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Helmich RC, Snijders AH, Verkes RJ, Bloem BR. [Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 2004; 148:410-5. [PMID: 15038199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The changes occur locally as well as at a distance in functionally connected brain areas. These features render rTMS a suitable tool to study normal brain functions and the pathophysiology of brain diseases. Furthermore, it is expected that rTMS could be used as a novel therapy for neurological or psychiatric diseases characterised by abnormal cortical activation. This possibility has been studied mostly in patients suffering from depression, where rTMS has been used to restore normal activity in the hypoactive prefrontal cortex. Despite statistically significant therapeutic effects in small sized trials, the clinical implications are still limited.
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van Iersel MB, Hoefsloot W, Munneke M, Bloem BR, Olde Rikkert MGM. Systematic review of quantitative clinical gait analysis in patients with dementia. Z Gerontol Geriatr 2004; 37:27-32. [PMID: 14991293 DOI: 10.1007/s00391-004-0176-7] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2003] [Accepted: 06/13/2003] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Diminished mobility often accompanies dementia and has a great impact on independence and quality of life. New treatment strategies for dementia are emerging, but the effects on gait remains to be studied objectively. In this review we address the general effects of dementia on gait as revealed by quantitative gait analysis. METHODS A systematic literature search with the (MESH) terms: 'dementia' and 'gait disorders' in Medline, CC, Psychlit and CinaHL between 1980-2002. Main inclusion criteria: controlled studies; patients with dementia; quantitative gait data. RESULTS Seven publications met the inclusion criteria. All compared gait in Alzheimer's Disease (AD) with healthy elderly controls; one also assessed gait in Vascular Dementia (VaD). The methodology used was inconsistent and often had many shortcomings. However, there were several consistent findings: walking velocity decreased in dementia compared to healthy controls and decreased further with progressing severity of dementia. VaD was associated with a significant decrease in walking velocity compared to AD subjects. Dementia was associated with a shortened step length, an increased double support time and step to step variability. DISCUSSION Gait in dementia is hardly analyzed in a well-designed manner. Despite this, the literature suggests that quantitative gait analysis can be sufficiently reliable and responsive to measure decline in walking velocity between subjects with and without dementia. More research is required to assess, both on an individual and a group level, how the minimal clinically relevant changes in gait in elderly demented patients should be defined and what would be the most responsive method to measure these changes.
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Bloem BR, Munneke M, Carpenter MG, Allum JHJ. The impact of comorbid disease and injuries on resource use and expenditures in parkinsonism. Neurology 2003; 61:1023; author reply 1023-4. [PMID: 14557594 DOI: 10.1212/01.wnl.0000082160.30833.50] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Bloem BR, Roofthooft DW, Lammers GJ, de Beaufort AJ, Brouwer OF. [Withdrawal symptoms in a neonate following exposure to venlafaxine during pregnancy]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 2003; 147:1885-6; author reply 1886. [PMID: 14533505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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Helmich RCG, Bäumer T, Bloem BR, Münchau A. Die Somatotopie der senso-motorischen Integration ist körpersegmentspezifisch nicht jedoch muskelspezifisch. KLIN NEUROPHYSIOL 2003. [DOI: 10.1055/s-2003-816449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Schlaghecken F, Münchau A, Bloem BR, Rothwell J, Eimer M. Slow frequency repetitive transcranial magnetic stimulation affects reaction times, but not priming effects, in a masked prime task. Clin Neurophysiol 2003; 114:1272-7. [PMID: 12842725 DOI: 10.1016/s1388-2457(03)00118-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Slow frequency repetitive transcranial magnetic stimulation (rTMS) reduces motor cortex excitability, but it is unclear whether this has behavioural consequences in healthy subjects. METHODS We examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 80% of active motor threshold) over left motor or left premotor cortex on performance in a visually cued choice reaction time task, using a 'masked prime' paradigm to assess whether rTMS might affect more automatic motor processes. Twelve healthy volunteers participated. RESULTS Motor cortex rTMS and, to a lesser extent, premotor cortex rTMS resulted in a slowing of right (stimulated) hand responses, but not of left (unstimulated) hand responses. In a control experiment, rTMS of the left somatosensory cortex did not lead to slower right hand responses. DISCUSSION We conclude that long trains of low intensity 1 Hz rTMS over the motor or premotor cortex can have subtle behavioural consequences outlasting the stimulation. rTMS did not affect the modulation of reaction times by subliminal primes, suggesting that priming effects triggered by subliminal primes are not generated at the level of motor or pre-motor cortex.
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Münchau A, Bloem BR, Thilo KV, Trimble MR, Rothwell JC, Robertson MM. Repetitive transcranial magnetic stimulation for Tourette syndrome. Neurology 2002; 59:1789-91. [PMID: 12473773 DOI: 10.1212/01.wnl.0000036615.25044.50] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In a single-blinded, placebo-controlled, crossover repetitive transcranial magnetic stimulation (rTMS) trial, 16 patients with Gilles de la Tourette syndrome (GTS) received in random sequence 1 Hz motor, premotor, and sham rTMS, which each consisted of two 20-minute rTMS sessions applied on 2 consecutive days. In the 12 patients who completed the trial, there was no significant improvement of symptoms after any of the rTMS conditions as assessed with the Motor tic, Obsessions and compulsions, Vocal tic Evaluation Survey.
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Allum JHJ, Carpenter MG, Honegger F, Adkin AL, Bloem BR. Age-dependent variations in the directional sensitivity of balance corrections and compensatory arm movements in man. J Physiol 2002; 542:643-63. [PMID: 12122159 PMCID: PMC2290411 DOI: 10.1113/jphysiol.2001.015644] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We investigated the effects of ageing on balance corrections induced by sudden stance perturbations in different directions. Effects were examined in biomechanical and electromyographic (EMG) recordings from a total of 36 healthy subjects divided equally into three age groups (20-34, 35-55 and 60-75 years old). Perturbations consisted of six combinations of support-surface roll (laterally) and pitch (forward-backward) each with 7.5 deg amplitude (2 pure pitch, and 4 roll and pitch) delivered randomly. To reduce stimulus predictability further and to investigate scaling effects, perturbations were at either 30 or 60 deg s(-1). In the legs, trunk and arms we observed age-related changes in balance corrections. The changes that appeared in the lower leg responses included smaller stretch reflexes in soleus and larger reflexes in tibialis anterior of the elderly compared with the young. For all perturbation directions, onsets of balance correcting responses in these ankle muscles were delayed by 20-30 ms and initially had smaller amplitudes (between 120-220 ms) in the elderly. This reduced early activity was compensated by increased lower leg activity after 240 ms. These EMG changes were paralleled by comparable differences in ankle torque responses, which were initially (after 160 ms) smaller in the elderly, but subsequently greater (after 280 ms). Findings in the middle-aged group were generally intermediate between the young and the elderly groups. Comparable results were obtained for the two different stimulus velocities. Stimulus-induced trunk roll, but not trunk pitch, changed dramatically with increasing age. Young subjects responded with early large roll movements of the trunk in the opposite direction to platform roll. A similarly directed but reduced amplitude of trunk roll was observed in the middle-aged. The elderly had very little initial roll modulation and also had smaller stretch reflexes in paraspinals. Balance-correcting responses (over 120-220 ms) in gluteus medius and paraspinals were equally well tuned to roll in the elderly, as in the young, but were reduced in amplitude. Onset latencies were delayed with age in gluteus medius muscles. Following the onset of trunk and hip balance corrections, trunk roll was in the same direction as support-surface motion for all age groups and resulted in overall trunk roll towards the fall side in the elderly, but not in the young. Protective arm movements also changed with age. Initial arm roll movements were largest in the young, smaller in the middle aged, and smallest in the elderly. Initial arm roll movements were in the same direction as initial trunk motion in the young and middle aged. Thus initial roll arm movements in the elderly were directed oppositely to those in the young. Initial pitch motion of the arms was similar across age groups. Subsequent arm movements were related to the amplitude of deltoid muscle responses which commenced at 100 ms in the young and 20-30 ms later in the elderly. These deltoid muscle responses preceded additional arm roll motion which left the arms directed 'downhill' (in the direction of the fall) in the elderly, but 'uphill' (to counterbalance motion of the pelvis) in the young. We conclude that increased trunk roll stiffness is a key biomechanical change with age. This interferes with early compensatory trunk movements and leads to trunk displacements in the direction of the impending fall. The reversal of protective arm movements in the elderly may reflect an adaptive strategy to cushion the fall. The uniform delay and amplitude reduction of balance-correcting responses across many segments (legs, hips and arms) suggests a neurally based alteration in processing times and response modulation with age. Interestingly, the elderly compensated for these 'early abnormalities' with enlarged later responses in the legs, but no similar adaptation was noted in the arms and trunk. These changes with age provide an insight into possible mechanisms underlying falls in the elderly.
