Rate of force production and relaxation is impaired in patients with focal hand dystonia

Prodoehl, Janey; MacKinnon, Colum D.; Comella, Cynthia L.; Corcos, Daniel M.

doi:10.1016/j.parkreldis.2006.01.008

Cited by 17 publications

(11 citation statements)

References 30 publications

(54 reference statements)

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“…We had expected this result, as co-contraction is considered to be an important symptom of dystonia, 15 and previous research has shown that individuals with dystonia have difficulty activating and relaxing muscles on demand. [29][30][31] A closer look at the results, however, provides a more nuanced picture. Figure 4 shows a Kaplan-Meier plot of the distribution of cocontraction in both groups during the first block of testing (without visual feedback of co-contraction).…”

Section: Discussionmentioning

confidence: 99%

Visual Feedback Reduces Co-contraction in Children With Dystonia

2010

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Inappropriate muscle activation and co-contraction are important features in childhood dystonia, and clinical interventions are often targeted to reduce the excess muscle activation. Previous research has shown that visual biofeedback of muscle activity can help people to reduce excess muscle activation in a variety of motor disorders. To investigate the effectiveness of similar techniques for dystonia, we had participants perform a tracking task with and without visual feedback of co-contraction. Children with dystonia had greater levels of co-contraction than children without dystonia. Most importantly, individuals were able to reduce their co-contraction significantly when visual biofeedback was provided. These results indicate that children with dystonia are able to control co-contraction, at least to a certain extent, provided attention can be directed to the excess muscle activation. These results also suggest that methods of biofeedback focusing on inappropriate muscle activations might provide a clinical benefit for treatment of children with dystonia.

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Section: Discussionmentioning

confidence: 99%

Visual Feedback Reduces Co-contraction in Children With Dystonia

2010

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“…Second, slowness was also found in a previous study utilizing this exact group of participants with FHD performing an isometric task that did not have accuracy constraints. In that study we examined the ability of individuals with FHD to terminate force either passively (i.e., by relaxing) or actively (i.e., by rapidly reversing torque output) without regard to a target (Prodoehl et al, 2006b). Under both the contraction and relaxation task conditions, where accuracy was not a concern, dystonic participants were slower than controls.…”

Section: Discussionmentioning

confidence: 99%

“…These were the same participants as those whom we tested during some of our previous work (Prodoehl, Corcos, & Vaillancourt, 2006a; Prodoehl et al, 2006b, 2006c). Individuals with FHD were recruited from two surrounding medical centers.…”

Section: Methodsmentioning

confidence: 99%

“…For example, in the absence of dystonic posturing, individuals with FHD have been shown to be weaker than controls in producing maximal isometric wrist and elbow force (Prodoehl, Mackinnon, Comella, & Corcos, 2006c) and slower than controls in rapidly turning on and off submaximal isometric force at the wrist and elbow (Prodoehl, MacKinnon, Comella, & Corcos, 2006b). Because larger forces are required to rapidly move to targets at long distances compared to short distances, force production deficits may lead to greater impairment of movement at longer distances in individuals with dystonia.…”

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confidence: 99%

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Changes in the Relationship Between Movement Velocity and Movement Distance in Primary Focal Hand Dystonia

