The mechanism of bradykinesia in parkinsonism

Brumlik, Joel; Boshes, Benjamin

doi:10.1212/wnl.16.4.337

Cited by 36 publications

(14 citation statements)

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“…When healthy subjects are forced to make a visually guided movement before they are ready, the resulting movement is inaccurate, reflecting incomplete specification of the motor plan (Hening et al, 1988;Favilla et al, 1989). The increased motor preparation time that has been described in PD (Brumlik and Boshes, 1966;Evarts et al, 1981;Hallett, 1990), and confirmed in our study, could thus lead to a degradation of the motor plan, resulting in movement inaccuracy, when patients attempt to move as soon as possible rather than when ready. Allowing subjects in our study to make each movement only when ready allowed full, and thus more accurate, formulation of the motor plan before each movement.…”

Section: Discussionsupporting

confidence: 81%

Why Don't We Move Faster? Parkinson's Disease, Movement Vigor, and Implicit Motivation

Mazzoni¹,

Hristova²,

Krakauer³

2007

J. Neurosci.

493

413

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People generally select a similar speed for a given motor task, such as reaching for a cup. One well established determinant of movement time is the speed-accuracy trade-off: movement time increases with the accuracy requirement. A second possible determinant is the energetic cost of making a movement. Parkinson's disease (PD), a condition characterized by generalized movement slowing (bradykinesia), provides the opportunity to directly explore this second possibility. We compared reaching movements of patients with PD with those of control subjects in a speed-accuracy trade-off task comprising conditions of increasing difficulty. Subjects completed as many trials as necessary to make 20 movements within a required speed range (trials to criterion, N c ). Difficulty was reflected in endpoint accuracy and N c . Patients were as accurate as control subjects in all conditions (i.e., PD did not affect the speed-accuracy trade-off). However, N c was consistently higher in patients, indicating reluctance to move fast although accuracy was not compromised. Specifically, the dependence of N c on movement energy cost (slope S N ) was steeper in patients than in control subjects. This difference in S N suggests that bradykinesia represents an implicit decision not to move fast because of a shift in the cost/benefit ratio of the energy expenditure needed to move at normal speed. S N was less steep, but statistically significant, in control subjects, which demonstrates a role for energetic cost in the normal control of movement speed. We propose that, analogous to the established role of dopamine in explicit reward-seeking behavior, the dopaminergic projection to the striatum provides a signal for implicit "motor motivation."

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Section: Discussionsupporting

confidence: 81%

Why Don't We Move Faster? Parkinson's Disease, Movement Vigor, and Implicit Motivation

Mazzoni¹,

Hristova²,

Krakauer³

2007

J. Neurosci.

493

413

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“…This finding is consistent with the results of previous studies which have shown prolonged movement times for patients with Parkinson's disease (Angel et al, 1970;Brumlik & Boshes, 1966;Flowers, 1975). In the context of the results of the present experiment, the slowness of patients in performing complex movements can be attributed, in part, to a less efficient rate of processing feedback but more importantly to difficulty in preparing the response prior to initiation.…”

Section: Discussionsupporting

confidence: 93%

“…In all conditions the reaction times of the Parkinsonian patients were consistently and significantly longer than those of the control subjects. Previous studies have shown Parkinson's disease patients to be delayed in their reactions to auditory, tactile and visual stimuli (Angel et al, 1970;Brumlik & Boshes, 1966;Dinnerstein et al, 1962).…”

Section: Discussionmentioning

confidence: 99%

“…Abramsky, Lavy, & Carmon, 1971;Bowen, Brady, & Yahr, 1973;Perret, Eggenberger, & Siegfried, 1970;Pilling, Baker, Iverson, Iverson, & Robbins, 1975). However, attempts to specify the nature of the deficit in terms of the mechanisms of motor control and types of processes that are disrupted have not been definitive (Angel, Alston, & Higgins, 1970;Brumlik & Boshes, 1966;Dinnerstein, Frigyesi, & Lowenthal, 1962;Flowers, 1975Flowers, , 1976Flowers, , 1978aHiggins, 1970;Lee & Tatton, 1975;Talland & Schwab, 1964). The various explanations which have been proposed for the locus of abnormal function in Parkinson's disease are limited in terms of the range of underlying motor processes considered and the overt movement characteristics accounted for.…”

