Clinical Correlates of Action Tremor in Parkinson Disease

Louis, Elan D.; Levy, Gilberto; Côté, Lucien J.; Mejía, H.; Fahn, Stanley; Marder, Karen

doi:10.1001/archneur.58.10.1630

Cited by 116 publications

(91 citation statements)

References 19 publications

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“…In regards to PD, we found that tremor phenotype can be clustered into 3 subgroups. Although we anticipated differences regarding demographic and/or clinical differences among these subgroups, these variables proved to be consistently similar across the whole sample, as suggested by the study of Louis et al 11 . We also found that tremors that can be electrophysiologically detected with more intensity at rest (subgroup 1) may not be the prototypical tremor in PD.…”

Section: Discussionmentioning

confidence: 54%

Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

Cichaczewski

Munhoz²,

Maia

et al. 2014

Arq. Neuro-Psiquiatr.

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Tremor in essential tremor (ET) and Parkinson's disease (PD) usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. Objective: To present the electrophysiologic findings in PD and ET. Method: Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Results: Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2%) also showed rest tremor. Conclusion: The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD.

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Section: Discussionmentioning

confidence: 54%

Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

Cichaczewski

Munhoz²,

Maia

et al. 2014

Arq. Neuro-Psiquiatr.

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“…Second, as shown in Table 1, there was a significant difference in action tremor scores between the two patient groups. Because resting tremor and action tremor are usually highly interrelated in clinical conditions (Louis et al., 2001; Rana et al., 2014), our results are influenced by this confounding factor. Third, since the CRB‐THA‐MC loop is also involved in other tremor‐related disorders such as essential tremor, which is with overlapping manifestations with parkinsonian resting tremor at initial stages (Cagnan et al., 2014; Nicoletti et al., 2015), the specificity of thalamus for resting tremor still needs further investigation.…”

Section: Discussionmentioning

confidence: 99%

Increased thalamic centrality and putamen–thalamic connectivity in patients with parkinsonian resting tremor

Cao

Xuan

et al. 2016

Brain and Behavior

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IntroductionEvidence has indicated a strong association between hyperactivity in the cerebello‐thalamo‐motor cortical loop and resting tremor in Parkinson's disease (PD). Within this loop, the thalamus serves as a central hub based on its structural centrality in the generation of resting tremor. To study whether this thalamic abnormality leads to an alteration at the whole‐brain level, our study investigated the role of the thalamus in patients with parkinsonian resting tremor in a large‐scale brain network context.MethodsForty‐one patients with PD (22 with resting tremor, TP and 19 without resting tremor, NTP) and 45 healthy controls (HC) were included in this resting‐state functional MRI study. Graph theory‐based network analysis was performed to examine the centrality measures of bilateral thalami across the three groups. To further provide evidence to the central role of the thalamus in parkinsonian resting tremor, the seed‐based functional connectivity analysis was then used to quantify the functional interactions between the basal ganglia and the thalamus.ResultsCompared with the HC group, patients with the TP group exhibited increased degree centrality (p < .04), betweenness centrality (p < .01), and participation coefficient (p < .01) in the bilateral thalami. Two of these alterations (degree centrality and participation coefficient) were significantly correlated with tremor severity, especially in the left hemisphere (p < .02). The modular analysis showed that the TP group had more intermodular connections between the thalamus and the regions within the cerebello‐thalamo‐motor cortical loop. Furthermore, the data revealed significantly enhanced functional connectivity between the putamen and the thalamus in the TP group (p = .027 corrected for family‐wise error).ConclusionsThese findings suggest increased thalamic centrality as a potential tremor‐specific imaging measure for PD, and provide evidence for the altered putamen–thalamic interaction in patients with resting tremor.

