Neurodegenerative disorders: Are we wrong?

It is not obvious how to define a neurodegenerative disorder. There are several challenging questions: How should the diagnosis be made? How can we be sure that symptoms do not simply reflect normal aging of the nervous system? What are the mechanisms and what are the causes? What are the perspectives of treatment for the patients? Today, given the repetitive failures of curative and preventive treatments, the purpose of the following remarks is not to provide an additional lesson on "how to find a new treatment". Instead, the aim is to ask the difficult questions that might lead to envisaging research from another angle.

Neurostimulation for Parkinson's disease with early motor complications

BACKGROUND

Subthalamic stimulation reduces motor disability and improves quality of life in patients with advanced Parkinson's disease who have severe levodopa-induced motor complications. We hypothesized that neurostimulation would be beneficial at an earlier stage of Parkinson's disease.

METHODS

In this 2-year trial, we randomly assigned 251 patients with Parkinson's disease and early motor complications (mean age, 52 years; mean duration of disease, 7.5 years) to undergo neurostimulation plus medical therapy or medical therapy alone. The primary end point was quality of life, as assessed with the use of the Parkinson's Disease Questionnaire (PDQ-39) summary index (with scores ranging from 0 to 100 and higher scores indicating worse function). Major secondary outcomes included parkinsonian motor disability, activities of daily living, levodopa-induced motor complications (as assessed with the use of the Unified Parkinson's Disease Rating Scale, parts III, II, and IV, respectively), and time with good mobility and no dyskinesia.

RESULTS

For the primary outcome of quality of life, the mean score for the neurostimulation group improved by 7.8 points, and that for the medical-therapy group worsened by 0.2 points (between-group difference in mean change from baseline to 2 years, 8.0 points; P=0.002). Neurostimulation was superior to medical therapy with respect to motor disability (P<0.001), activities of daily living (P<0.001), levodopa-induced motor complications (P<0.001), and time with good mobility and no dyskinesia (P=0.01). Serious adverse events occurred in 54.8% of the patients in the neurostimulation group and in 44.1% of those in the medical-therapy group. Serious adverse events related to surgical implantation or the neurostimulation device occurred in 17.7% of patients. An expert panel confirmed that medical therapy was consistent with practice guidelines for 96.8% of the patients in the neurostimulation group and for 94.5% of those in the medical-therapy group.

CONCLUSIONS

Subthalamic stimulation was superior to medical therapy in patients with Parkinson's disease and early motor complications. (Funded by the German Ministry of Research and others; EARLYSTIM ClinicalTrials.gov number, NCT00354133.).

Segmental progression of early untreated Parkinson's disease: a novel approach to clinical rating

OBJECTIVE

To assess the ability of potentially neuroprotective compounds to slow the progression of Parkinson's disease (PD), sensitive rating scales are needed to detect clinically meaningful effects. The topographical progression of motor signs in early untreated PD was evaluated to complement current clinical ratings and enhance the sensitivity to detect disease progression.

METHODS

12 patients referred for diagnostic evaluation of untreated de novo PD underwent detailed clinical assessment of motor parkinsonian signs at baseline and after 6 and 12 months of follow-up using the Unified Parkinson's Disease Rating Scale, motor part (UPDRS-III), and a newly developed approach of detailed segmental rating taking into account the localisation of motor signs in all of the major joints and muscle groups in the body. The progression of PD, as measured with the UPDRS-III, was compared with the segmental ratings.

RESULTS

UPDRS-III scores and segmental ratings for rigidity and rest and postural tremor, but not bradykinesia, progressed significantly during the observation period. Progression of normalised segmental ratings for rigidity and tremor was significantly larger than the UPDRS-III ratings over 1 year. The segmental ratings for rigidity and tremor as well as their combination with the UPDRS-III bradykinesia rating were more sensitive a measure for progression of PD than the UPDRS-III.

