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Biomedical subjects

P Krystkowiak

Publications and source records attributed to P Krystkowiak.

At least 19 recordsLinked to original sources
PubMed2006

Improvement of gait by chronic, high doses of methylphenidate in patients with advanced Parkinson's disease.

BACKGROUND: Therapeutic management of gait disorders in patients with advanced Parkinson's disease (PD) can sometimes be disappointing, since dopaminergic drug treatments and subthalamic nucleus (STN) stimulation are more effective for limb-related parkinsonian signs than for gait disorders. Gait disorders could also be partly related to norepinephrine system impairment, and the pharmacological modulation of both dopamine and norepinephrine pathways could potentially improve the symptomatology. AIM: To assess the clinical value of chronic, high doses of methylphenidate (MPD) in patients with PD having gait disorders, despite their use of optimal dopaminergic doses and STN stimulation parameters. METHODS: Efficacy was blindly assessed on video for 17 patients in the absence of L-dopa and again after acute administration of the drug, both before and after a 3-month course of MPD, using a Stand-Walk-Sit (SWS) Test, the Tinetti Scale, the Unified Parkinson's Disease Rating Scale (UPDRS) part III score and the Dyskinesia Rating Scale. RESULTS: An improvement was observed in the number of steps and time in the SWS Test, the number of freezing episodes, the Tinetti Scale score and the UPDRS part III score in the absence of L-dopa after 3 months of taking MPD. The L-dopa-induced improvement in these various scores was also stronger after the 3-month course of MPD than before. The Epworth Sleepiness Scale score fell dramatically in all patients. No significant induction of adverse effects was found. INTERPRETATION: Chronic, high doses of MPD improved gait and motor symptoms in the absence of L-dopa and increased the intensity of response of these symptoms to L-dopa in a population with advanced PD.

Aged↗
PubMed2006

Predominance of the contralateral movement-related activity in the subthalamo-cortical loop.

OBJECTIVE: Abnormal low- and high-frequency oscillatory activities have been linked to abnormal movement control in Parkinson's disease. We aimed to study how low- and high-frequency oscillatory activities are modulated by movement in the contralateral and ipsilateral subcorticocortical loops. METHODS: We studied mu, beta and gamma rhythm event-related desynchronisation (ERD) and synchronisation (ERS) recorded from electrode contacts in the subthalamic nucleus (STN) areas and over the primary sensorimotor (PSM) cortex. RESULTS: Mu and beta ERD/ERS patterns were very similar when comparing PSM cortex and STN areas and very different when comparing contralateral and ipsilateral structures. Beta rhythm ERS was more predominant over contralateral structures than over ipsilateral ones. Gamma rhythm ERS was only recorded from the contralateral STN area (particularly following administration of L-Dopa). For all patients, the best bipolar derivations - as defined by the earliest mu and beta ERD and the strongest beta and gamma ERS - always included the STN electrode contacts that produced the best clinical results. CONCLUSIONS: Movement-related activity is involved in the movement preparation in the contralateral subthalamo-cortical loop and in the movement execution in the bilateral subthalamo-cortical loops. SIGNIFICANCE: Contralateral beta rhythm ERD seemed to be related to bradykinesia of the limb performing the movement.

Cerebral Cortex↗
PubMed2006

Distribution of grey matter atrophy in Huntington's disease patients: a combined ROI-based and voxel-based morphometric study.

