Eight subjects with carpal tunnel syndrome (CTS) (47.13 ± 7.83 years) and 8 matched controls (46.29 ± 7.27 years) manipulated a test object fitted with an accelerometer and force sensor, both before and after hand muscle fatigue. Grip force and object acceleration were recorded and used to calculate grip force control variables that included Grip Force Peak, Safety Margin, and Time to Grip Force Peak. Individuals with CTS exhibited a higher Safety Margin (p = .010) and longer Time to Peak of Grip Force (p = .012) than healthy controls during object manipulation. Once fatigued, both groups significantly decreased their grip force to perform the task (Grip Force Peak; p = .017 and Safety Margin; p < .001). Nevertheless, individuals with CTS maintained an unnecessarily high safety margin. Our results suggest that CTS can adversely affect how the central nervous system regulates grip force, which might aggravate the inflammatory process and exacerbate the symptoms of this disease.
Daniela JS Mattos, Susana Cristina Domenech, Noé Gomes Borges Junior and Marcio José Santos
Vennila Krishnan, Paulo Barbosa de Freitas and Slobodan Jaric
We investigated hand function in mildly involved multiple sclerosis (MS) patients (N = 16; Expanded Disability Status Scale 1–5, 9-hole peg test 14–32 s) during static and dynamic manipulation tasks using an instrumented device. When compared with healthy controls (N = 16), the patients revealed impaired task performance regarding their ability to exert prescribed patterns of load force (L; force acting tangentially at the digits-object surface). Regarding the coordination of grip force (G; normal component) and L, the data only revealed an elevated G/L ratio, although both the G and L coupling (maximum correlation coefficients and the time lags between them) and the G modulation (gain and offset of G with respect to L) remained comparable in the two groups. Finally, most of the data suggested no MS-specific effects of switching from uni- to bimanual tasks, from available visual feedback to deprived feedback conditions. We conclude that the deterioration in the ability for precise control of external forces and overgripping could precede the decoupling of G and L and decreased G modulation in early phases of the disease. The results also suggest that the applied methodology could be sensitive enough to detect mild levels of impairment of hand function in MS and, possibly, other neurological diseases.
Loes Janssen, Céline Crajé, Matthias Weigelt and Bert Steenbergen
We examined anticipatory motor planning and the interaction among both hands in a discrete bimanual task. To this end, participants had to grasp and manipulate two cylindrical objects simultaneously under varying conditions in which (a) the grip selection requirements, i.e., orientation of the to-be-grasped objects, differed between the two hands and (b) the type of grip for one hand was preinstructed, while the grip for the other hand was free choice. Results showed that participants, when grasping for two bars with a free grip choice, prioritized planning for comfortable end postures over symmetry of movement execution. Furthermore, when participants were free to choose a grip for their left hand, but were instructed on how to grasp an object with their right hand, we found no interaction between the grip selections of both hands, suggesting that motor planning proceeds independently for both hands.
Sara M. Scharoun, David A. Gonzalez, Eric A. Roy and Pamela J. Bryden
.actpsy.2014.06.004 Coelho , C.J. , Studenka , B.E. , & Rosenbaum , D.A. ( 2014 ). End-state comfort trumps handedness in object manipulation . Journal of Experimental Psychology: Human Perception and Performance, 40 ( 2 ), 718 . PubMed Cohen , J. ( 1988 ). Statistical power analysis for the
Rainer Blank and Joachim Hermsdörfer
Fast force changes with hand-held objects are an important prerequisite for object manipulation in everyday life. This study examines the development of fastest isometric force changes in a precision grip. One hundred sixty-five children (76 girls, 89 boys), 3–14 years, without neurological abnormalities increased and decreased repetitively isometric grip forces as rapidly as possible by their dominant hand using a small cylindrical pinch grip object (20 g). The frequency of repetitive force changes increased in a linear way from the age of 4 years until about 12 years by 0.23 Hz per year (r 2 = .54) without noticeable gender difference. The ratio of the duration of force increase and decrease slightly declined from 1.05 (4-year-olds) to 0.95 (11- to 14-year-olds). The development of force amplitudes and the mean force were more variable. Temporal parameters become less variable with age, whereas force parameters become more variable. In particular, the temporal parameters of fastest isometric force changes are best predictors for developmental changes. Fastest isometric force changes may be an important basic capacity for fast object manipulation, particularly in young children and in children with movement disorders.
