Project description:Background:This is a case of re-emergent kinetic tremor in Parkinson's Disease (PD). Phenomenology shown:The video shows re-emergent kinetic tremor while drawing a spiral and with repeated attempts to drink water from a cup. Educational value:The kinetic tremor described by patients with PD can be a re-emergent tremor which occurs after a few repetitive movements.
Project description:Although rest tremor is the typical form of tremor associated with Parkinson's disease (PD), particularly the tremor-dominant subtype,1 parkinsonian patients may also exhibit postural tremor. In many parkinsonian patients, this postural tremor emerges after a latency of a few seconds or even minutes. In our original description, we coined the term "re-emergent tremor" to differentiate this postural tremor from essential tremor, which occurs without any latency, and to link it to PD rest tremor that is "reset" after some latency when a new holding posture is assumed.2 The relationship of this re-emergent tremor to the typical rest tremor is supported by the observation that this tremor shares many characteristics with the typical rest tremor, such as the same, 3 to 5-Hz frequency, occasional supinating-pronating component, and relatively good response to dopaminergic therapy. Rarely, postural tremor, occurring after a brief (2-4 seconds) latency can be seen even without observable rest tremor.3 In most patients with PD, it is the postural (re-emergent) tremor that is more troublesome for them than the typical rest tremor, because this re-emergent tremor interferes with their ability to hold objects, such as newspapers, against gravity and results in spilling of liquids. Postural tremor of PD is often misdiagnosed as essential tremor, and this diagnostic challenge can be further confounded when both conditions coexist.4 When that occurs, the postural tremor is present without latency, although the amplitude may gradually increase as the underlying re-emergent tremor becomes more evident.
Project description:BackgroundDespite the significance of tremor in Parkinson's disease (PD) diagnosis, classification, and patient's quality of life, there is a relative lack of data on prevalence and relationship of different tremor types in PD.MethodsThe presence of rest tremor (RT) and action tremor (AT; defined as combination of both postural and kinetic tremor) was determined and RT severity was defined using the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) at baseline in the Progression Marker Initiative (PPMI, n = 423), the Fox Investigation for New Discovery of Biomarkers (BioFIND, n = 118) and the Parkinson's Disease Biomarkers Program (PDBP, n = 873) cohorts.ResultsAcross baseline data of all three cohorts, RT prevalence (58.2%) was higher than AT prevalence (39.0%). Patients with RT had significantly higher (Chi-square test, p < 0.05) prevalence of AT compared to patients without RT in the PPMI (40.0% versus 30.1%), BioFIND (48.0% versus 40.0%) and PDBP (49.9% versus 21.0%) cohorts. Furthermore, patients with AT had significantly (Student t-test, p < 0.05) higher RT severity that those without AT in PPMI (5.7 ± 5.4 versus 3.9 ± 3.3), BioFIND, 6.4 ± 6.3 versus 3.8 ± 4.4) and PDBP (6.4 ± 6.6 versus 3.7 ± 4.4) cohorts. In the BioFIND cohort, the prevalence of all types of tremor and their combinations significantly decreased from the off-state to on-state.DiscussionThe RT is the most frequent tremor type and present in more than half of the PD patients. However, AT is also present in nearly one-third of the PD patients. Our results also indicate that RT and AT may have cross-interactions in PD, and that dopaminergic treatment influences both RT and AT.
Project description:BackgroundResting tremor is one of the most common symptoms of Parkinson's disease. Despite its high prevalence, resting tremor may not be as effectively treated with dopaminergic medication as other symptoms, and surgical treatments such as deep brain stimulation, which are effective in reducing tremor, have limited availability. Therefore, there is a clinical need for non-invasive interventions in order to provide tremor relief to a larger number of people with Parkinson's disease. Here, we explore whether peripheral nerve stimulation can modulate resting tremor, and under what circumstances this might lead to tremor suppression.MethodsWe studied 10 people with Parkinson's disease and rest tremor, to whom we delivered brief electrical pulses non-invasively to the median nerve of the most tremulous hand. Stimulation was phase-locked to limb acceleration in the axis with the biggest tremor-related excursion.ResultsWe demonstrated that rest tremor in the hand could change from one pattern of oscillation to another in space. Median nerve stimulation was able to significantly reduce (- 36%) and amplify (117%) tremor when delivered at a certain phase. When the peripheral manifestation of tremor spontaneously changed, stimulation timing-dependent change in tremor severity could also alter during phase-locked peripheral nerve stimulation.ConclusionsThese results highlight that phase-locked peripheral nerve stimulation has the potential to reduce tremor. However, there can be multiple independent tremor oscillation patterns even within the same limb. Parameters of peripheral stimulation such as stimulation phase may need to be adjusted continuously in order to sustain systematic suppression of tremor amplitude.