The striatum, a subcortical structure, is the principal target of the neurodegenerative process in Huntington's disease (HD). The measurement of striatal atrophy using the bicaudate ratio on CT scanner images has therefore been used for years to assess disease progression, but this measure only takes into account unidimensional changes in the head of the caudate nucleus. Recently, voxel-based morphometry (VBM), which permits automated statistical comparisons of whole-brain MRI images, has been proposed to quantify striatal atrophy. However, VBM was not originally designed to study subcortical structures, and severe deep brain deformations that occur in HD may hamper the automatic processing of VBM. Here, we validate the use of the optimised protocol of VBM to quantify subcortical atrophy in HD by comparing results obtained with this method to those provided by manual segmentation of subcortical structures. We studied 20 patients with early HD and 12 controls matched for age, sex and handedness using an improved T1-weighted sequence that eased grey matter segmentation. Both manual and automated methods evidenced the dorso-ventral gradient of striatal atrophy, a loss of grey matter in the globus pallidus and the thalamus, and similar correlations between clinical scores and subcortical atrophy. Furthermore, we were able to detect with VBM grey matter loss in the substantia nigra, the hypothalamus, the amygdala, the insular cortex and the premotor and sensorimotor cortices. Finally, VBM provided results consistent with previous post mortem results and proved to be a sensitive biomarker capable of correctly managing subcortical distortions throughout HD patients' brains.

Adult↗
PubMed2006

A biomechanical study of gait initiation in Huntington's disease.

BACKGROUND: Akinesia in basal ganglia disorders is essentially defined by delayed movement initiation; the reaction time increases and it becomes difficult (or even impossible) for the subject to initiate movement. A biomechanical study of gait initiation would help evaluate the role of akinesia in early stage Huntington's disease (HD) patients. METHODS: We recorded kinematic, spatiotemporal and angular parameters (using video motion analysis, a force platform and an optoelectronic system) for the first two steps taken by 15 HD patients and 15 gender- and age-matched controls. In order to evaluate the influence of an external cue on gait initiation parameters, we studied two movement paradigms: self-triggered initiation and initiation triggered (cued) by a "beep" sound. We analyzed kinematic, spatiotemporal (the speed, length and duration of the two first steps) and angular parameters (range of joint angles) as well as kinetic data (the trajectory of the centre of pressure (COP); the speed and trajectory of the centre of mass (COM)). RESULTS: HD patients presented akinesia in both externally triggered and self-triggered conditions. Patients had more difficulties with self-triggered gait than with triggered gait. In HD, anticipatory postural adjustments (APAs) were more impaired in self-triggered gait initiation than in cued initiation. Indeed, an alteration in the kinetic parameters revealed a reduction in first step speed in both conditions. Hypokinesia (as assessed by a reduction in the range of angle joints) played an important role in this reduction. CONCLUSION: Akinesia is a major feature of impaired gait initiation in HD. The deficiencies in self-triggered initiation in HD seen here fit with a hypothesis whereby deficient internal cueing can be replaced by an external trigger.

Biomechanical Phenomena↗
PubMed2006

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.

Adolescent↗
PubMed2006

Stimulation of the subthalamic nucleus in Parkinson's disease: cognitive and affective changes are not linked to the motor outcome.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN0 DBS) is a widely performed surgical treatment in PD. However, the relationship between motor results and cognitive/behavioural modifications is unclear. OBJECTIVE: This study investigated the correlation patterns of the motor, cognitive and behavioural consequences of STN DBS with respect to positioning of the active contact. METHODS: Fifty-eight consecutive PD patients having undergone STN DBS were assessed pre-operatively and 12 months after surgery. RESULTS: Motor, cognitive and behavioural results were neither correlated to each other nor linked to the position of the active contact. Three patients with a history of pre-operative, dopaminergic psychosis or post-surgical confusion became demented. Age and a distant history of depression were associated with the occurrence of post-surgical depression. CONCLUSION: Correct screening of patients for STN DBS remains an important issue, since the current implantation procedure is not able to take account of potential functional heterogeneity within the target.

Affect↗
PubMed2006

Gait abnormalities induced by acquired bilateral pallidal lesions: a motion analysis study.