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Horstink MWIM, Bloem BR. No male predominance in alpha-synuclein Parkinson's disease but the affected female fetus might be less viable. J Neurol Neurosurg Psychiatry 2002; 72:276-7. [PMID: 11796789 PMCID: PMC1737749 DOI: 10.1136/jnnp.72.2.276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Münchau A, Bloem BR, Irlbacher K, Trimble MR, Rothwell JC. Functional connectivity of human premotor and motor cortex explored with repetitive transcranial magnetic stimulation. J Neurosci 2002; 22:554-61. [PMID: 11784802 PMCID: PMC6758651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Connections between the premotor cortex and the primary motor cortex are dense and are important in the visual guidance of arm movements. We have shown previously that it is possible to engage these connections in humans and to measure the net amount of inhibition/facilitation from premotor to motor cortex using single-pulse transcranial magnetic stimulation (TMS). The aim of this study was to test whether premotor activation can affect the excitability of circuits within the primary motor cortex (M1) itself. Repetitive TMS (rTMS), which is known to produce effects that outlast the train at the site of stimulation, was given for 20 min at 1 Hz over premotor, primary motor, and sensory areas of cortex at an intensity of 80% of the active motor threshold for the motor hand area. The excitability of some corticocortical connections in M1 was probed by using paired-pulse testing of intracortical inhibition (ICI) and intracortical facilitation (ICF) with a coil placed over the motor cortex hand area. rTMS over the premotor cortex, but not other areas, changed the time course of the ICI/ICF for up to 1 hr afterward without affecting motor thresholds or motor-evoked potential recruitment. The cortical silent period was also shortened. The implication is that rTMS at a site distant from the motor cortex can change the excitability of circuits intrinsic to the motor cortex.
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Commissaris DACM, Nieuwenhuijzen PHJA, Overeem S, de Vos A, Duysens JEJ, Bloem BR. Dynamic posturography using a new movable multidirectional platform driven by gravity. J Neurosci Methods 2002; 113:73-84. [PMID: 11741724 DOI: 10.1016/s0165-0270(01)00477-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human upright balance control can be quantified using movable platforms driven by servo-controlled torque motors (dynamic posturography). We introduce a new movable platform driven by the force of gravity acting upon the platform and the subject standing on it. The platform consists of a 1 m2 metal plate, supported at each of its four corners by a cable and two magnets. Sudden release of the magnets on three sides of the platform (leaving one side attached) induces rotational perturbations in either the pitch or roll plane. Release of all magnets causes a purely vertical displacement. By varying the slack in the supporting cables, the platform can generate small (0.5 degrees ) to very destabilising (19 degrees ) rotations. Experiments in healthy subjects showed that the platform generated standardised and reproducible perturbations. The peak rotation velocity well exceeded the threshold required to elicit postural responses in the leg muscles. Onset latencies were comparable to those evoked by torque motor-driven platforms. Randomly mixed multidirectional perturbations of large amplitude forced the subject to use compensatory steps (easily possible on the large support surface), with little confounding influence of habituation. We conclude that this gravity-driven multidirectional platform provides a useful and versatile tool for dynamic posturography.
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Bloem BR, Allum JHJ, Carpenter MG, Verschuuren JJGM, Honegger F. Triggering of balance corrections and compensatory strategies in a patient with total leg proprioceptive loss. Exp Brain Res 2002; 142:91-107. [PMID: 11797087 DOI: 10.1007/s00221-001-0926-3] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2001] [Accepted: 09/21/2001] [Indexed: 11/26/2022]
Abstract
Triggering of balance corrections may depend on both leg and trunk proprioceptive inputs. To study this issue and to determine how a total proprioceptive loss in the legs (ToLPL) would affect postural reactions in different directions, we investigated the postural control of a patient with a long-standing dorsal root ganglionopathy. This patient had absent stretch reflexes at the ankle and knee joints, delayed reflexes at the hips, but normal muscle strength. Postural control was probed with support-surface movements driven by two different experimental protocols. The first protocol concentrated on leg muscle responses by varying ankle inputs during pitch plane perturbations. The second protocol focussed on the directional sensitivity of upper body responses using combined roll and pitch tilt perturbations. For both protocols, identical techniques were used to record ankle torques, angular velocities of the upper legs and trunk, and surface EMG from leg, hip and trunk muscles. For the first protocol, pitch plane stance perturbations with three different ankle inputs were imposed by a movable support surface. A simultaneous 4-cm rearward translation and 4-deg toe-up rotation produced an 80-deg/s "enhanced ankle input", a simple toe-up rotation gave a 40-deg/s "normal" ankle input and a simultaneous 4-cm rearward translation and 4-deg "toe-down" rotation yielding a 0-deg/s "nulled ankle input". Responses in the ToLPL patient were compared to those of healthy controls and those of patients with lower-leg proprioceptive loss (LLPL). Following normal and enhanced ankle input perturbations, stretch reflexes were absent in ankle and knee joint muscles of the ToLPL patient. Balance correcting responses in the lower legs were diminished and delayed by some 45 ms. In quadriceps, balance-correcting responses were larger than normal, peaked earlier and were not delayed. During the nulled ankle input condition, the ankle muscle responses in the ToLPL patient were again diminished and delayed by 40 ms with respect to both normal subjects and LLPL patients. However, the ToLPL patient again generated an earlier, larger, balance correcting response in quadriceps. For the second protocol, combinations of roll and pitch perturbations were also delivered by a moving support surface. The amplitude was 7.5 deg at 50 deg/s. Eight different directions were applied randomly (pure "toes down", pure "toes up" and directions at 45-deg intervals of roll). As with the first protocol pre-stimulus background muscle activity was excessive in all trunk and most leg muscles. Responses to roll tilt produced several striking changes from normal in the ToLPL patient. First reflexes in gluteus medius were delayed. Second, the trunk roll which commences around 30 ms in normals was in the opposite direction. This roll was accompanied by oppositely directed stretch reflexes in paraspinal muscles. Third, directional sensitivity of balance corrections was far more roll oriented in leg and trunk muscles. Fourth, some tilt directions caused a deactivation response of background activity. This "deactivation strategy" strongly contrasted with the strategy of controls who had low pre-stimulus background activity and activated responses around 100 ms to correct postural instability. These findings provide new insights into the generation of pitch and roll plane directed balance corrections based on the interaction of proprioceptive trigger signals from the ankles, knees and hips. Without proprioceptive input from the ankle and knee, ankle muscle responses are delayed but not absent. Upper leg and trunk responses are not delayed. This suggests that most, if not all, lower leg balance correcting responses are triggered by hip and, possibly, trunk proprioceptive inputs. When leg proprioceptive input is absent, balance correcting responses lose pitch plane sensitivity. The solution used by the patient to overcome these deficits was to markedly raise background muscle activity levels, presumably to provide a stiffer body structure. The lack of trunk flexibility and lateral instability this produced for roll tilts was offset by the ability to compensate by using a hitherto not described "deactivation response" strategy. The patient had a clinical picture usually described as "deafferented"; yet our roll tilt perturbations revealed delayed reflex responses in hip muscles. With vestibulospinal and neck-proprioceptive inputs, these responses may have helped with the development of compensation processes for the total leg proprioceptive deficit.