Project description:Emergent tremor in Parkinson's disease (PD) can occur during sustained postures or movements that are different from action tremor. Tremor can contaminate the clinical rating of bradykinesia during finger tapping. Currently, there is no reliable way of isolating emergent tremor and measuring the cardinal motor symptoms based on voluntary movements only. In this study, we investigated whether emergent tremor during repetitive alternating finger tapping (RAFT) on a quantitative digitography (QDG) device could be reliably identified and distinguished from voluntary tapping. Ninety-six individuals with PD and forty-two healthy controls performed a thirty-second QDG-RAFT task and the Movement Disorders Society - Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III). Visual identification of tremor during QDG-RAFT was labeled by an experienced movement disorders specialist. Two methods of identifying tremor were investigated: 1) physiologically informed temporal thresholds 2) XGBoost model using temporal and amplitude features of tapping. The XGBoost model showed high accuracy for identifying tremor (area under the precision-recall curve of 0.981) and outperformed temporal-based thresholds. Percent time duration of classifier-identified tremor showed significant correlations with MDS-UPDRS III tremor subscores (r = 0.50, p < 0.0001). There was a significant change in QDG metrics for bradykinesia, rigidity, and arrhythmicity after tremor strikes were excluded (p < 0.01). The results demonstrate that emergent tremor during QDG-RAFT has a unique digital signature and the duration of tremor correlated with the MDS-UPDRS III tremor items. When involuntary tremor strikes were excluded, the QDG metrics of bradykinesia and rigidity were significantly worse, demonstrating the importance of distinguishing tremor from voluntary movement when rating bradykinesia.
Project description:AimsThe purpose of this study was to clarify the dentato-rubro-thalamic (DRT) pathway in action tremor in comparison to normal controls (NC) and disease controls (i.e., rest tremor) by using multi-modality magnetic resonance imaging (MRI).MethodsThis study included 40 essential tremor (ET) patients, 57 Parkinson's disease (PD) patients (29 with rest tremor, 28 without rest tremor), and 41 NC. We used multi-modality MRI to comprehensively assess major nuclei and fiber tracts of the DRT pathway, which included decussating DRT tract (d-DRTT) and non-decussating DRT tract (nd-DRTT), and compared the differences in DRT pathway components between action and rest tremor.ResultsBilateral dentate nucleus (DN) in the ET group had excessive iron deposition compared with the NC group. Compared with the NC group, significantly decreased mean diffusivity and radial diffusivity were observed in the left nd-DRTT in the ET group, which were negatively correlated with tremor severity. No significant difference in each component of the DRT pathway was observed between the PD subgroup or the PD and NC.ConclusionAberrant changes in the DRT pathway may be specific to action tremor and were indicating that action tremor may be related to pathological overactivation of the DRT pathway.
Project description:IntroductionRelease of pigments in the anterior chamber is frequently observed in pigment dispersion syndrome, an autosomal dominant disorder marked by bilateral pigment deposition on the anterior and possibly posterior lens capsule, zonules of the lens, trabecular meshwork, and corneal endothelium, in addition to radial, spoke-like transillumination defects in the mid peripheral iris [J Ayub Med Coll Abbottabad. 2017;29(3):412-414 and Optom Vis Sci. 1995;72(10):756-762]. Pigmentation of the anterior lens surface has also been associated with intraocular inflammation, pseudoexfoliation syndrome, siderosis, antipsychotic medication usage, and remnants of the tunica vasculosa lentis [Br J Ophthalmol. 1998;82(11):1344].Case presentationA 23-year-old female presented to our eye clinic with chief complaint of mild blurring of vision in the right eye and inquired about refractive surgery. The patient denied any previous history of ocular inflammation, trauma, surgery, or use of topical or systemic medications. Slit-lamp examination of the right eye anterior segment was within normal limits except for the crystalline lens anterior capsular which showed confluent pigment deposits stellate in shape over the pupillary axis, whereas left eye examination was completely within normal limits. Ophthalmic examination of the posterior segment was normal in both eyes. Based on her previous ophthalmic history and slit-lamp examination of the right eye, a diagnosis of unilateral congenital lenticular pigmentation was made.ConclusionCongenital lenticular pigmentation is a rare benign entity carrying no surgical indications with a relatively good visual response to optical correction. Recognition of this rare benign condition would add to the ophthalmologist's differential of ocular pigmentation and avoid unnecessary concern and follow-up in more potentially progressive disorders such as pigmentary glaucoma.