BACKGROUND: Bilateral pallidal lesions induce a range of cognitive and motor disorders, principally a parkinsonian syndrome in which severe disturbances of gait and gait initiation are frequently reported. However, the precise clinical features of these disorders (and the role of the pallidum therein) remain to be established. OBJECTIVES: The goal of this study was to characterise gait and gait initiation disorders within the context of a parkinsonian syndrome in patients with acquired, bilateral, pallidal lesions (PAL patients), to compare these disorders to those seen in Parkinson's disease (PD), and to assess the corresponding physiopathological implications. PATIENTS AND METHODS: By using a video motion analysis system (VICON), we studied gait kinematic parameters in two patients presenting with bilateral, pallidal lesions. Kinematic and kinetic parameters were also determined during gait initiation. The two patients were compared with a group of 17 PD patients and to 20 healthy controls. RESULTS: In both PAL and PD patients, kinematic parameters (gait and gait initiation) and kinetic parameters (gait initiation) were similarly impaired, evidenced by akinesia (difficulty in initiating gait characterized by impairment of anticipatory postural adjustments). Hypokinesia and bradykinesia (respectively reduced stride length and reduced speed during gait) were also noted. CONCLUSION: The gait and gait initiation disorders seen in cases of bilateral pallidal lesions (namely akinesia, hypokinesia and bradykinesia) are similar to those observed in PD. Subject to confirmation in more extensive studies, we hypothesize that bipallidal patients may present higher level gait disorders,with potential mediation by cognitive impairment.

Aged↗
PubMed2006

[Differences in anticipatory postural adjustments between self-generated and triggered gait initiation in 20 healthy subjects].

OBJECTIVE: Preparation of upper-limb movements differs between self-paced and triggered conditions. This study analyzed the anticipatory postural adjustments (APAs) of gait initiation in normal subjects in 2 conditions: self-generated and triggered by a "beep" sound. METHODS: We recorded kinematic, spatiotemporal parameters of the first two steps by means of video motion analysis (6 infrared cameras), and kinetic parameters (using a force platform and the optoelectronic system) in 20 normal subjects. Two conditions: 1) self-generated initiation; and 2) initiation triggered by a "beep" sound were studied to evaluate the APA phase, by recording kinetic data (duration of the APAs, trajectory of the center of pressure, speed and trajectory of the center of mass). Kinematic data (first and second step speed, length and duration) were also recorded. RESULTS: First step speed and length were increased in self-paced gait initiation compared to triggered gait initiation in controls. We found no difference between the 2 conditions in terms of second step kinematic data. It was caused by a significant difference between the 2 conditions for the temporal characteristics of anticipatory postural adjustments (APAs) in the initiation of the first step, which was longer when normal subjects performed self-generated gait initiation. The trajectory of center of pressure and center of mass remained the same in the 2 conditions. CONCLUSION: APAs of gait initiation process are delayed under self-paced condition, although they do not differ qualitatively between reaction time and self-paced condition. Neuphysiological support of self-generated movement could explain these differences.

Acoustic Stimulation↗
PubMed2006

Clinical and economic results of bilateral subthalamic nucleus stimulation in Parkinson's disease.

BACKGROUND: High frequency stimulation of the subthalamic nucleus (STN) is an alternative but expensive neurosurgical treatment for parkinsonian patients with levodopa induced motor complications. OBJECTIVE: To assess the safety, clinical effects, quality of life, and economic cost of STN stimulation. METHODS: We conducted a prospective multicentre study in 95 consecutive Parkinson's disease (PD) patients receiving bilateral STN stimulation and assessed its effects over 12 months. A double blind randomised motor evaluation was carried out at 3 month follow up, and quality of life, self care ability, and predictive factors of outcome following surgery were assessed. The cost of PD was estimated over 6 months before and after surgery. RESULTS: The Unified Parkinson's Disease Rating Scale (UPDRS) motor score improved by 57% (p<0.0001) and activities of daily living improved by 48% (p<0.0001) at 12 month follow up. Double blind motor scoring improved by 51% at 3 month follow up (p<0.0001). The total PD Quality of Life Questionnaire (PDQL-37) score improved by 28% (p<0.001). The better the preoperative motor score after a levodopa challenge, the better the outcome after STN stimulation. Five patients developed an intracerebral haematoma during electrode implantation with permanent after effects in two. The 6 month costs of PD decreased from 10,087 euros before surgery to 1673 euros after surgery (p<0.0001) mainly because of the decrease in medication. These savings allowed a return on the procedure investment, estimated at 36,904 euros over 2.2 years. CONCLUSIONS: STN stimulation has good outcomes with relatively low risk and little cost burden in PD patients with levodopa induced motor complications.