CONCLUSIONS

Taking into account the segmental evolution of parkinsonian signs may be a useful adjunct to UPDRS-III evaluations to measure clinical disease progression of PD. If validated in subsequent larger cohorts, this may be useful in trials of neuroprotective agents.

Effects of nigral stimulation on locomotion and postural stability in patients with Parkinson's disease

The physiopathology of gait and balance disorders in Parkinson's disease patients is still poorly understood. Levodopa treatment and subthalamic nucleus (STN) stimulation improve step length and walking speed, with less effect on postural instability. These disorders have been linked to dysfunction of the descending basal ganglia outputs to brainstem structures. In this study, we evaluated the effects of stimulation of the substantia nigra pars reticulata (SNr), on locomotion and balance in Parkinson's disease patients. Biomechanical parameters and leg muscle activity were recorded during gait initiation in seven selected patients operated for bilateral STN stimulation, out of 204 stimulated patients, with one contact of each electrode located within the SNr. Step length, anteroposterior and vertical velocities of the centre of gravity were studied, with special reference to the subjects' ability to brake the centre of gravity fall before foot-contact, and compared to seven controls. In Parkinson's disease patients, five treatment conditions were tested: (i) no treatment, (ii) levodopa treatment, (iii) STN stimulation, (iv) SNr stimulation and (v) combined levodopa treatment and STN stimulation. The effects of these treatments on motor parkinsonian disability were assessed with the UPDRS III scale, separated into 'axial' (rising from chair, posture, postural stability and gait) and 'distal' scores. Whereas levodopa and/or STN stimulation improved 'axial' and 'distal' motor symptoms, SNr stimulation improved only the 'axial' symptoms. Compared to controls, untreated Parkinson's disease patients showed reduced step length and velocity, and poor braking just prior to foot-contact, with a decrease in both soleus (S) and anterior tibialis (AT) muscle activity. Step length and velocity significantly increased with levodopa treatment alone or in combination with STN stimulation in both natural and fast gait conditions, and with STN stimulation alone in the fast gait condition. Conversely, SNr stimulation had no significant effect on these measures in either condition. In the natural gait condition, no fall in the centre of gravity occurred as step length was low and active braking was unnecessary. In the fast gait condition, braking was improved with STN or SNr stimulation but not with levodopa treatment, with an increase in the stance leg S muscle activity. These results suggest that anteroposterior (length and velocity) and vertical (braking capacity) gait parameters are controlled by two distinct systems within the basal ganglia circuitry, representing respectively locomotion and balance. The SNr, a major basal ganglia output known to project to pontomesencephalic structures, is postulated as being particularly involved in balance control during gait.

A multidisciplinary study of patients with early-onset PD with and without parkin mutations

OBJECTIVE

To establish phenotype-genotype correlations in early-onset Parkinson disease (EOPD), we performed neurologic, neuropsychological, and psychiatric evaluations in a series of patients with and without parkin mutations.

BACKGROUND

Parkin (PARK2) gene mutations are the major cause of autosomal recessive parkinsonism. The usual clinical features are early-onset typical PD with a slow clinical course, an excellent response to low doses of levodopa, frequent treatment-induced dyskinesias, and the absence of dementia.

METHODS

A total of 44 patients with EOPD (21 with and 23 without parkin mutations) and 9 unaffected single heterozygous carriers of parkin mutations underwent extensive clinical, neuropsychological, and psychiatric examinations.

RESULTS

The neurologic, neuropsychological, and psychiatric features were similar in all patients, except for significantly lower daily doses of dopaminergic treatment and greater delay in the development of levodopa-related fluctuations (p < 0.05) in parkin mutation carriers compared to noncarriers. There was no major difference between the two groups in terms of general cognitive efficiency. Psychiatric manifestations (depression) were more frequent in patients than in healthy single heterozygous parkin carriers but did not differ between the two groups of patients.