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Abstract
Simultaneous challenge of posture and cognition ("dual tasks") may predict falls better than tests of isolated components of postural control. We describe a new balance test (the Multiple Tasks Test, MTT) which (1) is based upon simultaneous assessment of multiple (>2) postural components; (2) represents everyday situations; and (3) can be applied by clinicians. Relevant risk factors for falls and actual fall circumstances (identified from a prospective survey in Parkinson's disease) were used to design functional tests (or postural "components") that resembled everyday situations. We distinguished a "cognitive" component (answering serial questions) from largely "motor" components (standing up, sitting down, turning around, walking, avoiding obstacles, and touching the floor). Four additional components included carrying an empty or loaded tray, wearing shoes with slippery soles and reduced illumination. These components were combined to yield eight separate tasks of increasing complexity that were executed sequentially. The first and simplest task consisted of standing up, undisturbed walking, turning around and sitting down. For each of the next tasks, a new component was added to the earlier and otherwise identical task. All components within each task had to be performed simultaneously. Errors were defined as Hesitations (slowed performance) or Blocks (complete cessation), which were scored separately for execution of motor and cognitive components. Speed of performance was not stressed, but was measured for all tasks. The MTT was administered to 50 young healthy subjects (mean age 27.6 years) and 13 elderly subjects (mean age 62.0 years). To study learning effects, 20 different young subjects (mean age 21.0 years) received the MTT in order of gradually decreasing complexity. For subjects who received the MTT in order of increasing difficulty, 62% in both age groups performed all eight tasks without any Errors in the motor components. Among those making Errors, the proportion of subjects that made motor Errors increased significantly as the tasks became more complex (F(1,7)=2.66, P<0.05). This increase differed across the two groups (significant interaction of Group by Task; F(1,7)=3.07, P=0.01) because more elderly subjects produced motor Errors during the most complex tasks. Cognitive Errors increased even more than motor Errors with task complexity, and this increase was most pronounced in young subjects (significant interaction of Group by Error Type by Task; F(1,1,7)=3.85, P=0.001). Only eight young (16%) and four elderly subjects (30.8%) performed the MTT without any motor or cognitive Errors, again suggesting that more young subjects made cognitive Errors. Among subjects who received the MTT in reverse order, motor errors were more common than among subjects who received the MTT in order of increasing complexity (F(1,7)=5.90, P<0.05), particularly during the two most difficult tasks. The elderly performed all tasks slower than the young subjects. We conclude that the MTT is a new balance test based upon a multiple task design that resembles everyday situations. Performance by healthy subjects revealed interesting insights into normal postural strategies. For complex postural tasks, healthy subjects favour execution of motor components over execution of a cognitive component ("posture first" strategy). Young subjects were more inclined than elderly subjects to use this strategy. Motor learning influenced performance among subjects who received the MTT in order of increasing difficulty. Further studies must determine whether the MTT can be used to evaluate balance disorders.
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Allum JH, Bloem BR, Carpenter MG, Honegger F. Differential diagnosis of proprioceptive and vestibular deficits using dynamic support-surface posturography. Gait Posture 2001; 14:217-26. [PMID: 11600325 DOI: 10.1016/s0966-6362(01)00142-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The objective of this study was to evaluate how effective dynamic support-surface posturography could be as a diagnostic tool in patients with balance disorders (proprioceptive or vestibular deficits). Specifically, we studied whether measures of trunk control and simple toe-up rotational perturbations, selected using statistical techniques, could provide a better diagnostic yield than either the analysis of lower-body movements or use of a "nulled" ankle input paradigm. The test subjects were 15 control subjects, five patients with bilateral peripheral vestibular loss (VL) and five patients with selective bilateral, lower-leg proprioceptive loss (PL). Amplitudes and onset latencies of bursts of EMG activity in upper and lower-leg muscles, paraspinals and trapezius muscles, concurrent changes in ankle torque, and peak amplitudes of upper-leg, lower-leg, and trunk angular-velocities were measured. Stimuli included three different types of sudden movements of the support surface, a "nulled" ankle input paradigm, a simple toe-up rotation paradigm, and a combined toe-up rotation and backwards translation of the support surface. All stimuli were tested under eyes-open and eyes-closed conditions. For each type of movement and condition the diagnostic classification accuracy (i.e. the overall sensitivity and specificity) was calculated based on those posturography measures providing the highest diagnostic separation between the three populations. Both patient groups showed increased trunk sway, changed support-surface reaction forces and muscle amplitudes compared with controls for toe-up and "nulled" test conditions. Measures providing the greatest diagnostic utility were the amplitude of trunk-angular velocity (increased in VL subjects, less so in PL), the amplitude of balance-correcting paraspinal responses (increased in VL subjects, decreased in PL subjects), the amplitude of trapezius stabilising responses (increased in both patient groups) for simple toe-up rotations under eyes-closed conditions. We conclude, that diagnosis of balance disorders using dynamic posturography is best achieved using measures of trunk control following pure toe-up rotational perturbations tested under eyes-closed conditions.