Activities of Daily Living↗
PubMed2004

Statistical tools for clinical gait analysis.

Gait analysis studies involve continuous curves of data measured over a gait cycle. Curve analysis and interpretation require adequate statistical methods. Three principal problems may be encountered in clinical practice: (i) the reliability of gait curves for a given patient, (ii) classifying a new subject as belonging to a given population or not and (iii) comparison of two populations (independent or paired). This paper presents three statistical tools for solving these problems: (i) intra-class correlation coefficients, (ii) confidence bands for a population (iii) a combination of analysis of variance and confidence bands for the difference between the means and shows how they can be used in clinical practice.

Adult↗
PubMed2004

[Usefulness and limitations of polymygraphic recordings in dystonia].

INTRODUCTION: Diagnosis of dystonia is based on well-known clinical findings, but electrophysiological explorations can help to establish the diagnosis. METHODS: We report 179 patients presenting primary or secondary dystonia. Polymyographic recordings were available for all. We studied activation patterns of agonist and antagonists muscles (prolonged bursts, co-contraction), presence of antagonistic gestures and other associated movement disorders such as tremor or myoclonus. RESULTS: 83.9 percent of patients presented abnormalities which evoked dystonia (prolonged bursts: 75.3 percent, co-contraction: 48.7 percent, successful antagonistic gesture successful with reduction or suppression of EMG activity, 8.7 percent). For the patients who presented no EMG abnormality, diagnosis was maintained in 22 cases because of the limitations of the exploration: intermittent symptoms, dystonia involving deep muscles which were not recorded by the surface electromyogram, or difficulties to reproduce the conditions of apparition of the dystonic symptoms during examination or to recognize a pathologic EMG pattern in hand cramps for instance. Another diagnosis was retained because of the polymyographic findings in 16.2 p.cent of these patients, particularly those who had tremor associated with dystonia (essentially diagnosis of primary writing tremor). CONCLUSION: Polymyography is an effective tool for confirming clinical findings.

Adult↗
PubMed2004

Subthalamic nucleus stimulation induces deficits in decoding emotional facial expressions in Parkinson's disease.

BACKGROUND: Bilateral subthalamic nucleus (STN) stimulation is recognised as a treatment for parkinsonian patients with severe levodopa related motor complications. Although adverse effects are infrequent, some behavioural disturbances have been reported. OBJECTIVE: To investigate the consequences of STN stimulation on emotional information processing in Parkinson's disease by assessing the performance of an emotional facial expression (EFE) decoding task in a group of patients before and after surgery. METHODS: 12 non-demented patients with Parkinson's disease were studied. They were assessed one month before surgery and three months after. Their ability to decode EFEs was assessed using a standardised quantitative task. Overall cognitive function, executive function, visuospatial perception, depression, and anxiety were also measured. Twelve healthy controls were matched for age, sex, and duration of education. RESULTS: Before surgery, the patients showed no impairment in EFE decoding compared with the controls. Their overall cognitive status was preserved but they had a moderate dysexecutive syndrome. Three months after surgery, they had significant impairment of EFE decoding. This was not related to their overall cognitive status or to depression/anxiety scores. Visuospatial perception was not impaired. There was no change in the extent of the dysexecutive syndrome except for a reduction in phonemic word fluency. CONCLUSIONS: Bilateral STN stimulation disturbs negative emotional information processing in Parkinson's disease. The impairment appears specific and unrelated to certain secondary variables. This behavioural complication of STN may have implications for the patient's social life.

Affect↗
PubMed2003

[Clinical and electrophysiological features of "cortical tremor"].

