Aberrant resting-state oscillatory brain activity in Parkinson's disease patients with visual hallucinations: An MEG source-space study.

To gain insight into possible underlying mechanism(s) of visual hallucinations (VH) in Parkinson's disease (PD), we explored changes in local oscillatory activity in different frequency bands with source-space magnetoencephalography (MEG). Eyes-closed resting-state MEG recordings were obtained from 20 PD patients with hallucinations (Hall+) and 20 PD patients without hallucinations (Hall-), matched for age, gender and disease severity. The Hall+ group was subdivided into 10 patients with VH only (unimodal Hall+) and 10 patients with multimodal hallucinations (multimodal Hall+). Subsequently, neuronal activity at source-level was reconstructed using an atlas-based beamforming approach resulting in source-space time series for 78 cortical and 12 subcortical regions of interest in the automated anatomical labeling (AAL) atlas. Peak frequency (PF) and relative power in six frequency bands (delta, theta, alpha1, alpha2, beta and gamma) were compared between Hall+ and Hall-, unimodal Hall+ and Hall-, multimodal Hall+ and Hall-, and unimodal Hall+ and multimodal Hall+ patients. PF and relative power per frequency band did not differ between Hall+ and Hall-, and multimodal Hall+ and Hall- patients. Compared to the Hall- group, unimodal Hall+ patients showed significantly higher relative power in the theta band (p = 0.005), and significantly lower relative power in the beta (p = 0.029) and gamma (p = 0.007) band, and lower PF (p = 0.011). Compared to the unimodal Hall+, multimodal Hall+ showed significantly higher PF (p = 0.007). In conclusion, a subset of PD patients with only VH showed slowing of MEG-based resting-state brain activity with an increase in theta activity, and a concomitant decrease in beta and gamma activity, which could indicate central cholinergic dysfunction as underlying mechanism of VH in PD. This signature was absent in PD patients with multimodal hallucinations.

[The opsoclonus-myoclonus syndrome]. / Opsoclonus-myoclonussyndroom.

The opsoclonus-myoclonus syndrome (OMS) was diagnosed in nine patients, two men and seven women, varying in age from 34 to 65 years. In two cases the findings indicated a post-infectious form, in three cases there was a malignancy, in one case there was a connection with the use of medication and in three cases the cause was unknown. OMS is a rare neurological disorder with symptoms of rapid, involuntary saccadic eye movements (opsoclonus) and sudden involuntary muscle contractions (myoclonus). It has been associated with infections, malignancies, intoxications and metabolic disorders. In 50% of the cases no cause can be identified. There is evidence for dysfunction ofbrainstem and cerebellar pathways and in many cases an (auto-)immune process is implied. Once the diagnosis has been established, screening for occult malignancy is indicated. The prognosis of idiopathic and post-infectious OMS is generally good and the treatment is mainly supportive.

[The first patient with the new variant of Creutzfeldt-Jakob's disease in The Netherlands]. / De eerste patiënt in Nederland met de nieuwe variant van de ziekte van Creutzfeldt-Jakob.

A Dutch woman died at the age of 26 years, after a disease duration of 18 months, due to the new variant of Creutzfeldt-Jakob's disease (vCJD). She had never travelled to the United Kingdom and there was no history of potential iatrogenic exposure. However, she had worked in the catering and food production industry for the previous 6 years and had frequently consumed raw meat. The disease course showed the classical clinical picture of vCJD, which was confirmed by post-mortem examination of the brain. Contrary to classical sporadic CJD, patients with the variant disease are usually younger and present predominantly with psychiatric symptoms. Sensory complaints like pain and dysaesthesiae usually follow soon. Only later are these symptoms followed by rapidly progressive neurological symptoms and signs. All patients genotyped so far are homozygous for methionine on codon 129 of the prion protein gene. Recognition of the disease is of particular importance because of possible transmission via blood and tissues. In patients with rapidly progressive psychiatric symptoms and unexplained neurological signs, particularly sensory complaints, one must consider the possibility of vCJD.

Accuracy of objective ambulatory accelerometry in detecting motor complications in patients with Parkinson disease.

