scholarly journals Diagnosis of orthostatic tremor using smartphone accelerometry

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicholas E. Calvo ◽  
Joseph M. Ferrara
Keyword(s):  
Movement Disorder ◽  
Surface Electromyography ◽  
Primary Outcome ◽  
Fear Of Falling ◽  
Spastic Paraplegia ◽  
Functional Movement ◽  
Orthostatic Tremor ◽  
Neurology Clinic ◽  
Low Amplitude ◽  
Larger Sample

Abstract Background Primary orthostatic tremor (OT) is a rare movement disorder characterized by a 13–18 Hz leg tremor, which arises when standing and is relieved by walking/sitting. Those affected generally do not fall, but experience fear of falling, lessened by ambulation. Because of its low amplitude, the tremor is not readily visible, and diagnosis requires confirmation with surface electromyography (sEMG). Recently, applications using the accelerometer feature of smartphones have been used to detect and quantify tremors, including OT, though the accuracy of smartphone accelerometry (SPA) in diagnosing OT is unknown. Methods We completed SPA in consecutive adults (18+ years), who presented to our neurology clinic with either subjective leg shakiness upon standing or unsteadiness when standing that lessened with ambulation, which comprised 59 of 2578 patients. We assessed tremor using the StudyMyTremor application on an iPhone 6 s adhered with tape to the patient’s tibialis anterior. Surface electromyography was completed on the same muscle. The primary outcome of this study was to determine SPA’s sensitivity and specificity in detecting OT compared with surface electromyography. Results Fifty-nine patients with the following diagnoses were included: OT (6), Parkinson’s disease, Hereditary Spastic Paraplegia, orthostatic hypotension, essential tremor, spinal cerebellar ataxia, sensory ataxia and functional movement disorder. Smartphone accelerometry detected a 13–18 Hz tremor in 5 of 6 patients diagnosed with OT by sEMG with no false positives in other conditions, yielding a sensitivity of 83%, specificity of 100% in the cohort we studied. Conclusions Though a larger sample size is desirable, preliminary data suggest that smartphone accelerometry is an alternative to surface electromyography in diagnosing OT.

scholarly journals Diagnosis of Orthostatic Tremor Using Smartphone Accelerometry Running Head: Smartphone Accelerometry for Orthostatic Tremor

2021 ◽  
Author(s):  
Nicholas E. Calvo ◽  
Joseph M. Ferrara
Keyword(s):  
Movement Disorder ◽  
Surface Electromyography ◽  
Primary Outcome ◽  
Fear Of Falling ◽  
Functional Movement ◽  
Orthostatic Tremor ◽  
Neurology Clinic ◽  
Low Amplitude ◽  
Running Head ◽  
Larger Sample

Abstract Background: Primary orthostatic tremor (OT) is a rare movement disorder characterized by a 13-18 Hz leg tremor, which arises when standing and is relieved by walking/sitting. Those affected generally do not fall, but experience fear of falling, lessened by ambulation. Because of its low amplitude, the tremor is not readily visible, and diagnosis requires confirmation with surface electromyography. Recently, applications using the accelerometer feature of smartphones have been used to detect and quantify tremors, including OT, though the accuracy of smartphone accelerometry in diagnosing OT is unknown. Methods: We completed SPA in consecutive adults (18+ years), who presented to our neurology clinic with either subjective leg shakiness upon standing or unsteadiness when standing that lessened with ambulation. We assessed tremor using the StudyMyTremor application on an iPhone 6s adhered with tape to the patient’s tibialis anterior. Surface electromyography was completed on the same muscle. The primary outcome of this study was to determine SPA’s sensitivity and specificity in detecting OT compared with surface electromyography. Results: Fifty-nine patients with the following diagnoses were included: OT (6), Parkinson’s disease, Hereditary Spastic Paraplegia, orthostatic hypotension, essential tremor, spinal cerebellar ataxia, sensory ataxia and functional movement disorder. Smartphone accelerometry detected a 13-18 Hz tremor in 5 of 6 patients diagnosed with OT by surface electromyography with no false positives in other conditions, yielding a sensitivity of 83%, specificity of 100% in the cohort we studied. Conclusions: Though a larger sample size is desirable, preliminary data suggest that smartphone accelerometry is an alternative to surface electromyography in diagnosing OT.

