A longitudinal study of tremor frequencies in Parkinson’s disease and essential tremor

ObjectiveThere is evidence that the tremor frequency in essential tremor (ET) decreases with time. Longitudinal studies on the evolution of tremor frequencies in Parkinson’s disease (PD) have so far not been published. Here, we present a longitudinal analysis of tremor frequencies in PD and ET.MethodsWe analyzed the standardized accelerometric and electromyographic tremor recordings of 53 patients with PD and 38 patients with ET who underwent repeated routine tremor recordings between 1991 and 2002.ResultsIn an average follow-up period of 44.9 months in PD and 50.6 months in ET, the average number of tremor recordings was 3.3 in PD and 3.7 in ET. In both disorders, tremor frequencies tended to decrease with time. The average annual decrease of the tremor frequency was 0.09 Hz/year in Parkinsonian rest tremor, 0.08 Hz/year in Parkinsonian postural tremor and 0.12 Hz/year in ET.ConclusionsThe tremor frequency decreases with time in both PD and ET. The similarity of this decrease in PD and ET may point to a common underlying pathophysiological mechanism.SignificanceDecreasing tremor frequencies with time may be functionally important by inducing larger tremor amplitudes due to the low-pass filtering properties of muscles and limbs.     

Patterns of intrinsic brain activity in essential tremor with resting tremor and tremor-dominant Parkinson’s disease

Brain Imaging and Behavior - The clinical pictures of essential tremor (ET) with resting tremor (rET) and tremor-dominant Parkinson’s disease (tPD) are often quite mimic at the early stage,...     

[11C]d-threo-methylphenidate PET in patients with Parkinson’s disease and essential tremor

Summary. Twenty Parkinson’s disease (PD) patients, 6 patients with essential tremor and 10 healthy controls were studied with the dopamine transporter ligand [¹¹C]d-threo-methylphenidate ([¹¹C]dMP) and positron emission tomography (PET) to assess dopamine terminal loss in relation to disease duration and motor disability. Dopamine transporter availability was expressed as [¹¹C]dMP binding potential (BP_dMP) in percentage of the mean of healthy controls. In PD patients (age at onset 57.7 ± 8.9 yrs; disease duration 5.2 ± 3.3 yrs; UPDRS motor score 24.2 ± 9.8; Hoehn & Yahr 2.1 ± 0.8; mean ± SD) BP_dMP was reduced to 30% (range: 11–55%) in the putamen and 52% (range: 14–96%) in the caudate nucleus. BP_dMP in the putamen closely correlated with the UPDRS motor score (r = −0.79, p < 0.001), and disease duration (r = −0.76, p < 0.001) but not with age at onset. The correlation with the UPDRS score depended on akinesia and rigidity, while the tremor scores were related neither to putamen nor caudate BP_dMP. Interestingly, when plotted over disease duration, PD patients with severe asymmetry of symptoms showed significantly lower BP_dMP in the contralateral putamen (exponential fit: 34% at onset) than the other PD patients (41% at onset), indicating a different symptomatic threshold of these subgroups and an even closer correlation with the hypothetical “true” disease duration. The exponential fit across all patients indicated a mean symptomatic threshold of 37% contra- and 62% ipsilateral, corresponding with an observed mean BP_dMP of 51% (average contra- and ipsilateral) in those patients with disease duration less than one year. No differences in BP_dMP were observed between patients with essential tremor and healthy controls. [¹¹C]dMP appears to be a useful and sensitive marker of dopaminergic dysfunction in PD and can be used to assess and monitor disease severity. Both authors contributed equally     

Family history of hand tremor in patients with early Parkinson’s disease

Some patients with Parkinson’s disease (PD) report hand tremors in their relatives. This study aimed to compare the clinical characteristics of early PD in patients with and without a family history of hand tremor. This study included 337 early and drug-naïve patients with PD. The family history of hand tremor was obtained from the patients and their caregivers. Motor and non-motor symptoms of PD were assessed using the appropriate scales. A family history of hand tremor was present in 27 of 337 patients with PD (8.0%). Patients with a family history of hand tremor had significantly higher scores for rest tremors than those without. No significant differences were found in action tremor, bradykinesia, rigidity, gait, or posture scores between the two groups. The proportion of tremor-dominant subtypes was higher in patients with a family history of hand tremor than in those without (51.8% vs. 28.7%). Patients with PD, with a family history of hand tremor, had significantly lower scores in the urinary and sexual subdomains of the Non-Motor Symptoms Scale for PD than in those without. A family history of hand tremor affects the motor and non-motor symptoms in patients with early PD. It is necessary to investigate the family history of hand tremor in patients with PD.     