Shortcomings of existing assessment methods in Parkinson disease (PD) have led to the development of continuous ambulatory multichannel accelerometry for the assessment of the core features of PD. Although measures for hypokinesia, bradykinesia, and tremor have been validated in groups of patients with PD, it is unclear whether this method is able to detect "on" with or without dyskinesias, and "off" in individual PD patients. This study therefore addressed the accuracy of objective ambulatory accelerometry in detecting motor complications in 15 PD patients, using a self-assessment scale as gold standard. Measures for hypokinesia, bradykinesia, and tremor showed limited sensitivity (0.60-0.71) and specificity (0.66-0.76) for motor complications in individual PD patients. In the group of PD patients, comparing the "on" with the "off" state yielded statistically significant differences for tremor only. Objective dyskinesia measures correlated with time spent with dyskinesias (r = 0.89). Although validated for the measurement of hypokinesia, bradykinesia, and tremor, continuous ambulatory multichannel accelerometry currently cannot detect "on" and "off" in individual PD patients.

Ambulatory objective assessment of tremor in Parkinson's disease.

Continuous ambulatory multichannel accelerometry (CAMCA) has recently been validated for the assessment of hypo-and bradykinesia and body position in patients with Parkinson's disease (PD). This study aims to validate CAMCA for the assessment of resting tremor in patients with PD. First, in seven patients with PD with varying degrees of tremor severity, a tremor detection algorithm was developed. Second, 59 patients with PD and 43 age-matched controls were assessed with CAMCA during 24 hours. Duration and intensity of resting tremor, and measures reflecting hypo-and bradykinesia and body position were calculated for the diurnal period. In part 1 of the study, the tremor detection algorithm had a high sensitivity (0.82) and specificity (0.93). Ambulatory monitoring revealed that categories with higher clinical tremor severity had increased objective values for duration and intensity of tremor. Duration and intensity of tremor were correlated with the clinical score for resting tremor (Spearman's rank correlation: 0.66-0.77). Measures for hypo-and bradykinesia differed between patients and controls, but not between groups of patients defined by tremor severity. This study has validated continuous ambulatory multichannel accelerometry for the assessment of tremor in PD, while simultaneously measuring hypo-and bradykinesia and body position.

Accelerometric assessment of levodopa-induced dyskinesias in Parkinson's disease.

Our objective was to develop parameters for objective ambulatory measurements of levodopa-induced dyskinesias (LID) in patients with Parkinson's disease (PD). Twenty-three PD patients with mild to severe LID were submitted to a standardized protocol of 1-minute recordings during rest, talking, stress, and four activities of daily life (ADL). Patients were simultaneously monitored with portable multi-channel accelerometry (four pairs of bi-axial sensors mounted onto the most affected arm, leg, and at the trunk) and recorded by video. LID severity was assessed with a modified Abnormal Involuntary Movement Scale (m-AIMS). The signals were analyzed, and every 1/8-second interval the amplitude was obtained of the dominant frequency within 1-4 Hz and 4-8 Hz frequency bands (Amp1-4 and Amp4-8). For both measures, convergent validity, reproducibility, and responsiveness were determined. In absence of voluntary movements, a significant relation was found between Amp1-4 and Amp4-8 and m-AIMS. Repeated measurements during rest showed a high reproducibility (intraclass correlation coefficient = 0.90 [Amp1-4] and 0.86 [Amp4-8]). The extent to which LID increased with talking and stress correlated significantly (p = 0.02) between the objective and clinical measures (intraclass correlation for differences = 0.67). During ADL, LID occurred in a similar frequency band as voluntary movements and only Amp1-4 and Amp4-8 of the trunk and leg sensor remained highly correlated with m-AIMS. Although objective measures of LID are reliable and responsive, they fail to distinguish LID from voluntary movements. These measures are of value only when obtained during rest (all sensor sites) or during ADL when derived from those body segments that are normally not involved in these ADL tasks (trunk and leg).

Detection and assessment of the severity of levodopa-induced dyskinesia in patients with Parkinson's disease by neural networks.

Levodopa-induced dyskinesias (LID) in Parkinson's disease (PD) have remained a clinical challenge. We evaluated the feasibility of neural networks to detect LID and to quantify their severity in 16 patients with PD at rest and during various activities of daily living. The movements of the patients were measured using four pairs of accelerometers mounted on the wrist, upper arm, trunk, and leg on the most affected side. Using parameters obtained from the accelerometer signals, neural networks were trained to detect and to classify LID corresponding to the modified Abnormal Involuntary Movement Scale. Important parameters for classification appeared to be the mean segment velocity and the cross-correlation between accelerometers on the arm, trunk, and leg. Neural networks were able to distinguish voluntary movements from LID and to assess the severity of LID in various activities. Based on the results in this study, we conclude that neural networks are a valid and reliable method to detect and to assess the severity of LID corresponding to the modified Abnormal Involuntary Movement Scale.

Intrathecal baclofen for the treatment of dystonia in patients with reflex sympathetic dystrophy.

