, comparing groups with a linear mixed model.

RESULTS

Acutely after concussion, the concussion group performed single-task tandem gait slower (worse) than controls (concussion: 11.36 ± 2.43 seconds, controls: 9.07 ± 1.78 seconds, P < 0.001). The concussion group remained significantly slower than controls (9.95 ± 2.21 vs 8.89 ± 1.65 seconds, P = 0.03) at Asymptomatic day but not RTP. There were significant group (P < 0.001) and time (P < 0.001) effects for dual-task tandem gait. The groups were not significantly different at baseline for single-task (P = 0.95) or dual-task (P = 0.22) tandem gait.

CONCLUSIONS

Our results indicate that tandem gait performance is significantly impaired acutely after concussion, compared with both preseason measures and controls. Postural control impairments were not present when the student-athletes were cleared for RTP. This information can assist clinicians when assessing postural control and determining recovery after a concussive injury.

Diagnostic usefulness of 10-step tandem gait test for the patient with degenerative cervical myelopathy

Tandem gait is considered one of the most useful screening tools for gait impairment. The aim of this study is to evaluate diagnostic usefulness of 10-step tandem gait test for the patients with degenerative cervical myelopathy (DCM). Sixty-two DCM patients were compared to 55 persons without gait abnormalities as control. We counted the number of consecutive steps and graded into five according the number of steps and stability. Five grades of tandem gait were investigated for association with clinical parameters including qualitative Japanese orthopedic association (JOA) sub-score for lower extremities and Nurick scale and quantitative balance and gait assessments. The number of tandem steps were reduced and the grades of tandem gait were differently distributed in the DCM patients compared to controls (steps, 7.1 ± 3.6 versus 9.9 ± 0.4, p < 0.001; grades of 0/1/2/3/4/5, 1/13/14/15/19 versus 0/0/2/15/38, p < 0.001 in patients with DCM and control respectively). Patients with DCM showed more unstable balance and abnormal gait features including slower velocity, shorter strides, wider bases with increased stance phase of a gait cycle compared to the control group. The grades of tandem gait were correlated with JOA sub-score (r = 0.553, p < 0.001) and the Nurick scale (r = - 0.652, p < 0.001) as well as both balance and gait parameters. In DCM patients, tandem gait was impaired and correlated with severity of gait abnormality. The authors believe that 10-step tandem gait test is an objective and useful screening test for evaluating gait disturbance in patients with DCM.

Exploring Interrater Disagreement on Essential Tremor Using a Standardized Tremor Elements Assessment

Background

Patients with upper limb action tremor frequently exhibit additional neurological signs of uncertain significance. Clinicians vary in their interpretation, and interrater agreement on the final diagnosis is poor.

Objectives

A new clinical tool for assessing the presence or absence of clinical signs that are important in axis‐1 classification of tremor patients is introduced: the Standardized Tremor Elements Assessment (STEA). Interrater agreement is determined, and signs leading to disagreement in the final diagnosis are identified.

Methods

Three tremor‐focussed and one dystonia‐focussed movement disorder specialists rated 59 videos of patients with upper limb action tremor syndromes using STEA. Interrater agreements for final diagnosis and STEA items were calculated.

Results

Interrater agreement regarding the final diagnosis was higher within the group of tremor specialists and poor between dystonia and tremor specialists. Greater agreement was found for items characterizing tremor than for signs of dystonia.

Conclusions

Clinical signs leading to diagnostic disagreement were identified with STEA, and STEA should therefore be useful in future studies of diagnostic disagreement. The thresholds for considering neurological signs as soft versus significant for ataxia, parkinsonism, dystonia, etc. are critically important in tremor classification and must be studied across movement disorder subspecialties, not simply within a pool of tremor specialists.

Do We Belittle Essential Tremor by Calling It a Syndrome Rather Than a Disease? No

A task force of the International Parkinson and Movement Disorder Society (MDS) recently published a tremor classification scheme that is based on the nosologic principle of two primary axes for classifying an illness: clinical manifestations (Axis 1) and etiology (Axis 2). An Axis 1 clinical syndrome is a recurring group of clinical symptoms, signs (physical findings), and possibly laboratory results that suggests the presence of at least one underlying Axis 2 etiology. Syndromes must be defined and used consistently to be of value in finding specific etiologies and effective treatments. The MDS task force concluded that essential tremor is a common neurological syndrome that has never been defined consistently by clinicians and researchers. The MDS task force defined essential tremor as a syndrome of bilateral upper limb action tremor of at least 3 years duration, with or without tremor in other locations (e.g., head, voice, or lower limbs), in the absence of other neurological signs (e.g., dystonia, parkinsonism, myoclonus, ataxia, peripheral neuropathy, and cognitive impairment). Deviations from this definition should not be labeled as essential tremor. Patients with additional questionably-abnormal signs or with signs of uncertain relevance to tremor are classified as essential tremor plus. The MDS classification scheme encourages a thorough unbiased phenotyping of patients with tremor, with no assumptions of etiology, pathology, pathophysiology, or relationship to other neurological disorders. The etiologies, pathology, and clinical course of essential tremor are too heterogeneous for this syndrome to be viewed as a disease or a family of diseases.