Prodoehl

Corcos

Leurgans

et al. 2008

Journal of Motor Behavior

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The authors examined the relationship between movement velocity and distance and the associated muscle activation patterns in 18 individuals with focal hand dystonia (FHD) compared with a control group of 18 individuals with no known neuromuscular condition. Participants performed targeted voluntary wrist and elbow flexion movements as fast as possible across 5 movement distances. Individuals with FHD were slower than controls across all distances, and this difference was accentuated for longer movements. Muscle activation patterns were triphasic in the majority of individuals with FHD, and muscle activation scaled with distance in a similar manner to controls. Cocontraction did not explain movement slowing in individuals with dystonia, but there was a trend toward underactivation of the 1st agonist burst in the dystonic group. The authors concluded that slowness is a consistent feature of voluntary movement in FHD and is present even in the absence of dystonic posturing. Underactivation of the 1st agonist burst appears to be the most likely reason to explain slowing. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptsuggests that dystonia is a disorder that also affects voluntary movement control, even in the absence of dystonic muscle spasms. Individuals with dystonia are slower than individuals with no known neuro-muscular condition at both wrist (MacKinnon, Velickovic, Drafta, Hesquijarosa, & Brin, 2004) and elbow joints (van der Kamp et al., 1989) during movement with one degree of freedom and during whole-arm movement (Agostino, Berardelli, Formica, Accornero, & Manfredi, 1992;Curra et al., 2000;Inzelberg, Flash, & Korczyn, 1990;Inzelberg, Flash, Schechtman, & Korczyn, 1995). However, single-joint studies have been concerned with movement distances of 30° or less, and researchers have examined no more than two target distances within a study (15° and 30°;van der Kamp et al., 1989). When ballistic selfpaced movements are performed over a wide range of movement distances in individuals with no known neuromuscular condition, movement velocity scales with movement distance. This relationship is approximately linear (Bahill, Clark, & Stark, 1975;Newell, Hancock, & Robertson, 1984). Pfann, Buchman, Comella, and Corcos (2001) showed the slope of the relationship between peak velocity and target distance to be impaired in basal ganglia disorders such as Parkinson's disease. Because dystonia is related to abnormal basal ganglia functioning, it is of interest to know whether the relationship between peak velocity and movement distance is also impaired in primary dystonia. It is also not clear whether muscle activation patterns are modulated appropriately across movement distance in individuals with dystonia.In addition to deficits in movement control, deficits in force control have also been shown in individuals with focal dystonia even when they do not manifest dystonic symptoms during the performance of a task. For example, in the absence of dystonic posturing, individuals with FHD ...

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“…They are less capable to regulate force properly indicating an impaired capacity to integrate sensory information into motor programming [5]. Moreover, they have difficulties to rapidly turn on and to voluntarily relax isometric force output of the wrist [6]. Writing pressure [7] and grip force on the writing pen are increased [8].…”

Section: Introductionmentioning

confidence: 99%

Botulinum neurotoxin treatment improves force regulation in writer's cramp

Zeuner

Knutzen

Pedack

et al. 2013

Parkinsonism & Related Disorders

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Writer's cramp patients show poor force regulation during handwriting, but also in other experimental tasks requiring fine motor control. Botulinum neurotoxin (BoNT) treatment is clinically effective in a substantial portion of writer's cramp patients, but the full mechanism of action remains enigmatic. BoNT possibly influences α- and γ-motoneurons through chemodenervation not only of extra-, but also intrafusal muscle fibres and might thus influence muscle spindle afferents. Hence, BoNT weakens injected muscles, but may also modulate sensory aspects of force control. Ten patients and 18 controls pressed their index finger on a force sensor tracking two visual targets: The first target consisted of five plateaus with successively higher force levels and alternated with ascending ramps. In the second target condition the same successive plateaus were to be reached by abrupt jumps. The generated force displayed as a time dependant curve. Root mean square of the difference between target and produced force level was calculated for each plateau / ramp / jump. Patients were treated with BoNT at week 4 and measured at baseline, weeks 2, 4, 6 and 8. Disturbed force regulation in patients for the plateaus and the second jump at baseline resolved after BoNT treatment, and the root mean square of force deviation decreased for the ramps. Fine force control was within the 95 % confidence interval of the control group after treatment. In conclusion, force regulation was disturbed in patients and improved after BoNT treatment. This is not compatible with a simple muscle weakening and might thus reflect improved sensorimotor integration.

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Rate of force production and relaxation is impaired in patients with focal hand dystonia

Cited by 17 publications

References 30 publications

Visual Feedback Reduces Co-contraction in Children With Dystonia

Visual Feedback Reduces Co-contraction in Children With Dystonia

Changes in the Relationship Between Movement Velocity and Movement Distance in Primary Focal Hand Dystonia

Botulinum neurotoxin treatment improves force regulation in writer's cramp

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