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confidence: 99%

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Processing of proprioceptive information in Parkinson's disease patients

Glencross

Tsouvallas

1984

Australian Journal of Psychology

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The present study is concerned with a comparison of Parkinson's disease patients and normal subjects on a number of simple and choice reaction time tasks in accordance with Sternberg's interactive procedures. The results indicated that the motor disorder in Parkinson's disease was at the level of output processing and related to the inability of central mechanisms to select and organize responses. Further, the results suggested that patients had difficulty in formulating complex plans or programmes for action.

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“…Simple objective tests, requiring no specialised equipment beyond, for example a stop watch, tape measure, peg board, pen and paper, or buttons and button holes, have frequently been advocated for inclusion in the outcome criteria of clinical trials in Parkinson's disease (e.g., Broe & Caird, 1973;Brumlik & Boshes, 1966;Calne et al, 1971;Mawdsley, 1970;Mindham, 1976;Nutt et al, 1984;Walker et al, 1972). However, there is little information on their sensitivity to and specificity for treatment effects, and as to their reliability.…”

Section: Discussionmentioning

confidence: 99%

Objective outcome criteria in trials of anti‐parkinsonian therapy in the elderly: sensitivity, specificity and reliability of measures of brady‐ and hypo‐kinesia.

Bowes

Clark

Charlett

et al. 1991

Brit J Clinical Pharma

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1. We compare the sensitivity and specificity of chosen outcome criteria in a placebo‐controlled, randomised cross‐over study of the efficacy of maintenance therapy with the levodopa/carbidopa combination (Sinemet Plus) alone. Patients were characterised by having idiopathic Parkinsonism with no overt fluctuations in control in relation to individual doses of medication. 2. The effect of omission of a morning dose of maintenance therapy on simple timed tests of mobility and manual dexterity, and on distance/time parameters of gait was studied in fourteen patients (aged 64 to 88 years). Measurements made 2, 4 and 6 h after morning active and placebo treatments were standardised by taking the pre‐treatment measurement on that day as baseline. 3. In a linear model, which allowed for the structure of the study, neither the total time taken by each patient to get up from a chair, walk an individually set distance, turn, return to and sit in the chair, nor the rate of progress at fastening the same set of buttons, was sensitive to the treatment effect. 4. Three of the gait parameters, free walking speed, mean stride length and mean double support time, were sensitive to the treatment effect. Correction for the speed of each walk, caused some reduction in the sensitivity of stride length to treatment effect, but that of double support time remained. Speed, and double support time or stride length, appeared to be complementary in defining the treatment effect. 5. The linear modelling revealed the complexity of the treatment effect. Although active treatment, by comparison with placebo, increased free walking speed (P = 0.019), the more levodopa found in the plasma following treatment, (P = 0.0005) and the greater the increment in the concentration of its peripheral metabolite, 3‐O‐methyldopa (P = 0.006), the less the beneficial effect. This model may reflect reduced uptake into the brain and/or an adverse effect of parent drug or a metabolite. 6. The specificity of free walking speed for the treatment effect was good, as was that of mean stride length, after it had been corrected for speed of each walk, and of mean double support time, after correction for speed and incorporation of the change in lying blood pressure accompanying treatment into the model. 7. The measurements of gait parameters were ranked according to reliability.(ABSTRACT TRUNCATED AT 400 WORDS)

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The mechanism of bradykinesia in parkinsonism

Cited by 36 publications

References 0 publications

Why Don't We Move Faster? Parkinson's Disease, Movement Vigor, and Implicit Motivation

Why Don't We Move Faster? Parkinson's Disease, Movement Vigor, and Implicit Motivation

Processing of proprioceptive information in Parkinson's disease patients

Objective outcome criteria in trials of anti‐parkinsonian therapy in the elderly: sensitivity, specificity and reliability of measures of brady‐ and hypo‐kinesia.

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