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Bloem BR, Grimbergen YA, Cramer M, Willemsen M, Zwinderman AH. Prospective assessment of falls in Parkinson's disease. J Neurol 2001; 248:950-8. [PMID: 11757958 DOI: 10.1007/s004150170047] [Citation(s) in RCA: 538] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We studied prospectively the epidemiology, clinical impact and prediction of falls in 59 moderately affected patients with Parkinson's disease (PD) (mean UPDRS motor score 31.5; mean age 61 years) and 55 controls (mean age 60 years). At baseline, balance and gait were evaluated extensively. The retropulsion test (response to sudden shoulder pull) was executed first unexpectedly and five more times following prior warning. All persons used standardised scoring forms to document their falls during six months. Thirty patients (50.8 %) and eight controls (14.5%) fell at least once (relative risk [RR] 6.1; 95% confidence interval [CI] 2.5-15.1, p < 0.001). Recurrent (> or = 2) falls occurred in 15 patients (25.4%), but in only two controls (RR 9.0; 95 % CI 2.0-41.7; p=0.001). Recurrent falls were more common among persons taking benzodiazepines (RR 5.0; 95% CI 1.6-15.5; p < 0.01). Sixty-two percent of the falls in patients caused soft tissue injuries, but no fractures occurred. A fear of future falls was common (45.8 % of patients) and was accompanied by restriction of daily activities (44.1 % of patients). Seventy percent of falls reported by patients were'intrinsic' (due to patient-related factors), but falls in controls were mainly (50%) 'extrinsic' (due to environmental factors). None of the baseline posture and gait variables predicted falls adequately. The first 'unexpected' retropulsion test was more often abnormal than all subsequent (predictable) tests. Irrespective of its method of execution, the retropulsion test did not predict falls. A combination of asking for prior falls, disease severity and the Romberg test yielded the best overall diagnostic utility (sensitivity 65 % and specificity 98 %). Recurrent fallers were best predicted by disease severity (RR for Hoehn and Yahr stage 3 was > 100; 95% CI 3.1-585) and asking for prior falls (RR 5.0; 95% CI 1.2-20.9). We conclude that falls are common and disabling, even in relatively early stage PD. Recurrent fallers were best predicted by disease severity and presence of prior falls. Strategies to prevent falls in PD should particularly focus at intrinsic (patient-related) factors, such as minimising the use of benzodiazepines.
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Gerschlager W, Bloem BR, Alesch F, Lang W, Deecke L, Cunnington R. Bilateral subthalamic nucleus stimulation does not improve prolonged P300 latencies in Parkinson's disease. J Neurol 2001; 248:285-9. [PMID: 11374092 DOI: 10.1007/s004150170202] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Bilateral deep brain stimulation is an effective treatment for most motor signs of Parkinson's disease (PD), but the effects on cognitive functions are less clear. We therefore examined the effects of bilateral deep brain stimulation on central information processing, using the event-related auditory P300 potential as an electrophysiological index of mental chronometry. Eight PD patients with bilateral stimulators within the subthalamic nuclei (STN) and eight age-matched controls participated. Patients were examined after overnight withdrawal of antiparkinson medication, both "on" and "off" stimulation (in random sequence). The P300 and reaction times were recorded using an auditory oddball paradigm. P300 latencies were prolonged in PD patients off stimulation (440 +/- 45 ms) compared to controls (397 +/- 16 ms; P < 0.05). STN stimulation significantly reduced clinical disease severity (as indexed by the Unified Parkinson's Disease Rating Scale) and markedly improved reaction times, but did not improve the prolonged P300 latencies in PD patients (429 +/- 36 ms). These results confirm that P300 latencies are prolonged in PD. Significantly, bilateral STN stimulation did not improve this electrophysiological measure of cognitive impairment, even though motor disability was markedly reduced. This suggests that some dopa-responsive features are resistant to STN stimulation, possibly due to involvement of dopaminergic deficits outside the nigrostriatal pathway, which are not influenced by outflow from the STN.
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Roofthooft DWE, Bloem BR, Brouwer OF, Lammers GJ, Beaufort AJ. Neonatale myoclonieën na maternaal clomipramine-gebruik tijdens de zwangerschap. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf03061336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Boers I, Gerschlager W, Stalenhoef PA, Bloem BR. Falls in the elderly. II. Strategies for prevention. Wien Klin Wochenschr 2001; 113:398-407. [PMID: 11467085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In the companion paper, we have outlined how relevant risk factors for falls can be identified using a systematic approach. Once identified, the underlying diseases and pattern of (usually multiple) risk factors guides the design of an individually tailored intervention program. Such intervention programs follow one or more of the following goals: (a) to treat the underlying disease; (b) to reduce or even eliminate the number of falls; (c) to prevent or minimise the associated injuries; and (d) tertiary prevention of fall-related disability, including immobilisation, muscle weakness, reduced fitness, osteoporosis, fear of falling and mortality. The successful results of various intervention studies underscores that falls should be regarded as a potentially treatable disorder in elderly persons. Such knowledge is important for clinicians, which could apply prevention strategies to individual patients with risk factors that are strongly associated with falls. In addition, prevention is important for health policy makers who aim to reduce falls in the general population by reducing or eliminating commonly present risk factors (even if they are only weakly associated with falls).
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Bloem BR, Boers I, Cramer M, Westendorp RG, Gerschlager W. Falls in the elderly. I. Identification of risk factors. Wien Klin Wochenschr 2001; 113:352-62. [PMID: 11432124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Falls severely threaten the health of elderly persons and pose high costs to the public health service. Unfortunately, falls are often regarded as unavoidable and untreatable features of aging. Therefore, many clinicians merely treat the physical injuries of a fall. However, falls and gait limitations are markers of underlying (sometimes otherwise subclinical) diseases that can be amenable to treatment. Moreover, falls and gait limitations herald the onset of repeated falls, physical decline, serious psychosocial consequences and a reduced survival. We review how clinically relevant risk factors can be traced by reviewing the medical notes, by careful history taking and by physical examination. The identified risk factors can serve as a template for the design of prevention strategies, which are discussed in the companion article.
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Bloem BR, Valkenburg VV, Slabbekoorn M, van Dijk JG. The Multiple Tasks Test. Strategies in Parkinson's disease. Exp Brain Res 2001; 137:478-86. [PMID: 11355392 DOI: 10.1007/s002210000672] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The clinical balance tests presently used cannot predict falls in Parkinson's disease (PD), perhaps because they probe fairly isolated "components" of postural control. The Multiple Tasks Test (MTT) is a new balance test that simultaneously assesses multiple components of postural control. We investigated whether this MTT can detect postural abnormalities in PD patients. Fifty young controls (mean age 27.6 years), 20 elderly controls (mean age 62.5 years), and 20 PD patients (mean age 61.8 years, mean Hoehn and Yahr stage 2.2) participated. The MTT consisted of eight separate tasks of increasing complexity, which were executed sequentially. These tasks were composed of several motor components (standing up, walking, avoiding obstacles, touching the floor, turning around, and sitting down) and one cognitive component (answering serial questions). Four additional components included carrying an empty or loaded tray, wearing slippery shoes, and reduced illumination. All components within each task had to be performed simultaneously or directly sequentially. Errors were defined as Hesitations (slowed performance) or Blocks (complete cessation), which were scored separately for execution of the motor and cognitive components. Speed of performance was not stressed, but we did measure the time taken to complete all tasks. The complete MTT was performed by all subjects, except for a subgroup of seven patients and seven elderly controls who performed a shortened version, with only three of the eight sequential tasks (simple, intermediate, and most difficult). The number of subjects that produced Hesitations or Blocks for the motor components differed between the three groups [two-way repeated measures MANOVA, F(2.7) = 20.56; P < 0.001], patients making more errors than young and elderly controls. Furthermore, the number of subjects that made motor errors increased as the tasks became more complex [F(2.7) = 6.69; P < 0.001]. This increase differed across the three groups [significant interaction effect; F(2.7) = 3.31; P < 0.001] because particularly patients produced motor errors during the more complex tasks. In both control groups, 62% performed all eight consecutive tasks without errors in the motor components. In contrast, only 8% of the patients completed all tasks without motor errors (log rank test, P < 0.0001). This difference between patients and controls disappeared if the cognitive component was also scored, because more controls made cognitive errors during complex tasks than patients. Controls apparently gave priority to execution of the motor components, which they performed significantly faster than the patients. Both patients and controls made more errors during the shortened MTT, suggesting that learning effects (gain in performance through practice) influenced performance on the complete test. The MTT is a new balance test that clearly discriminates between healthy subjects and PD patients. Unlike controls, PD patients lend less priority to motor tasks over cognitive tasks. In addition, impaired motor learning may partially explain the higher error rate in PD. Future studies must determine if impaired MTT performance can predict actual falls in daily life.