Functional Movement Disorder in a Family with PRRT2-Associated Paroxysmal Kinesigenic Dyskinesia

2014 ◽  
Vol 45 (S 01) ◽  
Author(s):  
D. Ebrahimi-Fakhari ◽  
K. Kang ◽  
U. Kotzaeridou ◽  
S. Schubert-Bast ◽  
J. Kohlhase ◽  
...  
Keyword(s):  
Movement Disorder ◽  
Functional Movement ◽  
Paroxysmal Kinesigenic Dyskinesia

Abstract P603: Atrial Cardiopathy and Brain Infarction in Multiple Vascular Territories in the ARCADIA Trial

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Hooman Kamel ◽  
Keyword(s):  
Primary Outcome ◽  
Brain Infarction ◽  
Prevalence Ratio ◽  
Posterior Circulation ◽  
P Wave ◽  
Secondary Outcome ◽  
Vascular Territory ◽  
Brain Infarcts ◽  
Left And Right ◽  
Larger Sample

Introduction: Some embolic strokes of undetermined source (ESUS) are likely caused by occult cardiac embolism. One potential cardioembolic source is atrial cardiopathy without atrial fibrillation (AF). Patients with cardiac embolism more often have brain infarcts in multiple vascular territories than those with stroke mechanisms not involving a central embolic source. Hypothesis: In patients with ESUS, atrial cardiopathy is associated with brain infarction in multiple vascular territories. Methods: The ARCADIA trial is enrolling ESUS patients, screening them for atrial cardiopathy, and randomly assigning those with atrial cardiopathy to aspirin or apixaban. In the trial, atrial cardiopathy is defined as ≥1 of the following: P-wave terminal force >5,000 μV*ms in ECG lead V 1 , serum NT-proBNP >250 pg/mL, and left atrial diameter index ≥3 cm/m 2 on echocardiogram. Site investigators report whether the index CT or MRI showed brain infarction in the left carotid, right carotid, or posterior circulation, or some combination. In this analysis, our primary outcome was brain infarction in more than one of these three vascular territories. Our secondary outcome was infarction in both the left and right carotid territories. Results: Among 1,707 ESUS patients enrolled in ARCADIA, 679 (39.8%) met the trial’s randomization criteria for atrial cardiopathy and 213 (12.5%) had multi-territorial brain infarcts. The prevalence of brain infarction in more than one vascular territory was 14.0% in those with atrial cardiopathy versus 11.5% in those without (prevalence ratio, 1.22; 95% CI, 0.95-1.57). The prevalence of brain infarction in both the left and right carotid territories was 9.1% in those with atrial cardiopathy versus 7.4% in those without (prevalence ratio, 1.24; 95% CI, 0.90-1.70). Conclusions: These preliminary analyses from ARCADIA suggest a possible association between atrial cardiopathy and brain infarction in multiple vascular territories, but further analysis of a larger sample is needed to conclusively test whether our atrial cardiopathy definition is associated with the classic neuroimaging profile of cardiac embolism.

scholarly journals Outcome assessment by central adjudicators in randomised stroke trials: Simulation of differential and non-differential misclassification

2020 ◽  
Vol 5 (2) ◽  
pp. 174-183 ◽  
Author(s):  
Peter J Godolphin ◽  
Philip M Bath ◽  
Christopher Partlett ◽  
Eivind Berge ◽  
Martin M Brown ◽  
...  
Keyword(s):  
Sample Size ◽  
Outcome Assessment ◽  
Treatment Effect ◽  
Primary Outcome ◽  
Event Rate ◽  
Considerable Proportion ◽  
Binary Outcome ◽  
Primary Trial ◽  
Differential Misclassification ◽  
Larger Sample