CONCLUSION

Carriers of parkin mutations are clinically indistinguishable from other patients with young-onset Parkinson disease (PD) on an individual basis. Severe generalized loss of dopaminergic neurons in the substantia nigra pars compacta in these patients is associated with an excellent response to low doses of dopa-equivalent and delayed fluctuations, but cognitive impairment and special behavioral or psychiatric symptoms were not more severe than in other patients with early-onset PD.

[Can subthalamic nucleus stimulation reveal parkinsonian rest tremor?]

INTRODUCTION

Rest tremor, one of the main symptoms in Parkinson's disease (PD), is dramatically improved following subthalamic nucleus stimulation (STN). Results are often better than after l-dopa treatment. The occurrence of rest tremor after neurosurgery in patients without preoperative tremor is uncommon.

AIM

The aim of this work was to investigate the role of subthalamic nucleus stimulation in the appearance of parkinsonian rest tremor. PATIENTS-RESULTS: Thirty PD patients (14%) out of 215 undergoing STN deep brain stimulation had an akinetorigid form of the disease, without preoperative tremor 11 years after onset of the disease. Six of them experienced the appearance of tremor six months after bilateral STN stimulation when the stimulator was switched off in the Off medication state. This de novo parkinsonian tremor was improved by l-dopa treatment and disappeared when the stimulator was turned on.

CONCLUSION

This finding suggests that infraclinical parkinsonian tremor is probably present in all PD patients.

Movement disorders and inborn errors of metabolism in adults: a diagnostic approach

Inborn errors of metabolism (IEMs) may present in adolescence or adulthood with various movement disorders including parkinsonism, dystonia, chorea, tics or myoclonus. Main diseases causing movement disorders are metal-storage diseases, neurotransmitter synthesis defects, energy metabolism disorders and lysosomal storage diseases. IEMs should not be missed as many are treatable. Here we briefly review IEMs causing movement disorders in adolescence and adults and propose a simple diagnostic approach to guide metabolic investigations based on the clinical course of symptoms, the type of abnormal movements, and brain MRI abnormalities.

[Dystonia, tremor and repetitive instrumental use]

Three characteristic observations are presented along with three tables presenting 24 patients with the following elements in common: excessively repeated use of an instrument such as a pen, a musical instrument or a tool. The appearance after that use of a central pathological phenomenon that includes a local dystonia of a hand or the mouth, a tremor, or the association of a tremor and a dystonia, all within the muscular domain corresponding to that of the use. The discussion, which is based exclusively on the clinical findings, deals with the following elements: the role of the use of the instrument rather than task itself, the predominant pathogenic factor which is the repetitive action, to which is added a genetic component in one incompletely penetrant case of DYT 1, and a probable genetic susceptibility in the others. The absence of improvement with rest distinguishes this central pathology from rheumatologic or orthopaedic problems involving repetitive activities. The evolution is slowly declining when the responsible action is continued. This occurs in three stages: a specific disorder involving only the use of the particular instrument, a more enlarged involvement affecting other activities and eventually a dystonia associated with a tremor or a postural tremor always located to the initial area. The therapeutic interventions suggested by the pathologic role of the repetitive movement is: (1) to advise a new training for the instrument that excludes the habitual movement; (2) to advise the patient to vary any newly acquired repetitive movements.

Nerve cell death in degenerative diseases of the central nervous system: clinical aspects

The origin of degenerative diseases of the central nervous system lies in genetic and acquired disorders. Analysis of the clinical characteristics of diseases affecting specific neuronal systems may help us to understand their pathogenesis. The stereotyped symptomatology characteristic of most degenerative diseases results from neuronal death in specific pathways: pyramidal tract and motor neurons in amyotrophic lateral sclerosis, nigrostriatal dopamine system in Parkinson's disease, posterior and lateral columns of the spinal cord in Friedreich's ataxia, etc. This suggests that these neurons are sensitive to pathological processes that are still unknown. Progression of the disease, whether linear or not, is slow, but it is more rapid than similar effects due to ageing. This indicates either that the environmental cause of degeneration (if it exists) is continuously present or that a vital process has been once and for all disrupted, perhaps at the level of the genome, causing insufficient production of essential proteins, or accumulation of eventually toxic metabolites. Symptoms generally appear during adulthood, i.e. after normal differentiation has taken place, and after a considerable number of neurons have already been damaged. The initiation of neuronal death precedes the appearance of the first symptoms.