Clinical determinants of primary and secondary fatigue in patients with Parkinson’s disease

Clinical and psychosocial factors associated separately with primary and secondary fatigue in Parkinson’s disease (PD) patients have not been thoroughly studied before. The aim of our study was to assess factors associated with different fatigue domains in groups with primary and secondary fatigue in PD separately. We divided 165 non-demented PD patients according to the absence/presence of depression, anxiety and excessive somnolence into groups with primary fatigue (N = 63) and with secondary fatigue (N = 102). Fatigue domains examined using the multidimensional fatigue inventory were associated through multiple linear regression analyses for each group separately with sociodemographic data, disease duration, functional status as assessed by the Unified Parkinson’s Disease Rating Scale, treatment, depression, anxiety, excessive somnolence and sleep quality. Out of the assessed non-motor symptoms, fatigue was the most frequent (77.6 %). The prevalence of fatigue in the secondary fatigue group was significantly higher than in the primary fatigue group. Both fatigue groups differed significantly in factors associated with different fatigue domains. Functional status or other disease-related factors were not associated with primary fatigue. In the secondary fatigue group, we found associations between some fatigue domains and functional status, older age, male gender and higher anxiety scores. To our knowledge, this is the first study to separately describe clinical determinants and psychosocial factors associated with different fatigue domains in primary and secondary fatigue in PD, underlining the importance of distinguishing primary and secondary fatigue in future PD studies and clinical practice.     

Eye movement abnormalities in essential tremor versus tremor dominant Parkinson’s disease

ObjectiveTo show that eye movement abnormalities differ between essential tremor (ET) and tremor dominant Parkinson’s disease (PD-T), and that these abnormalities reflect cerebellar dysfunction in ET and basal ganglia pathology in PD-T.MethodsIn this exploratory study, in 23 patients with ET, 21 age-matched patients with PD-T, and 19 age-matched healthy controls (HCs), we investigated visually guided saccades, antisaccades, and smooth pursuit eye movements (SPEM).ResultsWhile the ET group had a normal gain (saccade amplitude/target amplitude) and latency of saccades, the PD-T group had hypometric visually guided saccades, and a prolonged latency of visually guided saccades and antisaccades. The SPEM gain was similarly low in both ET and PD-T and was significantly lower in both patient groups than in the HC group.ConclusionsIn ET, SPEM gain was reduced in the presence of normal saccades, whereas in PD-T, the reduced SPEM gain was accompanied by delayed saccade initiation and hypometric saccades, in line with cerebellar dysfunction in ET and basal ganglia dysfunction in PD-T.SignificanceThese findings support the presumed cerebellar pathology in ET. In addition, the difference in saccade features may contribute to the groundwork for a quantitative diagnostic test to differentiate between these disorders.     

Re-emergent tremor in Parkinson’s disease: Clinical and accelerometric properties

Re-emergent tremor (RET) and the classical parkinsonian rest tremor were considered as two different phenomena of the same central tremor circuit. However, clinical and accelerometric characteristics of these tremors were not previously compared in a single study. We evaluated disease characteristics and accelerometric measurements of two tremor types in 42 patients with Parkinson’s disease. Disease specific features and accelerometric measurements of peak frequency, amplitude at peak frequency and the root mean square (RMS) amplitude of two tremor types were compared. Eighteen patients had RET and the mean latency of the RET was 9.48 (±9.2) s. Groups of only rest tremor and RET did not differ significantly in age of disease onset, disease duration and severity and mean levodopa equivalent dose. Comparison of peak frequency and amplitude at peak frequency were not different between the groups, but RMS amplitude was significantly higher in the RET group (p = 0.03). RMS amplitude of RET was also correlated with disease severity (r = .48, p = 0.04). These results support the previous notion that rest tremor and RET are analogue, both are triggered by the same central ossilator with RET being only the suppression of the rest tremor due to arm repositioning.     