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Bloem BR, van Vugt JP, Beckley DJ. Postural instability and falls in Parkinson's disease. ADVANCES IN NEUROLOGY 2001; 87:209-23. [PMID: 11347224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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Willemsen MD, Grimbergen YA, Slabbekoorn M, Bloem BR. [Falling in Parkinson disease: more often due to postural instability than to environmental factors]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 2000; 144:2309-14. [PMID: 11143299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
OBJECTIVE To document the circumstances surrounding falls in patients with Parkinson's disease. DESIGN Prospective. METHOD Parkinson patients with a check-up appointment in the period 1 May 1998-31 May 1999 at the Neurology Outpatient's Department of Leiden University Hospital, used standardized forms to record the circumstances surrounding all incidents of falling during the subsequent 6 months. For control purposes, a partner or acquaintance with comparable living conditions was asked to do the same. The researchers judged whether falls were related to physical impairment (personal, intrinsic factors) or environmental factors (extrinsic factors). RESULTS 59 patients with Parkinson's disease (21 women (36%); mean age: 60.8 years; mean Hoehn and Yahr score: 2.3) and 55 controls (37 women (67%); mean age: 59.6 years) were studied. Patients reported 205 falls and controls 10 falls. Recurrent (> or = 2) falls occurred in 15 patients (25%) and two controls (4%) (relative risk (RR): 9.0: 95% confidence interval (95% CI): 2.0-41.7). Recurrent falls were more common among persons using benzodiazepines (RR: 5.0: 95% CI: 1.6-15.5). Reliable information was obtained for 160 falls in patients. Most falls (79%) had an intrinsic cause, like turning around, standing up, bending and stumbling. Abrupt movements were a particularly frequent cause of falls. Simultaneous performance of multiple tasks contributed to almost 50% of falls in patients. CONCLUSION Falls are common among Parkinson patients. Most falls are related to intrinsic factors. Prevention of these intrinsic falls requires treatment of the underlying postural instability. Use of benzodiazepines must be avoided whenever possible. Interventions aimed at extrinsic factors, such as reduction of domestic hazards, are possibly less effective.
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Bloem BR, Gussekloo J, Lagaay AM, Remarque EJ, Haan J, Westendorp RG. Idiopathic senile gait disorders are signs of subclinical disease. J Am Geriatr Soc 2000; 48:1098-101. [PMID: 10983910 DOI: 10.1111/j.1532-5415.2000.tb04786.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate survival and causes of death in subjects with idiopathic senile gait disorders. DESIGN A population-based longitudinal study. SETTING Survival analysis of the oldest old within the Leiden 85-plus Study. PARTICIPANTS We distinguished three different groups according to their gait: subjects with a normal gait (n = 25), subjects with senile gait disorders (n = 14), and subjects with gait disorders due to known disease (n = 87). The mean age was 90 years in all groups (range 87 to 97 years). MEASUREMENTS The risk of all cause mortality and cardiovascular mortality was estimated over 5 years of follow-up in a Cox-proportional hazards model, adjusted for age and sex. RESULTS Eighty-nine of 126 subjects died during follow-up. Mean survival differed among the three groups (P log-rank = .01). All cause mortality risk was increased in subjects with senile gait disorders compared with subjects with a normal gait (RR = 2.8; 95% CI, 1.1-7.3, P = .03) and was similar to subjects with gait disorders caused by known disease (RR = 1.2; 95% CI: .6-2.5, P = .6). Mortality caused by cardiovascular disease also differed among the three groups (P log-rank = .03). The risk of cardiovascular death in subjects with senile gait disorders was twofold greater than in subjects with a normal gait (RR = 2.1; 95% CI, 0.4-10.3). CONCLUSIONS Senile gait disorders are related to subclinical, perhaps cardiovascular, disease. Senile gait disorders should not be accepted as an inevitable, benign concomitant of the normal aging process.
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Abstract
A diagnostic lumbar puncture was performed in a 12-year-old male with acute lymphoblastic leukemia. Because of thrombocytopenia (platelet count 42,000/mm(3)), a platelet transfusion was given immediately before the lumbar puncture. However, the platelet count was not re-examined. The patient developed progressive paraparesis shortly after the lumbar puncture. Magnetic resonance imaging revealed an extensive spinal subdural hematoma from the T2 to S2 level. This case report illustrates the sometimes dramatic consequences of lumbar puncture in patients with childhood leukemia. Guidelines for the examination of the platelet count and correction of thrombocytopenia before lumbar puncture are discussed.