Subthalamic Stimulation and Neuronal Activity in the Substantia Nigra in Parkinson's Disease

High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for severe forms of Parkinson's disease (PD). To study the effects of high-frequency STN stimulation on one of the main output pathways of the basal ganglia, single-unit recordings of the neuronal activity of the substantia nigra pars reticulata (SNr) were performed before, during, and after the application of STN electrical stimulation in eight PD patients. During STN stimulation at 14 Hz, no change in either the mean firing rate or the discharge pattern of SNr neurons was observed. STN stimulation at 140 Hz decreased the mean firing rate by 64% and the mean duration of bursting mode activity of SNr neurons by 70%. The SNr residual neuronal activity during 140-Hz STN stimulation was driven by the STN stimulation. How the decrease in rate and modification of firing pattern of SNr-evoked neural activity, during high-frequency STN stimulation, contribute to the improvement of parkinsonian motor disability remains to be elucidated.

Dihydropteridine reductase deficiency: Levodopa's long-term effectiveness without dyskinesia

We report an adult patient lacking endogenous synthesis of monoamines (dopamine, serotonin, and catecholamines) due to a severe dihydropteridine reductase (DHPR) deficiency. With levodopa and 5-hydroxytryptophan (5HTP) supplementation, the patient exhibited moderate mental retardation, acute episodes of parkinsonism, and episodes of depression. Despite the use of levodopa from age 3 months, he exhibited no dyskinesia or dopaminergic cell loss as suggested by normal PET imaging of the dopamine transporter.

Neurosurgery at an earlier stage of Parkinson disease: A randomized, controlled trial

BACKGROUND

Stimulation of the subthalamic nucleus is an effective treatment for advanced Parkinson disease (PD) and is currently performed after a mean disease duration of 14 years, when severe motor complications have resulted in marked loss of quality of life. We examined whether surgery at an early stage would maintain quality of life as well as improve motor function.

METHODS

Twenty patients with PD of short duration (time elapsed since first symptom +/- SD: 6.8 +/- 1.0 years) with mild to moderate motor signs (Unified Parkinson's Disease Rating Scale III "off" medication: 29 +/- 12) who responded well to levodopa treatment were included in pairs, matched for age, duration and severity of disease, and impairment in socioprofessional functioning. Patients were prospectively randomized to undergo bilateral subthalamic nucleus stimulation (n = 10) or receive optimized medical treatment (n = 10). Parkinsonian motor scores, quality of life, cognition, and psychiatric morbidity were assessed at inclusion and at 6, 12, and 18 months after randomization.

RESULTS

Quality of life was improved by 24% in surgical and 0% in nonsurgical patients (p < 0.05). After 18 months, the severity of parkinsonian motor signs "off" medication, levodopa-induced motor complications, and daily levodopa dose were reduced by 69%, 83%, and 57% in operated patients and increased by 29%, 15%, and 12% in the group with medical treatment only (p < 0.001). Adverse events were mild or transient, and overall psychiatric morbidity and anxiety improved in the surgical group.

CONCLUSIONS

Subthalamic nucleus stimulation should be considered a therapeutic option early in the course of Parkinson disease.

Parkinson's disease with camptocormia

BACKGROUND

Camptocormia is defined as an abnormal flexion of the trunk that appears when standing or walking and disappears in the supine position. The origin of the disorder is unknown, but it is usually attributed either to a primary or a secondary paravertebral muscle myopathy or a motor neurone disorder. Camptocormia is also observed in a minority of patients with parkinsonism.