Introduction Adjudication of the primary outcome in randomised trials is thought to control misclassification. We investigated the amount of misclassification needed before adjudication changed the primary trial results. Patients (or materials) and methods: We included data from five randomised stroke trials. Differential misclassification was introduced for each primary outcome until the estimated treatment effect was altered. This was simulated 1000 times. We calculated the between-simulation mean proportion of participants that needed to be differentially misclassified to alter the treatment effect. In addition, we simulated hypothetical trials with a binary outcome and varying sample size (1000–10,000), overall event rate (10%–50%) and treatment effect (0.67–0.90). We introduced non-differential misclassification until the treatment effect was non-significant at 5% level. Results For the five trials, the range of unweighted kappa values were reduced from 0.89–0.97 to 0.65–0.85 before the treatment effect was altered. This corresponded to 2.1%–6% of participants misclassified differentially for trials with a binary outcome. For the hypothetical trials, those with a larger sample size, stronger treatment effect and overall event rate closer to 50% needed a higher proportion of events non-differentially misclassified before the treatment effect became non-significant. Discussion: We found that only a small amount of differential misclassification was required before adjudication altered the primary trial results, whereas a considerable proportion of participants needed to be misclassified non-differentially before adjudication changed trial conclusions. Given that differential misclassification should not occur in trials with sufficient blinding, these results suggest that central adjudication is of most use in studies with unblinded outcome assessment. Conclusion: For trials without adequate blinding, central adjudication is vital to control for differential misclassification. However, for large blinded trials, adjudication is of less importance and may not be necessary.

scholarly journals Levodopa-Responsive Primary Slow Orthostatic Tremor: A Premotor Sign of Parkinson’s Disease?

2020 ◽  
Vol 12 (1) ◽  
pp. 1-6
Author(s):  
Fumihito Yoshii ◽  
Wakoh Takahashi ◽  
Koji Aono
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Surface Electromyography ◽  
Specific Binding ◽  
Low Frequency ◽  
Orthostatic Tremor ◽  
Specific Binding Ratio ◽  
Dopaminergic Medication ◽  
Neurological Signs ◽  
Dat Spect

We present a case of primary orthostatic tremor (OT) responsive to dopaminergic medication. The patient was a 62-year-old woman, who had leg tremor on standing for 2 years. No parkinsonian or other neurological signs were observed. Surface electromyography of the quadriceps muscles showed regular 5–6 Hz muscle discharges. [123I]-FP-CIT DAT-SPECT imaging revealed decreased specific binding ratio values in the striatum compared with age-matched controls. Her leg tremor almost completely disappeared following administration of levodopa 200 mg and pramipexole 0.75 mg. Since her OT with low-frequency discharge was responsive to dopaminergic medication, we speculate that it may be a premotor sign of Parkinson’s disease.

Symptomatic orthostatic tremor in pontine lesions

Neurology ◽  
1997 ◽  
Vol 49 (5) ◽  
pp. 1439-1441 ◽  
Author(s):  
J. Benito-León ◽  
J. Rodríguez ◽  
M. Ortí-Pareja ◽  
L. Ayuso-Peralta ◽  
F. J. Jiménez-Jiménez ◽  
...  
Keyword(s):  
Movement Disorder ◽  
Orthostatic Tremor ◽  
Central Origin ◽  
Radiologic Features

Orthostatic tremor (OT) is a rare movement disorder that consists of involuntary shaking of the legs and trunk present only on standing. Although the origin and the mechanism of this condition are not well understood, the neurophysiologic abnormalities and PET studies suggest a central origin. We describe the clinical and radiologic features of two patients with symptomatic OT and associated pontine lesions, and conclude that OT may arise from dysfunction of the cerebellum or related pontine structures.

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