Retinal nerve changes in patients with tremor dominant and akinetic rigid Parkinson’s disease

Parkinson disease is a multisystem neurodegenerative disease which involves not only basal ganglia and extrapyramidal system but also many other neurologic systems such as retinal ganglion cells. Optical coherence tomography (OCT) is a non-invasive method for assessment of retinal nerve fiber layer (RNFL) thickness and its changes in different diseases. To evaluate the RNFL thickness in patients with Parkinson disease (PD), we performed OCT in patients with PD and compared it with a control group. From October 2010 to July 2011, 27 PD patients (54 eyes) and 25 healthy persons (50 eyes) were entered to this analytical cross-sectional study according to the defined criteria. PD patients were categorized into two groups “akinetic rigid (AR) and tremor dominant (TD)”. RNFL was divided into four quadrants and was assessed by OCT. Afterwards; the data were analyzed by bivariate and multivariate models. The RNFL thickness in PD was significantly lower than the control group. Also, the thicknesses of inferior and nasal quadrants of RNFL in TD group were significantly more than AR group. According to these findings, OCT can be used as a sensitive and objective marker for assessment of early neurodegenerative changes of PD and early initiation of neuroprotective treatments. Future studies with adequate sample sizes are recommended to investigate interactions between age, distribution of the disease and type of PD as well as the effects of individual factors.     

Brain SPECT can differentiate between essential tremor and early-stage tremor-dominant Parkinson’s disease

There are no confirmatory or diagnostic tests or tools to differentiate between essential tremor (ET) and tremor in idiopathic Parkinson’s disease (PD). Although a number of imaging studies have indicated that there are differences between ET and PD, the functional imaging study findings are controversial. Therefore, we analyzed regional cerebral blood flow (CBF) by perfusion brain single-photon emission computed tomography (SPECT) to identify differences between ET and tremor-dominant Parkinson’s disease (TPD). We recruited 33 patients with TPD, 16 patients with ET, and 33 healthy controls. We compared the severity of tremor symptoms by comparing the Fahn-Tolosa-Marin rating scale (FTM) score and the tremor score from Unified Parkinson’s Disease Rating Scale (UPDRS) between TPD and ET patients. Subjects were evaluated by neuropsychological assessments, MRI and perfusion SPECT of the brain. Total FTM score was significantly higher in ET patients than TPD patients. However, there was no significant difference in FTM Part A scores between the two patient groups, while the scores for FTM Part B and C were significantly higher in ET patients than TPD patients. Brain SPECT analysis of the TPD group demonstrated significant hypoperfusion of both the lentiform nucleus and thalamus compared to the ET group. Brain perfusion SPECT may be a useful clinical method to differentiate between TPD and ET even during early-phase PD, because the lentiform nucleus and thalamus show differences in regional perfusion between these two groups during this time period. Additionally, we found evidence of cerebellar dysfunction in both TPT and ET.     

Fluctuating cognition and different cognitive and behavioural profiles in Parkinson’s disease with dementia: comparison of dementia with Lewy bodies and Alzheimer’s disease

To examine the occurrence of fluctuating cognition (FC) in a group of patients with Parkinson’s disease with dementia (PDD), and to determine whether the presence of FC in PDD is associated with a pattern of cognitive and behavioural disturbances similar to the one shown by patients affected by dementia with Lewy bodies (DLB), a cluster analysis was carried out on the scores obtained by 27 PDD patients on the Clinician Assessment of Fluctuation Scale (CAF). The analysis separated the PDD patients into two subgroups, called PDD non-fluctuators (PDDNF; CAF ≤ 2) and PDD fluctuators (PDDF; CAF > 2). The two groups underwent a cognitive and behavioural evaluation. Their scores were compared with those obtained by DLB and Alzheimer’s disease (AD) patients. When exploring the cognitive performance of the patients with the Dementia Rating Scale-2 (DRS-2), PDDF had a similar pattern of impairments compared to DLB, which involved prevalently the attention and initiation/perseveration domains, and which was significantly more pronounced compared to that shown by PDDNF. The main behavioural finding of the study was the similar incidence of visual hallucinations in the PDDF and DLB groups, which was significantly higher compared to PDDNF and AD. Our results confirmed the hypothesis that subgroups with different cognitive profiles exist within PDD and that the occurrence of FC is the clinical variable associated with a DLB pattern of impairment in PDD. In conclusion, our study suggests that when FC occurs in PDD this syndrome becomes clinically undistinguishable from DLB.     