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Bloem BR, Allum JH, Carpenter MG, Honegger F. Is lower leg proprioception essential for triggering human automatic postural responses? Exp Brain Res 2000; 130:375-91. [PMID: 10706436 DOI: 10.1007/s002219900259] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It is unknown to what extent automatic postural responses are triggered by lower leg proprioception. This issue was addressed by studying postural control in five carefully selected patients with subtle diabetic polyneuropathy (restricted to the lower legs) and 15 healthy subjects. All patients had bilaterally absent Achilles tendon reflexes and weak or absent patella tendon reflexes, but muscle strength was fully preserved. Subjects were tested while standing on a supporting, movable force-plate. The contribution of lower leg proprioception to automatic postural responses was investigated by randomly exposing the subjects to either a 4 degrees 'toe-up' rotational perturbation ('normal ankle input'), a simultaneous 4-cm rearward translation and 4 degrees toe-up rotation ('enhanced ankle input'), or a simultaneous 4-cm rearward translation and 4 degrees 'toe-down' rotation ('nulled ankle input'). We recorded surface EMG (stretch reflexes and balance-correcting responses) from leg and trunk muscles, ankle torque and angular velocities of the upper and lower legs and trunk. We argued that automatic postural responses that have abnormally small amplitudes in patients and are modulated in controls with the velocity of different types of ankle rotations must receive a major input from lower leg proprioception. Conversely, automatic postural responses that are weakly modified in amplitude or onset by different ankle perturbations and are present despite nulled ankle inputs and, finally, are unaffected in patients with distal polyneuropathy must be triggered or modulated by inputs other than from lower leg proprioception. Normal postural synergies and strategies were maintained in patients, although within a given synergy the timing and amplitude of some automatic postural responses were abnormal. A few automatic postural responses appeared to be triggered or modulated by lower leg proprioception. Thus, early stretch reflexes in soleus and medial gastrocnemius were severely diminished in patients, while in controls these stretch reflexes were modulated by different ankle perturbations. Furthermore, balance-correcting responses in tibialis anterior were diminished and delayed in patients, while in controls these balance-correcting responses were modulated by different ankle perturbations. Other automatic postural responses were apparently not triggered or modulated by lower leg proprioception, but likely received a major input from more proximal sensory systems. Thus, in both groups prominent balance-correcting responses were present in several muscles (soleus, gastrocnemius, quadriceps, paraspinals and trapezius) during the 'nulled ankle input' condition, where ankle position was stabilised over the first 250 ms. During the 'enhanced ankle input' condition, where prominent ankle dorsiflexion occurred during the first 200 ms, amplitudes of balance-correcting responses were only marginally weaker in patients than in controls. We analysed body segment displacements to unveil the potential nature of proximal triggers for automatic postural responses. As opposed to the 'inverted pendulum' concept of postural control, early movement occurred in the knees, hips and trunk well before the onset of automatic postural responses. For example, during the 'nulled ankle input' condition, the lower leg moved forward with early knee flexion, followed by knee extension. The trunk extended backwards at 80 ms, which was followed by forward flexion. The absent stretch reflex and weaker balance-correcting responses in patients produced changed trunk velocity profiles (mainly a reduced initial backward motion of the trunk), but lower-body segment movements showed no consistent differences between the two groups. Considering these body segment displacements, any automatic postural response with an onset within the first 200 ms could well be triggered by receptors located at the knee, hip or trunk. (ABSTRACT TRUNCATED)
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van Putten MJ, Bloem BR, Smit VT, Aarts NJ, Lammers GJ. An uncommon cause of stroke in young adults. ARCHIVES OF NEUROLOGY 1999; 56:1018-20. [PMID: 10448810 DOI: 10.1001/archneur.56.8.1018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We describe a previously healthy 48-year-old man who presented with clinical characteristics suggestive of internal carotid artery dissection, confirmed by magnetic resonance imaging. He developed a massive infarction of the left cerebral hemisphere and died after 3 days of transtentorial herniation. Post-mortem examination identified a dissection of the thoracic aorta caused by Erdheim-Gsell cystic medionecrosis, with the characteristic degeneration of the elastic fibers of the lamina media. The dissection showed an unusually large extension not only distally into both iliac arteries, but also proximally into both carotid arteries. To our knowledge, such an extensive dissection has not been described previously. Underlying vessel wall disorders of the aorta, such as Erdheim Gsell cystic medionecrosis, should be considered in young patients with spontaneous arterial dissection.
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Bloem BR, Lammers GJ, Roofthooft DW, De Beaufort AJ, Brouwer OF. Clomipramine withdrawal in newborns. Arch Dis Child Fetal Neonatal Ed 1999; 81:F77. [PMID: 10744432 PMCID: PMC1720967 DOI: 10.1136/fn.81.1.f77a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bloem BR, de Roos MA, de Beaufort AJ, Brouwer OF. [The stumbling toddler]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 1999; 143:1185-8. [PMID: 10389530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Four previously healthy children, two boys aged 5 and one boy and one girl aged 4 more or less acutely developed a stumbling gait. The causes varied from benign such as postviral acute cerebellar ataxia and benign paroxysmal vertigo to potentially life-threatening such as intoxication with benzodiazepines and medulloblastoma. Treatment led to complete or partial recovery. (Sub)acute balance disorders in previously healthy children can be due to cerebellar ataxia, vestibular disorders and abnormal proprioception. Ancillary investigations are warranted in case of gradually developing ataxia, accompanying neurological deficits, suspicion of intoxication, recurrent or familial ataxia, no spontaneous remission or even progression. In children with an isolated cerebellar ataxia without these features, ancillary investigations may be avoided, although in such cases careful follow-up remains necessary.
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Bloem BR, Beckley DJ, van Dijk JG. Are automatic postural responses in patients with Parkinson's disease abnormal due to their stooped posture? Exp Brain Res 1999; 124:481-8. [PMID: 10090660 DOI: 10.1007/s002210050644] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abnormal automatic postural responses are thought to contribute to balance impairment in Parkinson's disease. However, because postural responses are modifiable by stance, we have speculated that some postural abnormalities in patients with Parkinson's disease are secondary to their stooped stance. We have studied this assumption by assessing automatic postural responses in 30 healthy subjects who were instructed either to stand upright or to assume a typical parkinsonian posture. During both conditions, subjects received 20 serial 4 degrees 'toe-up' rotational perturbations from a supporting forceplate. We recorded short-latency (SL) and medium-latency (ML) responses from stretched gastrocnemius muscles and long-latency (LL) responses from shortened tibialis anterior muscles. We also assessed changes in the center of foot pressure (CFP) and the center of gravity (COG). The results were qualitatively compared to a previously described group of patients with Parkinson's disease who, under these circumstances, typically have large ML responses, small LL responses and insufficient voluntary postural corrections, accompanied by a slow rate of backward CFP displacement and an increased posterior COG displacement. The stooped posture resulted in unloading of medial gastrocnemius muscles and loading of tibialis anterior muscles. Onset latencies of stretch responses in gastrocnemius muscles were delayed in stooped subjects, but the onset of LL responses was markedly reduced. Amplitudes of both ML and LL responses were reduced in stooped subjects. Prestimulus COG and, to a lesser extent, CFP were shifted forwards in stooped subjects. Posterior COG displacement and the rate of backward CFP displacement were diminished in stooped subjects. Voluntary postural corrections were unchanged while standing stooped. These results indicate that some postural abnormalities of patients with Parkinson's disease (most notably the reduced LL responses) can be reproduced in healthy subjects mimicking a stooped parkinsonian posture. Other postural abnormalities (most notably the increased ML responses and insufficient voluntary responses) did not appear in stooped controls and may contribute to balance impairment in Parkinson's disease.
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Bloem BR, Grimbergen YA, Roos RA. [Don't let the patient with Parkinson's disease fall!]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 1998; 142:2825-7. [PMID: 10065254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Three patients with a hypokinetic-rigid syndrome, a woman aged 69 years and two men aged 62 and 67 years, were admitted because of frequent falling. In two patients Parkinson's disease was diagnosed, the third had progressive supranuclear palsy. Balance impairment and falls typically emerge late in the course of Parkinson's disease. Falls can have dramatic physical consequences, such as (hip) fractures, and often induce a fear of additional falls which further impairs mobility and social contacts. The pathophysiology of falls in Parkinson's disease is complex and appears to result from both impaired balance regulation and commonly occurring balance disturbances (due to the shuffling gait and dyskinesias). Balance impairment often responds insufficiently to pharmacological treatment. Aspecific measures such as physical therapy, walking aids and reduction of domestic hazards can reduce the number of falls. Because patients often fail to voluntarily report their falls, physicians must actively pay attention to balance impairment in Parkinson's disease.
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Bloem BR, Beckley DJ, van Hilten BJ, Roos RA. Clinimetrics of postural instability in Parkinson's disease. J Neurol 1998; 245:669-73. [PMID: 9776467 DOI: 10.1007/s004150050265] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Judgement of the ability to recover balance after a sudden shoulder pull is used as a clinical measure of postural instability in Parkinson's disease. To further evaluate its merits, we compared this 'retropulsion test' with dynamic posturography in 23 Parkinson patients. Dynamic posturography involved 20 serial 'toe-up' support surface rotations, which induced backward body sway. We found a moderate correlation (Spearman's p = 0.54; P < 0.05) between the retropulsion test and body sway after platform rotations during the 'off' phase, but no correlation during the 'on' phase (Spearman's p = 0.43; P = 0.11). These results cast doubt on the use of the retropulsion test as a measure of postural instability in Parkinson's disease.