OBJECTIVE

To characterise the clinical and electrophysiological features of camptocormia and parkinsonian symptoms in patients with Parkinson's disease and camptocormia compared with patients with Parkinson's disease without camptocormia.

METHODS

Patients with parkinsonism and camptocormia (excluding patients with multiple system atrophy) prospectively underwent a multidisciplinary clinical (neurological, neuropsychological, psychological, rheumatological) and neurophysiological (electromyogram, ocular movement recording) examination and were compared with age-matched patients with Parkinson's disease without camptocormia.

RESULTS

The camptocormia developed after 8.5 (SD 5.3) years of parkinsonism, responded poorly to levodopa treatment (20%) and displayed features consistent with axial dystonia. Patients with camptocormia were characterised by prominent levodopa-unresponsive axial symptoms (ie, axial rigidity, gait disorder and postural instability), along with a tendency for greater error in the antisaccade paradigm.

CONCLUSION

We suggest that (1) the salient features of parkinsonism observed in patients with camptocormia are likely to represent a specific form of Parkinson's disease and camptocormia is an axial dystonia and (2) both camptocormia and parkinsonism in these patients might result from additional, non-dopaminergic neuronal dysfunction in the basal ganglia.

Neurosurgery in Parkinson disease: A distressed mind in a repaired body?

OBJECTIVE

To prospectively evaluate the impact of subthalamic nucleus (STN) stimulation on social adjustment in patients with Parkinson disease (PD).

METHODS

Before and 18 to 24 months after bilateral STN stimulation, the authors assessed 29 patients with PD for motor disability, cognition (Mattis dementia rating scale, frontal score), psychiatric morbidity (Mini-5.0.0, MADRS, BAS), quality of life (PDQ-39), social adjustment (Social Adjustment Scale), and psychological status using unstructured in-depth interviews.

RESULTS

Despite marked improvement in parkinsonian motor disability, the absence of significant changes in cognitive status, and improvement of activities of daily living and quality of life by the end of the study, social adjustment did not improve. Several kinds of problems with social adjustment were observed, affecting the patients' perception of themselves and their body, marital situation, and professional life. Marital conflicts occurred in 17/24 couples. Only 9 out of 16 patients who had a professional activity before the operation went back to work after surgery.

CONCLUSION

After STN stimulation, patients experienced difficulties in their relations with themselves, their spouses, their families, and their socio-professional environment. The authors suggest a multidisciplinary psychosocial preparation and follow-up to help patients and their entourage cope with the sudden changes in their existence following successful neurosurgery.

Preservation of cognitive function in dystonia treated by pallidal stimulation

OBJECTIVE

To assess the effects of bilateral pallidal deep brain stimulation (DBS) on mood and cognitive performance in patients with dystonia before surgery (at baseline, while patients received their usual treatment) and 12 months postoperatively (while patients received neurostimulation and their medications) in a multicenter prospective study.

METHODS

Twenty-two patients with primary generalized dystonia were evaluated with tests focused on executive functions. The authors considered the patients' severe disability and selected the following tests: Raven Progressive Matrices 38, Similarities and Arithmetic subtests of the Wechsler Adult Intelligence Scale-R, Grober and Buschke, Wisconsin Card Sorting Test (WCST), verbal fluency, Trail Making Test, and the Beck Depression Inventory. Median age at surgery was 30 years (range = 14 to 54 years), median duration of disease was 18.5 years (range = 4 to 37 years).

RESULTS

Before surgery, no patients showed cognitive decline or depression. The surgical procedure appeared to be benign cognitively. One year after surgery, free recall improved. There was a significant reduction in the number of errors in the WCST. No behavioral or mood changes were found.