Marcel Mutsaarts, Bert Steenbergen and Harold Bekkering
Anticipatory planning was examined in detail for a complex object manipulation task by capitalizing on both the complexity and the number of elements in the movement sequences in seven individuals with hemiparetic cerebral palsy (HCP) and seven left-handed control participants. Participants had to grasp a hexagonal knob using one of five possible grasping patterns as quicklly as possible following a starting cue (condition I), and sometimes, they had to rotate it subsequently either 60˚ or 120˚ clockwise or counterclockwise (condition II). In the first condition, the HCP participants appear to anticipate the comfort of the different grasping patterns before movement onset, as controls did. However, when the task consisted of more than one movement part, HCP participants did not complete their planning processes before movement onset, which was contrary to controls. Instead, the results suggest that they use a step-by-step planning strategy, that is, they planned the latter parts of a movement sequence as the movement unfolds. The results are discussed in the light of possible capacity limitations of an internal model for grip selection, and a recent model on the planning and on-line control of movement performance.
Kathrin Wunsch, Anne Henning, Gisa Aschersleben and Matthias Weigelt
The end-state comfort (ESC) effect signifies the tendency to avoid uncomfortable postures at the end of goal-directed movements and can be reliably observed during object manipulation in adults, but only little is known about its development in children. The aim of the present paper is to provide a review of research on the ESC effect in normally developing children and in children with various developmental disorders, and to identify the factors constraining anticipatory planning skills. Three databases (Medline, Scopus, and PubMed) and relevant journals were scrutinized and a step-wise analysis procedure was employed to identify the relevant studies. Thirteen studies assessed the ESC effect in children, ranging from 1.5–14 years of age. Nine out of these thirteen studies reported the ESC effect to be present in normally developing children, but the results are inconsistent with regard to children’s age and the kind of ESC task used. Some evidence even suggests that these planning skills are intact in children with developmental disorders. Inconsistencies between findings are discussed in the light of moderating factors like the number of action steps, precision requirements, familiarity with the task, the task procedure, motivation, sample size, and age, as well as the cognitive and motor development of the participants. Further research is needed to investigate the onset and the developmental course of ESC planning, as well as the interdependencies with other cognitive abilities and sensory-motor skills.
Janna M. Gottwald
This article critically reviews kinematic measures of prospective motor control. Prospective motor control, the ability to anticipatorily adjust movements with respect to task demands and action goals, is an important process involved in action planning. In manual object manipulation tasks, prospective motor control has been studied in various ways, mainly using motion tracking. For this matter, it is crucial to pinpoint the early part of the movement that purely reflects prospective (feed-forward) processes, but not feedback influences from the unfolding movement. One way of defining this period is to rely on a fixed time criterion; another is to base it flexibly on the inherent structure of each movement itself. Velocity—as one key characteristic of human movement—offers such a possibility and describes the structure of movements in a meaningful way. Here, I argue for the latter way of investigating prospective motor control by applying the measure of peak velocity of the first movement unit. I further discuss movement units and their significance in motor development of infants and contrast the introduced measure with other measures related to peak velocity and duration.
Editorial Editorial Richard Nichols 1 2008 12 1 1 2 10.1123/mcj.12.1.1 Original Research Impaired Object Manipulation in Mildly Involved Individuals with Multiple Sclerosis Vennila Krishnan * Paulo Barbosa de Freitas * Slobodan Jaric * 1 2008 12 1 3 20 10.1123/mcj.12.1.3 Research Effects of
2012 16 4 506 520 10.1123/mcj.16.4.506 Effect of Fatigue on Grip Force Control During Object Manipulation in Carpal Tunnel Syndrome Daniela JS Mattos * Susana Cristina Domenech * Noé Gomes Borges Junior * Marcio José Santos * 10 2012 16 4 521 536 10.1123/mcj.16.4.521 Development of Temporal and