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Beckley DJ, Bloem BR, Martin EM, Panzer VP, Remler MP. Postural reflexes in patients with HIV-1 infection. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 109:402-8. [PMID: 9851297 DOI: 10.1016/s0924-980x(98)00040-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE We studied whether medium latency (ML) and long latency (LL) postural reflexes, which are abnormal in a number of neurological conditions including basal ganglia disorders, provide an early marker of CNS involvement in HIV-positive patients. METHODS Leg reflexes were elicited in 9 neurologically normal HIV-positive patients and 10 healthy controls who were standing upright, using toe-up forceplate rotations of varying amplitude (4 degrees and 10 degrees) and predictability (serial and random). RESULTS For predictable amplitude perturbations, posturally destabilizing ML and stabilizing LL responses in HIV-seropositives did not differ from controls. However, for unpredictable amplitude perturbations, HIV-positive patients inappropriately manifested a mid-size default LL response, in contrast to healthy subjects who showed a maximum size default response. CONCLUSIONS These results suggest that impaired modulation of LL reflex processing occurs in early stages of HIV infection, prior to the onset of clinical postural instability, and this dysregulation may be influenced by cognitive factors.
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Arnoldus EP, Bloem BR, van Dijk JG, Lammers GJ. Prolonged coma and severely attenuated EEG after a single seizure. Epilepsia 1998; 39:669-70. [PMID: 9637611 DOI: 10.1111/j.1528-1157.1998.tb01437.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A 63-year-old woman presented with a comatose state after a fall. Results of cranial computed tomography (CT) and magnetic resonance imaging (MRI) scans were normal. An EEG recorded 5 h after admission was very severely attenuated and slowed. Consciousness and EEG were improved the next day. No cause was detected initially. After sleep deprivation, the patient had a generalized seizure followed by a similar coma and EEG. Even a single seizure may cause a prolonged coma with a very severely attenuated and slowed EEG.
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Bloem BR, van Vugt JP, Beckley DJ, Remler MP, Roos RA. Habituation of lower leg stretch responses in Parkinson's disease. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 109:73-7. [PMID: 11003067 DOI: 10.1016/s0924-980x(97)00073-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In young healthy subjects, initially large stretch responses in leg muscles are progressively attenuated following a series of identical postural perturbations. We have studied whether this habituation of stretch responses is impaired in Parkinson's disease. Ten patients and 10 elderly controls received 10 serial 'toe-up' rotational perturbations (amplitude 10 degrees) while standing on a supporting forceplate. We recorded posturally destabilizing medium latency (ML) stretch responses from the medial gastrocnemius muscle. Functional habituation across the first few trials occurred in patients, but not in elderly controls. The rate of habituation was influenced by the size of the response to the first perturbation. This observation explained the absence of habituation in elderly subjects because their responses during the first few trials were much smaller compared to patients. These results suggest that habituation of lower leg stretch responses is unimpaired in Parkinson's disease. The presence of initially large and 'unpracticed' responses may partially explain why Parkinson patients fall in response to unexpected postural disturbances that commonly occur in daily life.
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Bloem BR, van Putten MJ, van der Meer FJ, van Hilten JJ, Bertina RM. Superior sagittal sinus thrombosis in a patient heterozygous for the novel 20210 A allele of the prothrombin gene. Thromb Haemost 1998; 79:235. [PMID: 9459354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Bloem BR, Ferwerda SK, Gerritsen JJ, Lammers GJ. [Hypertension in the acute phase of brain infarct; generally do not treat]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 1997; 141:1583-4. [PMID: 9543760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bloem BR, Boers I, Lagaay AM, Haan J, Wintzen AR, Roos RA. [Gait impairment in the oldest old]. Tijdschr Gerontol Geriatr 1997; 28:76-81. [PMID: 9221558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To evaluate senile gait patterns in octogenarians and nonagenarians, we provided a standardized questionnaire on gait disabilities to 153 elderly subjects over 88 years of age. Subjects represented a relatively healthy subgroup of non-institutionalized residents who participated in a gerontological survey of all inhabitants of the city of Leiden who were 85 years or older. Of the 142 subjects who responded to this questionnaire, 87 persons (61%) claimed distinct diseases as a cause of gait impairment. Of the remaining 55 persons, 42 received a standardized gait assessment. Gait was classified as completely normal in 25 persons (18% of all responders), whereas in three other persons gait could not reliably be classified as either normal or abnormal. A wide spectrum of clear gait abnormalities-mainly with ataxic features-was encountered in the remaining 14 persons (10%). It is concluded that some elderly subjects have a mainly ataxic gait disturbance which seems unrelated to the presence of distinct diseases. Although additional investigations might still reveal underlying pathology in these subjects, their gait impairment may represent the "idiopathic senile gait disorder'. In addition, a relatively high number of very old community residents have a completely normal gait.
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Bloem BR, Roon KI, Delleman NJ, van Dijk JG, Roos RA. Prolonged duration of standing up is an early dopa-sensitive abnormality in Parkinson's disease. J Neurol Sci 1997; 146:41-4. [PMID: 9077494 DOI: 10.1016/s0022-510x(96)00274-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We studied the influence of dopaminergic medication on the duration of standing up, static posture and gait in five patients with Parkinson's disease (Hoehn and Yahr stage 1.5 to 3) and four healthy controls, using an optoelectronic camera system. Duration of standing up was prolonged in patients, while static posture and gait were largely unaffected. The prolonged duration of standing up was corrected by dopaminergic medication. These results suggest that an increased duration of standing up is a relatively early and dopa-sensitive abnormality in Parkinson's disease.
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Bloem BR, Beckley DJ, van Dijk JG, Zwinderman AH, Remler MP, Roos RA. Influence of dopaminergic medication on automatic postural responses and balance impairment in Parkinson's disease. Mov Disord 1996; 11:509-21. [PMID: 8866492 DOI: 10.1002/mds.870110506] [Citation(s) in RCA: 157] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
It is still unclear why balance impairment in Parkinson's disease (PD) often responds insufficiently to dopaminergic medication. We have studied this issue in 23 patients with idiopathic PD and 24 healthy controls. Our specific purposes were (a) to investigate the contribution of abnormal automatic postural responses to balance impairment in PD and (b) to assess the influence of dopaminergic medication on abnormal automatic postural responses and balance impairment. Standing subjects received 4 degrees "toe-up" rotational perturbations of a supporting forceplate. We bilaterally recorded posturally destabilizing medium latency (ML) responses from the stretched gastrocnemius muscles and functionally corrective long latency (LL) responses from the shortened tibialis anterior (TA) muscles. We also assessed changes in the center of foot pressure (CFP) and the center of gravity (COG). All patients were tested in the "off" and "on" phases. All controls were tested and retested after 1 h. During the off phase, we found enlarged ML amplitudes and diminished LL amplitudes in patients, together with a markedly increased posterior displacement of the COG. The abnormal ML and LL responses were partially responsible for the increased body sway in patients because the initial forward (destabilizing) displacement of the CFP was increased, while the subsequent backward displacement of the CFP (a measure of the corrective braking action of LL responses) was delayed. Abnormal late automatic or possibly more voluntary postural corrections also contributed substantially to the increased body sway. During the on phase, ML amplitudes were reduced in patients but remained increased compared with controls. LL amplitudes no longer differed between both groups due to a modest, possibly dopamine-related increase in patients and a simultaneous decrease in controls. The abnormal CFP displacement was only partially improved by dopaminergic medication. The later postural corrections were not improved at all. Consequently, the increased posterior COG displacement was not ameliorated during the on phase. We conclude that (a) a combination of abnormal automatic and perhaps more voluntary postural corrections contributes to increased body sway in PD and (b) dopaminergic medication fails to improve balance impairment in PD because early automatic postural responses are only partially corrected, while later occurring postural corrections are not improved at all. These electrophysiological results support clinical observations and suggest that nondopaminergic lesions play a significant role in the pathophysiology of postural abnormalities in PD.