CONCLUSIONS

Bilateral pallidal stimulation has a good benefit-to-risk ratio as it did not negatively affect cognitive performance and mood in primary dystonia, while a significant motor improvement was obtained. Moreover, a significant mild improvement in executive functions was observed, which may have been related either to the surgical treatment or to the marked decrease in anticholinergic drugs.

Neurosurgery in Parkinson's disease: the doctor is happy, the patient less so?

Despite the overall excellent outcome of neurosurgery in patients with Parkinson's disease, there is often a contrast between the improvement in motor disability and the difficulties of patients to reintegrate a normal life. In this study, the personal, familial and professional difficulties experienced by patients two years after bilateral high frequency stimulation of the subthalamic nucleus were carefully analyzed. To avoid such socio-familial maladjustment, we strongly suggest taking into consideration the patients' psychological and social context before the operation and during the post-operative follow-up.

Stimulation of the subthalamic nucleus in Parkinson's disease: a 5 year follow up

BACKGROUND

The short term benefits of bilateral stimulation of the subthalamic nucleus (STN) in patients with advanced levodopa responsive Parkinson's disease (PD) are well documented, but long term benefits are still uncertain.

OBJECTIVES

This study provides a 5 year follow up of PD patients treated with stimulation of the STN.

METHODS

Thirty seven consecutive patients with PD treated with bilateral STN stimulation were assessed prospectively 6, 24, and 60 months after neurosurgery. Parkinsonian motor disability was evaluated with and without levodopa treatment, with and without bilateral STN stimulation. Neuropsychological and mood assessments included the Mattis Dementia Rating Scale, the frontal score, and the Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

No severe peri- or immediate postoperative side effects were observed. Six patients died and one was lost to follow up. Five years after neurosurgery: (i) activity of daily living (Unified Parkinson Disease Rating Scale (UPDRS) II) was improved by stimulation of the STN by 40% ("off" drug) and 60% ("on" drug); (ii) parkinsonian motor disability (UPDRS III) was improved by 54% ("off" drug) and 73% ("on" drug); (iii) the severity of levodopa related motor complications was decreased by 67% and the levodopa daily doses were reduced by 58%. The MADRS was unchanged, but cognitive performance declined significantly. Persisting adverse effects included eyelid opening apraxia, weight gain, addiction to levodopa treatment, hypomania and disinhibition, depression, dysarthria, dyskinesias, and apathy.

CONCLUSIONS

Despite moderate motor and cognitive decline, probably due to disease progression, the marked improvement in motor function observed postoperatively was sustained 5 years after neurosurgery.

Tourette's syndrome and deep brain stimulation

In this prospective double blind randomised "N of 1" study, a patient with a severe form of Tourette's syndrome was treated with bilateral high frequency stimulation of the centromedian-parafascicular complex (Ce-Pf) of the thalamus, the internal part of the globus pallidus (GPi), or both. Stimulation of either target improved tic severity by 70%, markedly ameliorated coprolalia, and eliminated self injuries. Severe forms of Tourette's syndrome may benefit from stimulation of neuronal circuits within the basal ganglia, thus confirming the role of the dysfunction of limbic striato-pallido-thalamo-cortical systems in this disorder.

Bilateral deep brain stimulation in Parkinson's disease: a multicentre study with 4 years follow-up