Longitudinal prediction of falls and near falls frequencies in Parkinson's disease: a prospective cohort study

Introduction and objective

Several prediction models for falls/near falls in Parkinson’s disease (PD) have been proposed. However, longitudinal predictors of frequency of falls/near falls are poorly investigated. Therefore, we aimed to identify short- and long-term predictors of the number of falls/near falls in PD.

Methods

A prospective cohort of 58 persons with PD was assessed at baseline (mean age and PD duration, 65 and 3.2 years, respectively) and 3.5 years later. Potential predictors were history of falls and near falls, comfortable gait speed, freezing of gate, dyskinesia, retropulsion, tandem gait (TG), pain, and cognition (Mini-Mental State Exam, MMSE). After each assessment, the participants registered a number of falls/near falls during the following 6 months. Multivariate Poisson regression was used to identify short- and long-term predictors of a number of falls/near falls.

Results

Baseline median (q1–q3) motor (UPDRS) and MMSE scores were 10 (6.75–14) and 28.5 (27–29), respectively. History of falls was the only significant short-time predictor [incidence rate ratio (IRR), 15.17] for the number of falls/near falls during 6 months following baseline. Abnormal TG (IRR, 3.77) and lower MMSE scores (IRR, 1.17) were short-term predictors 3.5 years later. Abnormal TG (IRR, 7.79) and lower MMSE scores (IRR, 1.49) at baseline were long-term predictors of the number of falls/near falls 3.5 years later.

Conclusion

Abnormal TG and MMSE scores predict the number of falls/near falls in short and long term, and may be indicative of disease progression. Our observations provide important additions to the evidence base for clinical fall prediction in PD.

Fifteen Years of Wireless Sensors for Balance Assessment in Neurological Disorders

Balance impairment is a major mechanism behind falling along with environmental hazards. Under physiological conditions, ageing leads to a progressive decline in balance control per se. Moreover, various neurological disorders further increase the risk of falls by deteriorating specific nervous system functions contributing to balance. Over the last 15 years, significant advancements in technology have provided wearable solutions for balance evaluation and the management of postural instability in patients with neurological disorders. This narrative review aims to address the topic of balance and wireless sensors in several neurological disorders, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, stroke, and other neurodegenerative and acute clinical syndromes. The review discusses the physiological and pathophysiological bases of balance in neurological disorders as well as the traditional and innovative instruments currently available for balance assessment. The technical and clinical perspectives of wearable technologies, as well as current challenges in the field of teleneurology, are also examined.

Balance Assessment of Children with Sensorineural Hearing Loss

This study aimed to assess the balance function in children with sensorineural hearing loss (SNHL) using different tests to assess vestibulospinal pathway and tests to assess vestibular system and to compare the result obtained with those of children with normal hearing sensitivity. Detailed balance assessment was done for 15 children with severe to profound SNHL and 15 children with normal hearing sensitivity in the age range of 6-10 years. The audiological evaluation included pure-tone audiometry, speech audiometry, immittance evaluation, otoacoustic emission, vestibular evoked myogenic potential (cervical VEMP and ocular VEMP), and tests to assess vestibulospinal pathway and cerebellar function, such as Romberg test, Fukuda stepping test, Tandem gait test, and Finger-to-nose test. cVEMP and oVEMP were absent in 8 ears (27%) of a total of 30 ears with SNHL. Statistical analysis shows no significant difference between latency and amplitude of cVEMP peaks and latency of oVEMP peaks across groups. Significant reduction of oVEMP peaks amplitude was seen in children with SNHL compared to children with normal hearing. Fukuda stepping test showed an abnormal response in 2 children with SNHL (13%) and one child could not perform tandem gait test (7%). Children with SNHL showed an evident abnormality on the balance assessment test results. The abnormal function of the vestibular system and the vestibulospinal pathway can compromise the child's motor development and thus needs investigation early in life.

Objective impairment of tandem gait in Parkinson's disease patients increases with disease severity

INTRODUCTION

Tandem gait abnormalities have been reported to increase with advancing age, play a role in fall-prediction in Parkinson's disease, and distinguish it from atypical parkinsonism. Tandem gait has been scored based on the number of side steps off a straight line in these studies. Objective measurement of spatiotemporal tandem gait parameters in Parkinson's disease has not been previously reported.

METHODS

Subjects (74 Parkinson's disease and 28 controls) were enrolled after IRB approval. Those with more than 1 fall/day or a Montreal Cognitive Assessment score <10 were excluded. Subjects tandem walked ("heel to toe") on a 20 foot pressure-sensor mat. Data was collected and analyzed using PKMAS software (Protokinetics).