BACKGROUND AND METHODS: Patients with reflex sympathetic dystrophy (also known as the complex regional pain syndrome) may have dystonia, which is often unresponsive to treatment. Some forms of dystonia respond to the intrathecal administration of baclofen, a specific gamma-aminobutyric acid-receptor (type B) agonist that inhibits sensory input to the neurons of the spinal cord. We evaluated this treatment in seven women who had reflex sympathetic dystrophy with multifocal or generalized tonic dystonia. First, we performed a double-blind, randomized, controlled crossover trial of bolus intrathecal injections of 25, 50, and 75 microg of baclofen and placebo. Changes in the severity of dystonia were assessed by the woman and by an investigator after each injection. In the second phase of the study, six of the women received a subcutaneous pump for continuous intrathecal administration of baclofen and were followed for 0.5 to 3 years. RESULTS: In six women, bolus injections of 50 and 75 microg of baclofen resulted in complete or partial resolution of focal dystonia of the hands but little improvement in dystonia of the legs. During continuous therapy, three women regained normal hand function, and two of these three women regained the ability to walk (one only indoors). In one woman who received continuous therapy, the pain and violent jerks disappeared and the dystonic posturing of the arm decreased. In two women the spasms or restlessness of the legs decreased, without any change in the dystonia. CONCLUSIONS: In some patients, the dystonia associated with reflex sympathetic dystrophy responds markedly to intrathecal baclofen.

Clinimetric issues of screening for responsiveness to intrathecal baclofen in dystonia.

OBJECTIVES: In this study we address clinimetric issues that pertain to the screening of responsiveness to intrathecal baclofen (ITB) in dystonia. METHODS: Eight patients with severe dystonia, who did not respond to oral medication, were evaluated in a double-blind placebo controlled ascending dose screening procedure, which included a randomised sequence of injections of 25, 50 and 75 microg baclofen and placebo. Self-assessments of dystonia severity on a visual analogue scale (VAS) and the Dyskinesia Rating Scale (DRS) were carried out at baseline 1, 4 and 8 hours after a bolus injection. RESULTS: Compared to the VAS, the DRS lacked responsiveness in all patients. Baseline scores of the VAS scores varied considerably between and within patients and underscore the need to express response scores in relation to the baseline. After placebo administration some patients showed a persistent improvement of about 30% across the day, while at some assessments improvements of >50% were noted. Based on the aforementioned findings, a responsiveness coefficient was used which relates the baclofen effect size to the non-specific score changes that may occur as a placebo effect or as random fluctuations in dystonia. Four patients with a responsiveness coefficient >2 received pump implantation and did well on continuous infusion of ITB. Several side effects occurred during the screening procedure, but none interfered with the execution of the screening procedure. CONCLUSIONS: This study demonstrates important clinimetric issues that need to be taken into account when screening for responsiveness to ITB.

A review of the assessment of dyskinesias.

Dyskinesias are most prevalent in patients with Huntington's disease (HD), patients with Parkinson's disease (PD) who have received chronic levodopa therapy, and in patients who have been treated with neuroleptics (tardive dyskinesia ITD]). Recent therapeutic developments have fueled a growing interest in the clinimetrics of dyskinesias. For dyskinesias in HD, few rating scales are available, but data on validity, reliability, and responsiveness are scarce. Only the interrater reliability of facial dyskinesias has been evaluated and found to be low. Many subjective rating scales for dyskinesias in PD exist, but only the Dyskinesia Rating Scale has undergone sufficient clinimetric evaluation. For TD, numerous rating scales are available, many of them with ample data on reliability and validity. Objective assessment of dyskinesias has been attempted with a number of techniques. All these methods require a laboratory setting, rendering them susceptible to influence of stress. Moreover, they provide only a momentary assessment of dyskinesia severity and fail to take into account diurnal fluctuations. In view of the methodologic shortcomings in the assessment of dyskinesias, more effort needs to be put into strengthening currently available modes of assessment or designing new ones. In the future ambulatory accelerometry might prove to be of value in this field.

Ambulatory quantitative assessment of body position, bradykinesia, and hypokinesia in Parkinson's disease.

We used ambulatory monitoring to quantify body position, bradykinesia, and hypokinesia simultaneously in 50 patients with Parkinson's disease (PD) and 43 healthy elderly during the diurnal period. Reliable automatic detection of three defined body positions proved possible. As compared with controls, PD patients spent less time upright and more time during the day lying down, which correlated well with the self-reported time spent lying down. PD patients had significantly lower mean values of extremity acceleration and higher mean values of immobility than controls. The objective measures of bradykinesia and hypokinesia showed only a modest or no relation to the semiquantitative subjective Unified Parkinson's Disease Rating Scale (UPDRS) motor scores, which most likely was due to differences between the methods. In contrast to bradykinesia measures, hypokinesia measures showed clear sex differences in both patients and controls. Over time, trunk and arm movements occurred more frequently in women than in men. Our ambulatory monitoring assessment disclosed clinically relevant information about the mobility profile and offers a way to quantify cardinal movement features simultaneously in PD patients throughout the day.

