Perceived and actual motor competence of children treated for cancer with vincristine containing chemotherapy

To the Editor: Perceived motor competence is an important factor in self-esteem in children [1]. We recently showed that children with malignancies had impaired motor performance after vincristine containing chemotherapy [2]. Vincristine, which is used in treatment protocols for various childhood malignancies, causes polyneuropathy, which may lead to a decrease in muscle strength in upper and lower extremities. It is not known how children who have completed vincristine-containing chemotherapy perceive their motor competence and whether this affects their self-esteem. We evaluated the perceived motor competence and the actual motor performance of children treated with vincristine containing chemotherapy for acute lymphoblastic leukemia (ALL), Wilms tumor (WT), B-non-Hodgkin lymphoma or malignant mesenchymal tumor (MMT) [3–7]. Thirty-four boys and 19 girls aged 10.2 years ( 1.3), who had completed chemotherapy at least 1 year ago, filled out the m-CBSK [8]. The m-CBSK is an extended version of the athletic competence domain of the Self-Perception Profile for Children [1] and was developed for Dutch children aged 8–12 years. The median decile score for perceived motor competence in the survivors group was 6.0, which is not significantly different from reference values (P1⁄4 0.95). The motor domain was considered important by only 45% of the children versus 70% in the general population [8]. Motor performance scores, expressed as percentiles, were determined with the Dutch version of the Movement Assessment Battery for Children (movement-ABC) [9]. The median percentile score on the movement-ABC of the survivors group was 25.0, which was significantly lower than reference values (P< 0.001). There was a weak but significant correlation between movement-ABC score and perceived motor competence (rs 1⁄4 0.38, P1⁄4 0.01). In 77% of the cases (n1⁄4 41) the percentile score on the movement-ABC was lower than the perceived competence score (Fig. 1). Children with physical differences are suggested to be at risk for negative social perceptions and behaviors and loss of self-esteem and during chemotherapy children show dissatisfaction with their athletic performance [10]. We hypothesized that children who had been treated with vincristine containing chemotherapy for ALL, WT, B-non-Hodgkin lymphoma and MMT would have low perceived motor competence. However, the data showed that their perceived motor competence did not differ from healthy peers. The significant correlation between perceived competence and actual motor performance indicates that children who performed better on the motor test rated themselves more highly than those with lower scores. However, overrating of performance occurred in 77% of the children. An explanation for this tendency to ‘‘overrate’’ may be trying to avoid being pitied, or causing their parents to worry about them. Also they may wish to be normal, something that has been observed in a study of adolescent cancer survivors [11]. Although the children in this study may find motor competence of less importance and there is a tendency to overrate their competence, the majority of children appeared to be satisfied with their motor performance.