Transcranial sonography on Parkinson’s disease and essential tremor in a Chinese population

We analyzed the results of transcranial sonography (TCS) on 110 Parkinson's disease (PD) patients, 30 essential tremor (ET) patients and 110 controls in a Chinese population and compared our findings to the previous literatures. The echo signal intensity of midbrain substantia nigra (SN) was measured and divided into grade I-V. If the high echo signal intensity (grade III, IV or V) was detected in either side of SN, it was measured as well as the whole area of midbrain and the ratio of both sides of SN hyperechogenicity to the whole area of midbrain (S/M) were calculated. In addition, the width of the third ventricle in the level of thalamus was also determined. There were more individuals with the grade of SN?≥?III in PD group (100/110, 85.45%) than these in ET group (4/30, 13.33%, x ( 2 )?=?58.38, P?相似文献   

The early course of affective and cognitive symptoms in de novo patients with Parkinson’s disease

Neuropsychiatric and cognitive symptoms are common in patients with Parkinson’s disease (PD) from the early stage of the disease but their course is still unclear. In this study we investigated prospectively the progression of affective and cognitive symptoms and disorders in de novo idiopathic PD patients. Twenty-four de novo drug naïve PD patients underwent a comprehensive neurological, psychopathological and neuropsychological evaluation at the first diagnostic visit (OFF), after 4?6 months when the antiparkinsonian therapy regimen was stabilized (ON-1), and at one year following the ON-1 follow-up visit (ON-2). Generalized least squares analysis revealed a significant improvement over time in the depressive mood, short and long term episodic verbal memory, visual memory, and the motor symptoms. Pairwise comparisons showed a significant change from OFF to ON-1 for all the aforementioned variables, except for short term episodic verbal memory which approached significance. A significant improvement from ON-1 to ON-2, however, was shown for short term episodic verbal memory. An ancillary analysis indicated that overall level and change in a number of cognitive variables, but not depression, was conditional upon age of onset, education, and sometime gender. In conclusion, early stage PD is not associated with affective and cognitive deterioration. On the contrary, very specific neuropsychiatric and cognitive symptoms may improve. This study provides Class III evidence that antiparkinsonian treatment commonly used in the clinical practice improves memory performance and depression severity in de novo patients with PD.     

Development of Parkinson’s disease in patients with Narcolepsy

Although amphetamine drugs can damage dopaminergic axons, it is unknown whether chronic treatment with amphetamine increases the risk of developing Parkinson's disease (PD). Of 1,152 consecutive PD patients, 3 had a prior diagnosis of narcolepsy. This rate is five times higher than expected (p = 0.02). These patients had typical onset of narcolepsy and underwent treatment with amphetamine. Although preliminary, this observation raises the possibility that some factors intrinsic to narcolepsy or its treatment may be a risk factor for PD.     

Beyond tremor and rigidity: non-motor features of Parkinson’s disease

Parkinson’s disease (PD) is the second most common neurodegenerative disease and primarily considered as a movement disorder defined by the presence of motor symptoms, such as bradykinesia, tremor and rigidity. However, it is nowadays widely accepted that PD is associated with a wide variety of non-motor features, which affect the vast majority of patients during the course of the disease and may even precede the onset of motor symptoms. The spectrum of these non-motor disturbances is very broad and comprises neuropsychiatric conditions, such as depression, dementia and hallucinations, as well as autonomic, sensory and sleep disorders. Physicians need to be aware of these non-motor features, since they have substantial impact on the health-related quality of life of PD patients, even ahead of motor symptoms. This article aims to provide an overview of frequently observed non-motor features in PD and discusses prospects and limitations of currently available options for symptomatic treatment of these disturbances.