Fatigue in Parkinson's disease is not associated with reduced physical activity.

We evaluated whether the self-reported reduction of physical activity associated with fatigue in Parkinson's disease (PD) could be quantified with a wrist-worn activity monitor in 69 non-depressed PD patients. A questionnaire was used to assess the presence of fatigue. Outcome measures reflected activity, immobility and sustained activity above preset thresholds. Thirty PD patients suffering from fatigue did not differ from 39 PD patients (with similar disease severity) who were not suffering from fatigue. These results emphasize the need to explore the role of the mental aspects of fatigue in PD.

Sleep disruption in Parkinson's disease. Assessment by continuous activity monitoring.

OBJECTIVE: To assess differences in activity and immobility during sleep between patients with Parkinson's disease (PD) and healthy subjects and to evaluate the relations of clinical variables with the motor activity measures in patients with PD. DESIGN: Survey, case series. SETTING: University hospital outpatient neurology department and urban population in Leiden, the Netherlands. Motor activity was recorded during 6 successive nights at home with a wrist-worn activity monitor. PARTICIPANTS: Eighty-nine patients with PD and 83 age-matched healthy controls. MAIN OUTCOME MEASURES: For each subject, three mean measures reflecting activity or immobility during the nocturnal period were calculated. RESULTS: Compared with the healthy elderly subjects, patients with PD have an elevated nocturnal activity level and an increased proportion of time with movement, indicating a more disturbed sleep. The mean duration of nocturnal immobility periods was similar for both groups. This measure, however, did reflect the self-reported disturbed sleep maintenance in both groups. The daily dose of levodopa or the use of dopamine agonists in patients not receiving levodopa, rather than disease severity, proved to be the best predictors of nocturnal activity. CONCLUSIONS: We hypothesize that in mildly to moderately affected patients with PD, levodopa or dopamine agonists cause sleep disruption by their effects on sleep regulation. In more severely affected patients, the beneficial effects of these drugs on nocturnal disabilities that cause sleep disruption in PD prevail.

Motor effects of the partial dopamine agonist (-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine (preclamol) in Parkinson's disease.

The motor effects of the partial dopamine agonist (-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine [(-)-3-PPP, preclamol] were evaluated in nine patients with Parkinson's disease using a double-blind, placebo-controlled design. (-)-3-PPP monotherapy had an antiparkinsonian effect in five of nine patients at a mean dose of 37 +/- 10 mg intramuscularly. The co-administration of (-)-3-PPP and a mildly dyskinetic dose of levodopa, infused intravenously at steady-state, resulted in complete suppression of dyskinesias and reemergence of parkinsonian signs in two of seven patients. These dopamine antagonist effects of (-)-3-PPP occurred at relatively low (2.5 and 5 mg) doses. Our results suggest that partial dopamine agonists can exert agonist or antagonist activity in parkinsonian patients depending on concurrent dopaminergic tone. Although this dual action of (-)-3-PPP and other partial agonists could be therapeutically important on theoretical grounds, the small number of patients manifesting a clinically significant response and the frequently inconsistent effects could indicate that this class of agents may have relatively limited clinical utility.

The clinimetrics of hypokinesia in Parkinson's disease: subjective versus objective assessment.

In this study we evaluate the feasibility of measures that reflect different characteristics of motor activity and immobility in the objective quantification of hypokinesia. Because by definition hypokinesia can only be assessed over a period of time, continuous activity monitoring was used during 5 successive days in the home setting in 64 patients with Parkinson's disease (PD) and 104 healthy elderly subjects. In the patients we also evaluated the relation between the monitor measures and subjective measures of hypokinesia and age. Compared to the healthy elderly subjects, PD patients have a decreased activity level, increased proportion of time without movement, elevated mean duration of immobility, and decreased percentage of short-lasting immobility periods. Differences between both groups were most prominent for those measures that incorporate or reflect immobility. Moreover, in the PD patients the mean duration of immobility and percentage of short-lasting immobility periods show an apparent lack of relation with age and clinical ratings obtained from the UPDRS. In conclusion, our findings underscore the poor representation of hypokinesia in the UPDRS and value of objective quantification of this fundamental impairment of PD.