RESULTS

Compared to controls, on tandem gait, Parkinson's subjects had increased step width, stride width and path width, with a slower stride velocity and an increased time spent in all phases of the gait cycle. Parkinson's subjects also applied greater pressure with each step and had greater step-to-step variability in tandem gait measures. While Hoehn & Yahr stage 1 subjects were not significantly different from controls, stage 2 and 2.5 + groups were different. Parkinson's subjects with freezing of gait also walked with a wider base compared to those without gait freezing. Tandem gait spatiotemporal parameters were not correlated with fall frequency.

CONCLUSIONS

Tandem gait is impaired in Parkinson's disease in a stage-dependent manner, with wider base and increased step-to-step variability, which could suggest involvement of cerebellar and mediolateral balance pathways.

Tandem gait abnormality in Parkinson disease: Prevalence and implication as a predictor of fall risk

INTRODUCTION

We report the prevalence of abnormal tandem gait (TG) in patients with idiopathic Parkinson disease (PD) and its association with symptoms of subjective unsteadiness, falls, freezing of gait, and cognitive impairment.

METHODS

We assessed subjective balance impairment, fall history, antero-posterior postural instability, and TG in PD patients (Hoehn and Yahr (HY) stage 0-4). We recorded the age, sex, current medications, HY stage, Schwab and England (S&E) scale score, and MOCA score for each patient. Logistic regression was used to evaluate age-adjusted associations between TG and other demographic and clinical factors.

RESULTS

A total of 102 patients with PD were assessed. Of those, 63.5% of HY 2 patients and 100% of HY 2.5 and 3 patients had a TG abnormality. The presence of TG abnormality was associated with subjective imbalance, falls, freezing of gait, S&E < 80, and MOCA score <24 after adjustment for age.

CONCLUSIONS

TG abnormality is common in PD, precedes the development of antero-posterior postural instability, is associated with cognitive impairment, and may predict fall risk. A longitudinal study will help determine if TG is a predictor of impending progression from HY 2 to HY 3.

Using Inertial Sensors to Quantify Postural Sway and Gait Performance during the Tandem Walking Test

Vestibular dysfunction typically manifests as postural instability and gait irregularities, in part due to inaccuracies in processing spatial afference. In this study, we have instrumented the tandem walking test with multiple inertial sensors to easily and precisely investigate novel variables that can distinguish abnormal postural and gait control in patients with unilateral vestibular hypofunction. Ten healthy adults and five patients with unilateral vestibular hypofunction were assessed with the tandem walking test during eyes open and eyes closed conditions. Each subject donned five inertial sensors on the upper body (head, trunk, and pelvis) and lower body (each lateral malleolus). Our results indicate that measuring the degree of balance and gait regularity using five body-worn inertial sensors during the tandem walking test provides a novel quantification of movement that identifies abnormalities in patients with vestibular impairment.

Clinical differences in patients with Parkinson's disease according to tandem gait performance

Some of patients with Parkinson's disease (PD) have abnormal tandem gait (TG) performance without any symptoms and signs of cerebellar dysfunction. Clinical difference between patients with good and poor TG performance has not yet been studied. We report the relationship between tandem gait performance and clinical characteristics including 37 patients with PD who had no evidence of cerebellar dysfunction. Using tandem gait test, the patients were divided into two groups (good-TG and poor-TG). We evaluated the two groups with Montreal Cognitive Assessment (MoCA), Mini Mental Status Examination (MMSE), Frontal Assessment Batter (FAB), Beck Depression Index (BDI-II), REM Sleep Behavior Disorder Single-Question Screen (RBD1Q), MDS-UPDRS items related to axial disability and freezing. Fifteen participants were classified as good-TG group and 22 were as poor-TG group. Participants in good-TG group had higher MoCA score and lower BDI-II score. The proportion of participants who answered "yes" to RBD1Q was lower in good-TG group (27%, 4 of 15) than that in poor-TG group (55%, 12 of 22). All participants in good-TG group marked "0" for the MDS-UPDRS item 2.13 which addresses freezing event over the past week, whereas 18% (4 of 22) of participants in poor-TG group marked "1". In conclusion, tandem gait performance may be related to various clinical characteristics including cognitive function, mood, RBD, and freezing in patients with PD.

Exposure to an extreme environment comes at a sensorimotor cost

Long duration space flight is known to induce severe modifications in the sensorimotor and musculoskeletal systems. While in-flight strategies including physical fitness have been used to prevent the loss of bone and muscle mass using appropriate rehabilitative countermeasures, less attention has been put forth in the design of technologies that can quickly and effectively assess sensorimotor function during missions in space. The aims of the present study were therefore (1) to develop a Portable Sensorimotor Assessment Platform (PSAP) to enable a crewmember to independently and quickly assess his/her sensorimotor function during the NASA's Extreme Environment Mission Operations (NEEMO) and (2) to investigate changes in performance of static posture, tandem gait, and lower limb ataxia due to exposure in an extreme environment. Our data reveal that measuring the degree of upper body balance and gait regularity during tandem walking using PSAP provided a sensitive and objective quantification of body movement abnormalities due to changes in sensorimotor performance over the duration of mission exposure.