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“…In the second study [5] instead, only PD patients who were on their usual therapeutic regimen were studied, which means any effect of pharmacological treatment on RET was not evaluated. In this regard, unpublished investigations from our group on the presence of RET in PD patients who were evaluated both off and on treatment showed that RET was more frequent when patients were evaluated off treatment.In PD, RET usually involves the upper limbs [1,[4][5][6] and is bilateral in 50% of cases [5]. Recent clinical reports have described patients with PD with RET even in the jaw [7] and tongue [8,9].…”

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confidence: 99%

“…The first, in which the aim was to evaluate occurrence and the clinical features of action tremor [4], showed that RET was present in 32% (63/197) of patients with PD. A second study [5] specifically designed to investigate RET in PD reported that 20% (42/210) of patients have RET.…”

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confidence: 99%

“…A second study [5] specifically designed to investigate RET in PD reported that 20% (42/210) of patients have RET. In the first study, the authors [4] did not, however, specify whether PD patients were evaluated while they were off or on pharmacological treatment. In the second study [5] instead, only PD patients who were on their usual therapeutic regimen were studied, which means any effect of pharmacological treatment on RET was not evaluated.…”

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confidence: 99%

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Re-Emergent Tremor: What do we know so Far?

2017

CANN

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Re-emergent Tremor (RET) is defined as a tremor of the upper limbs that appears after a varying latency during a posture. Although RET was first described almost 20 years ago [1], few studies have investigated the clinical features of RET.In 1999, Jankovic et al., first described RET in a small sample of patients affected by Parkinson's Disease (PD). The authors observed that PD patients with rest tremor may show a postural tremor starting after a variable delay while maintaining the upper limbs outstretched [1]. Given that RET and resting tremor showed similar clinical features,Jankovic et al., hypothesized that RET depends on the activity of the central oscillators responsible for resting tremor that is reset with some latency after the assumption of a new posture. In the same study, Jankovic et al., also observed that patients with essential tremor never showed RET, thus suggesting that RET was specific to PD. This hypothesis was supported by Schwingenschuh et al., [2] who compared upper limb tremor in patients with PD and patients with "Scans Without Evidence of Dopaminergic Deficit" (SWEDD) and reported that only patients with PD had RET. No studies have detected RET in patients with atypical parkinsonisms or dystonic tremor. By contrast, De Laat et al., [3] described a SWEDD patient who had RET.The presence of RET, therefore, seems to be strongly suggestive of PD but RET should be always assessed in patients with tremor syndromes.Only two studies have investigated the occurrence of RET in PD. The first, in which the aim was to evaluate occurrence and the clinical features of action tremor [4], showed that RET was present in 32% (63/197) of patients with PD. A second study [5] specifically designed to investigate RET in PD reported that 20% (42/210) of patients have RET. In the first study, the authors [4] did not, however, specify whether PD patients were evaluated while they were off or on pharmacological treatment. In the second study [5] instead, only PD patients who were on their usual therapeutic regimen were studied, which means any effect of pharmacological treatment on RET was not evaluated. In this regard, unpublished investigations from our group on the presence of RET in PD patients who were evaluated both off and on treatment showed that RET was more frequent when patients were evaluated off treatment.In PD, RET usually involves the upper limbs [1,[4][5][6] and is bilateral in 50% of cases [5]. Recent clinical reports have described patients with PD with RET even in the jaw [7] and tongue [8,9]. No studies have yet reported RET in the lower limbs, though this may be due to the fact that the investigation of postural tremor in the lower limbs is not a common clinical procedure.RET is considered as a clinical variant of resting tremor. The clinical features of patients with RET and patients with isolated resting tremor have been compared in two different studies [5,10]. Both studies showed that the two groups of patients, who were on an equivalent mean levodopa dose, did not differ significantly ...

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Clinical Correlates of Action Tremor in Parkinson Disease

Cited by 116 publications

References 19 publications

Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

Increased thalamic centrality and putamen–thalamic connectivity in patients with parkinsonian resting tremor

Re-Emergent Tremor: What do we know so Far?

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