The purpose of this paper is to draw attention to one particular variant of tremor named "cortical tremor," which corresponds to rhythmic cortical myoclonus whose principal differential diagnosis is essential tremor. Diagnosis may be established with electrophysiological explorations (electromyography, accelerometry, electroencelography with back averaging, long latency reflexes, giant somesthesic evoked potentials). Clinical and electrophysiological features of 15 patients are reported and compared to cases previously published. Association with generalized or partial seizures is possible. Other cases in the family are often mentioned with a dominant autosomal transmission. The therapeutic approach is based on the use of antiepileptic drugs.

Adolescent↗
PubMed2001

Chronic bilateral pallidal stimulation and levodopa do not improve gait in the same way in Parkinson's disease: a study using a video motion analysis system.

Chronic bilateral internal globus pallidus (GPi) stimulation allows control of levodopa induced dyskinesias (LID) and motor symptoms in severe Parkinson's disease (PD). The effect on gait has not been clearly established. Different results have been reported, mostly consisting of clinical data. The aim of this study was to evaluate, by means of a video motion analysis system (optoelectronic VICON system), the influence of bilateral GPi stimulation on gait in PD. Five patients underwent bilateral GPi stimulation. The preoperative and postoperative (3 months after surgery) clinical gait disturbances (items 29 and 30 of the motor UPDRS), as well as spatial and temporal gait measurements (namely cadence, velocity, stride and step times, single and double limb support times, stride and step lengths) were analysed in off condition (the patient had received no treatment for 12 hours or merely the lowest dose of levodopa allowing him to walk for the gait analysis) and in the on drug condition (after administration of 200 mg of levodopa). The gait analysis was performed with the VICON system. In off condition, there was a statistically significant improvement after surgery for UPDRS III and gait (clinically assessed). In on drug condition, there was a significant improvement for LID whereas UPDRS III and clinical assessment of gait were unchanged. The VICON system also showed that surgery improved gait especially in off condition, but also in on drug condition. Our method allowed exact quantification of the influence of surgery on gait characteristics. As compared with levodopa treatment, the effect of stimulation seems to be different. Indeed, the results suggest only limited effects of pallidal stimulation on the control of stride length and rather point to compensatory additional mechanisms.

Aged↗
PubMed2001

Influence of chronic bilateral stimulation of the subthalamic nucleus on cognitive function in Parkinson's disease.

BACKGROUND: The clinical efficacy of chronic deep brain stimulation in the treatment of parkinsonian patients with severe levodopa-related motor adverse effects has been repeatedly shown. Bilateral subthalamic nucleus (STN) stimulation has been shown to present an advantage over pallidal stimulation as it induces a higher antiakinetic effect and has positive effects on all parkinsonian symptoms. The morbidity of such surgery is usually considered to be very low. However, few studies have extensively examined the effects of chronic STN stimulation on cognitive function. OBJECTIVE: The aim of the present study was to assess the effects of chronic bilateral STN stimulation on performance in an extensive battery of neuropsychological tests, three months and one year after surgery. METHODS: Nine patients with Parkinson's disease were selected for STN electrodes implantation. They underwent a neuropsychological evaluation at one month before and at three months after surgery. Six of them were examined again at one year after surgery. RESULTS: Before surgery, no patient showed cognitive decline. At three months after surgery, no modification was observed for most tasks. The information processing speed tended to improve. There was a significant reduction of the performance in a delayed free recall test and a trend toward a significant reduction of categorial word fluency. At one year after surgery, most task measures did not change. Slight impairment was observed for tasks evaluating executive function. Examination of individual results showed that some patients (30% at 3 months after surgery) showed an overall cognitive decline. Behavioural changes were also observed in 4 patients with overall cognitive decline in one of them. CONCLUSION: In general, STN deep brain stimulation can be considered as a significant contribution to the treatment of severe Parkinson's disease However, in some patients it can induce overall cognitive decline or behavioural changes.

Cognition Disorders↗