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van Hilten JJ, Bloem BR, Klaassen AA. Deprenyl's neuroprotective action remains unresolved. Ann Neurol 1996; 40:266-7. [PMID: 8773615 DOI: 10.1002/ana.410400226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Beckley DJ, Panzer VP, Remler MP, Ilog LB, Bloem BR. Clinical correlates of motor performance during paced postural tasks in Parkinson's disease. J Neurol Sci 1995; 132:133-8. [PMID: 8543938 DOI: 10.1016/0022-510x(95)00130-t] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bradykinesia and hypokinesia may both play a significant role in postural instability commonly seen in patients with Parkinson's disease. We investigated which factor--movement time or movement amplitude--is the more significant limiting variable in patients with Parkinson's disease during a paced postural task. We also assessed the effect of antiparkinson medication upon these movement factors and the degree of correlation with changes in clinical performance. Subjects performed paced left-right (L-R) and forward-backward (F-B) continuous weight-shifting tasks at slow, medium and fast paces. Ten Parkinson patients were studied both OFF and ON their usual antiparkinson medication. Ten age-matched healthy controls were also tested and subsequently retested on the same schedule as the patients. Movement times and amplitudes were measured and correlated with clinical changes in UPDRS motor subscores. Parkinson patients performed similar to controls with respect to movement time, but significantly displayed underscaled (reduced) movement amplitude. Movement amplitude improved after antiparkinson medication, but remained significantly less than that of controls. Improvements in L-R movement amplitude correlated with clinical improvements in bradykinesia and postural instability, while improved F-B movement amplitude correlated only with reduced postural instability. We conclude that hypometric movement amplitude, and not abnormal movement time, is the primary abnormality observed in Parkinson patients during a paced postural task. Amplitude underscaling seems antiparkinson medication-dependent and improvement correlates with favorable clinical changes in bradykinesia and postural instability scores.
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Bloem BR, Beckley DJ, van Vugt JP, van Dijk JG, Remler MP, Langston JW, Roos RA. Long latency postural reflexes are under supraspinal dopaminergic control. Mov Disord 1995; 10:580-8. [PMID: 8552109 DOI: 10.1002/mds.870100509] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Scaling of posturally stabilizing long latency (LL) reflexes in tibialis anterior muscles induced by "toe-up" rotational perturbations is abnormal in standing patients with Parkinson's disease. To investigate the contribution of dopaminergic pathways to abnormal scaling, we studied LL reflexes in 22 patients with selective hypodopaminergic syndromes: 10 psychiatric patients taking chronic neuroleptic medication (7 with mild parkinsonism), 8 patients with young-onset Parkinson's disease, and 4 patients with MPTP-induced parkinsonism. Results were compared with those of 10 healthy controls. Stimuli consisted of (a) 10 serial (predictable) perturbations of 4 degrees amplitude, (b) 10 serial (predictable) perturbations of 10 degrees amplitude, and (c) 20 randomly mixed (unpredictable) perturbations of either 4 or 10 degrees amplitude. In normal subjects, LL reflex amplitudes were adapted to match predictable variations in stimulus size, whereas under unpredictable conditions a "default" response emerged that anticipated the 10 degrees perturbation. LL reflex scaling under predictable conditions was intact in patients with neuroleptic-induced parkinsonism and young-onset Parkinson's disease, but the large default LL response under unpredictable conditions was absent. In patients with MPTP-induced parkinsonism, LL reflex scaling was absent during both predictable and unpredictable conditions. We conclude that abnormal scaling of posturally stabilizing LL reflexes is related to decreased supraspinal dopaminergic influence.
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Bloem BR, van Dijk JG, Roos RA. [With maintaining equilibrium: experimental study of the limits of acceleration which the human body can endure without losing postural balance]. NEDERLANDS TIJDSCHRIFT VOOR GENEESKUNDE 1995; 139:905. [PMID: 7646660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Bloem BR, Beckley DJ, Remler MP, Roos RA, van Dijk JG. Postural reflexes in Parkinson's disease during 'resist' and 'yield' tasks. J Neurol Sci 1995; 129:109-19. [PMID: 7608724 DOI: 10.1016/0022-510x(94)00253-k] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Postural reflexes in leg muscles appear to be set at a fixed gain in Parkinson's disease. To further investigate gain adaptation, we instructed 16 patients with idiopathic Parkinson's disease (studied during the 'off' phase) and 21 healthy controls to either 'resist' or 'yield' in response to 20 serial 4 degrees toe-up perturbations of a supporting platform on which they were standing. We bilaterally recorded destabilizing medium latency (ML) reflexes from stretched gastrocnemius muscles and corrective long latency (LL) reflexes from shortened tibialis anterior muscles. We also assessed changes in center of foot pressure (CFP) and center of gravity (COG). During the 'resist' condition, patients had increased destabilizing ML reflexes, decreased corrective LL reflexes, increased backward displacement of the COG and increased forward (destabilizing) displacement of the CFP. In addition, the backward (corrective) displacement of CFP between 150 and 250 ms was delayed. During the 'yield' condition, reflex gains were modified in controls: LL reflexes were markedly attenuated, whereas ML reflexes were markedly increased. Although this reflex pattern resembled the 'resist' condition in patients, it was not associated with an increased forward displacement of the CFP, but only with a strongly delayed backward displacement of CFP which started after 150 ms. In patients, ML reflex amplitudes remained unchanged during the 'yield' condition, suggesting a fixed reflex gain. LL reflex amplitudes were reduced in patients but significantly less compared to controls, which again suggests a fixed reflex gain. This 'inflexibility' of postural reflexes was reflected by the CFP which showed much smaller changes between 0 and 250 ms in patients than controls. These results could not be ascribed to a different ability to yield because posterior displacement of the COG was identical in patients and controls during the 'yield' condition. We conclude that (1) patients with Parkinson's disease have abnormal and 'inflexible' postural reflexes, associated with delayed corrective movements about the ankle joint and increased body sway; and (2) the increased forward displacement of the CFP in patients likely reflects high stiffness in ankle muscles because reflex changes in controls only affected the CFP more than 150 ms after the perturbation. The increased muscle stiffness and inflexibility of postural reflexes in Parkinson's disease may contribute to balance impairment in daily life.
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Bloem BR, Beckley DJ, van Dijk JG, Remler MP, Roos RA. Stretch reflexes in Parkinson's disease. Acta Neurol Scand 1995; 91:76-8. [PMID: 7732781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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