Deep brain stimulation (DBS) is associated with significant improvement of motor complications in patients with severe Parkinson's disease after some 6-12 months of treatment. Long-term results in a large number of patients have been reported only from a single study centre. We report 69 Parkinson's disease patients treated with bilateral DBS of the subthalamic nucleus (STN, n = 49) or globus pallidus internus (GPi, n = 20) included in a multicentre study. Patients were assessed preoperatively and at 1 year and 3-4 years after surgery. The primary outcome measure was the change in the 'off' medication score of the Unified Parkinson's Disease Rating Scale motor part (UPDRS-III) at 3-4 years. Stimulation of the STN or GPi induced a significant improvement (50 and 39%; P < 0.0001) of the 'off' medication UPDRS-III score at 3-4 years with respect to baseline. Stimulation improved cardinal features and activities of daily living (ADL) (P < 0.0001 and P < 0.02 for STN and GPi, respectively) and prolonged the 'on' time spent with good mobility without dyskinesias (P < 0.00001). Daily dosage of levodopa was significantly reduced (35%) in the STN-treated group only (P < 0.001). Comparison of the improvement induced by stimulation at 1 year with 3-4 years showed a significant worsening in the 'on' medication motor states of the UPDRS-III, ADL and gait in both STN and GPi groups, and speech and postural stability in the STN-treated group. Adverse events (AEs) included cognitive decline, speech difficulty, instability, gait disorders and depression. These were more common in patients treated with DBS of the STN. No patient abandoned treatment as a result of these side effects. This experience, which represents the first multicentre study assessing the long-term efficacy of either STN or GPi stimulation, shows a significant and substantial clinically important therapeutic benefit for at least 3-4 years in a large cohort of patients with severe Parkinson's disease.

Treatment of end-of-dose wearing-off in parkinson's disease: stalevo (levodopa/carbidopa/entacapone) and levodopa/DDCI given in combination with Comtess/Comtan (entacapone) provide equivalent improvements in symptom control superior to that of traditional levodopa/DDCI treatment

The aim of this study was to evaluate the efficacy of the new optimised levodopa, Stalevo (levodopa, carbidopa and entacapone) in patients with Parkinson's disease experiencing end-of-dose wearing-off. Treatment with Stalevo was compared to treatment with traditional immediate-release levodopa and dopa-decarboxylase inhibitor (DDCI) formulations along with adjunct entacapone (Comtess/Comtan). A European, open, parallel-group, active treatment-controlled phase IIIb study evaluating 176 patients randomised to switch from their current regimen of levodopa/DDCI to either an equivalent dose of Stalevo or levodopa/DDCI plus entacapone. After 6 weeks, treatments were assessed using the Clinical Global Impression of Change, the Unified Parkinson's Disease Rating Scale and a Motor Fluctuations Questionnaire. Over 70% of patients in both the Stalevo and adjunct entacapone arms felt that they were clinically improved and over 80% experienced a reduction in fluctuations. Although there was no significant difference between Stalevo and levodopa/DDCI plus entacapone with regard to motor improvement and side effects, 81% of patients stated that they preferred treatment with Stalevo compared with taking two separate tablets (i.e. levodopa/DDCI and entacapone). Stalevo was well tolerated and safe when substituted for levodopa DDCI preparations.

Does bilateral stimulation of the subthalamic nucleus aggravate apathy in Parkinson's disease?

OBJECTIVE

High frequency stimulation of the subthalamic nucleus (STN) dramatically decreases motor disability in patients with Parkinson"s disease (PD), but has been reported to aggravate apathy. The aim of this study was to analyse the effect of STN stimulation on motivation and reward sensitivity in a consecutive series of PD patients.

METHODS

Apathy and reward sensitivity (Apathy Scale, Stimulus-Reward Learning, Reversal, Extinction, and Gambling tasks) were assessed in 18 PD patients treated by bilateral STN stimulation ("on" and "off" conditions) compared with 23 matched patients undergoing long term treatment with levodopa ("on" and "off" conditions).

RESULTS

Apathy decreased under both STN stimulation and levodopa treatment, whereas explicit and implicit stimulus reward learning was unchanged.

CONCLUSIONS

Bilateral STN stimulation in PD patients does not necessarily have a negative effect on motivation and reward sensitivity and can even improve apathy provided patients have been appropriately selected for neurosurgery.

Parkinson disease, brain volumes, and subthalamic nucleus stimulation

BACKGROUND

High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced Parkinson disease (PD). The clinical and preoperative predictive factors of the best postoperative outcome have been identified. Radiologic predictive factors were investigated.

METHODS

Forty patients with PD underwent surgery for bilateral STN stimulation. MRI was performed in stereotactic conditions before surgery. Brain parenchyma, caudate nucleus, putamen, pallidum, and red nucleus volumes and the surface of the mesencephalon were measured and normalized as percentages of the intracranial volume. Clinical evaluation was performed 1 month before and 6 months after surgery.

RESULTS

The normalized brain parenchyma volume was lower in patients who were older and had a longer disease duration or a lower frontal score and was not predictive of the postoperative outcome. The residual scores for activities of daily living and parkinsonian motor disability were higher in patients with a smaller normalized mesencephalon. The normalized caudate nucleus volume was predictive of the pre- and postoperative levodopa-equivalent dosage.

CONCLUSIONS

Brain atrophy is not an exclusion criterion for neurosurgery, indicating that patients' neurologic, psychiatric, and neuropsychological characteristics are the best predictive factors for neurosurgery. The fact that a smaller normalized mesencephalon surface was associated with a lower beneficial effect of the subthalamic nucleus stimulation on the parkinsonian motor disability suggests that the normalized mesencephalon surface is a predictive factor of the postoperative outcome.

Causal relation between alpha-synuclein gene duplication and familial Parkinson's disease

The alpha-synuclein gene (SNCA) has been implicated in autosomal dominant forms of Parkinson's disease. We screened 119 individuals from families with this rare form of the disease for SNCA duplications by semiquantitative multiplex PCR. Two patients had duplications, which were confirmed by analysis of intragenic and flanking microsatellite markers. The phenotype in both patients was indistinguishable from idiopathic Parkinson's disease and no atypical features were present, by contrast with reports of families with triplication of the same gene. These results indicate that SNCA is more frequently associated with familial Parkinson's disease than previously thought, and that there is a clear dosage effect according to the number of supernumerary copies of this gene.

Athétose ou dystonie ?

The term athetosis has progressively disappeared from the anglo-saxon literature which considers that athetosis is part of the spectrum of dystonia. These two clinical entities can be distinguished, however. Athetosis can be identified, searching for subtle semiological traits, in particular at the level of the hand. The earlier appearance of athetosis may be result from its onset during the early phases of development of the central nervous system. Despite its rarity, the clinical diagnosis of athetosis is important to consider from a prognostic point of view. Indeed, it results from brain lesions, and is therefore not a hereditary disorder as it may be the case for dystonia, and its evolution is relatively stable. The efficacy of treatments used in patients with dystonia, in particular high frequency pallidal stimulation, remains to be assessed in patients with athetosis. The concept of athetosis is still helpful in clinical practice.

Neurokinin B, Neurotensin, and Cannabinoid Receptor Antagonists and Parkinson Disease

The neuropeptides neurokinin B, neurotensin, and anandamide, the endogenous ligands of NK3, NT1, and CB1 receptors respectively, are known to interact with brain dopaminergic transmission. This study evaluated the effects of these three antagonists of the NK3 (SR 142801), neurotensin (SR 48692), and cannabinoid (SR 141716) receptors on the severity of motor symptoms and levodopa-induced dyskinesias after administration of a single dose of levodopa in 24 patients with Parkinson disease. In this exploratory randomized, double-blind, placebo-controlled study, at the dose used, the drugs tested were well tolerated and could not improve parkinsonian motor disability.

Screening for DJ-1 mutations in early onset autosomal recessive parkinsonism

The DJ-1 gene was identified as responsible for early onset autosomal recessive parkinsonism in two families (PARK7). In this study, after excluding mutations in the parkin gene, the authors screened a large series of early onset autosomal recessive parkinsonism families and consanguineous isolated patients of diverse geographic origins for DJ-1 mutations. No mutations were found. This indicates that PARK7 is not a common locus for early onset autosomal recessive parkinsonism, and that one or more new loci remains to be identified.