Ataxia Rating Scales Reveal Increased Scores in Very Preterm Born 5–6-Year-Old Preschool Children and Young Adults

Very preterm (VP) children and adults had higher total scores in ataxia rating scales (ARS) compared to term controls. Preterm birth is associated with higher scores in ARS. In addition, differences prevailed into young adulthood. Both scales were equally able to identify group differences with effects sizes being larger in children. Compared to controls, scores in the subscale posture and gait showed most consistent differences between groups. Gestational age at birth was negatively associated with ARS total scores in both children and adults.

In line with our findings, previous studies found a 3–4 times increased risk of mild to moderate motor problems in VP children compared to the general pediatric population [5]. VP adults had an 8–9 times increased likelihood to score above 0 in ARS compared to controls, which suggests an increased risk of difficulties in coordination and balance.

ARS offer easy to apply, standardized, and quantifiable instruments to identify soft neurological signs of difficulties in coordination and balance.

Of note, healthy children also show higher scores in ARS up to an age of 12 years [16, 17], which are likely due to the development of the sensory-motor systems [9, 10]. In line with this, healthy term-born children also scored higher in ARS in this study [16, 17]. However, both VP children and adults scored significantly higher in the ARS than controls, indicating deficits in coordination and balance, which may be explained by an aberrant development of brain areas involved in motor control including but not limited to the cerebellum. Dewey et al. described that preterm children at risk for DCD had volume reduction in motor areas including cerebral cortex, cerebellum, and basal ganglia [19]. Furthermore, Lahti et al. described an association between diffusion tensor matrix at term-equivalent age of the corpus callosum, corona radiata, and optic radiation with motor performance in 11-year-old preterm children [31]. Alterations in these brain regions are well known in VP infants, referred as encephalopathy of prematurity [3]. In addition to cerebral injury, there is increasing evidence of cerebellar involvement [3]. The most common alteration associated with prematurity is a symmetric volume reduction of the cerebellar hemispheres without focal lesions [32, 33]. Tam et al. demonstrated an association between volume reduction on magnetic resonance imaging (MRI) at term-equivalent age and an 8–10 times fold increased risk for truncal hypotonia, postural instability, and patellar hyperreflexia at the age of 18 months [33].

VP adults scored significantly higher in ARS than controls indicating that difficulties in coordination and balance may prevail until young adulthood. The medial region of the cerebellum (vermis) plays a central role in balance and locomotion [34, 35]. The vermis of the cerebellum shows a selective vulnerability for hypoxia especially in neonates [36]. This may explain why impairments in posture and gait prevail in adulthood in VP born individuals. Likewise, impairments of posture and gait are the most common symptoms in degenerative cerebellar ataxias [37].

Persisting motor problems were also reported in a Norwegian cohort study of very low birth weight born children. Evensen et al. discovered that in the preterm group, one out of four children had motor problems in the M-ABC (scores below the 5th percentile), persisting until 23 years of age [38].

Mild motor problems, unexplained by neurological conditions, with an impact on daily activities and age-appropriate participation are described as DCD [21]. Difficulties in coordination and balance are among the symptoms of DCD, for which VP children are especially at risk [18, 21]. However, there is a lack of clearly defined diagnostic criteria and diagnostic tools to confirm this diagnosis. Children with DCD and their families often have long time- and cost-consuming ways until the diagnosis is defined.

The application of ARS reliably revealed difficulties in coordination and balance in VP participants in the present study. Thus, it may a useful screening tool to decide which children should be tested with more extended instruments to diagnose motor problems such as the M-ABC-2 and BOT-2 [23].

We could also show a high correlation between total scores of both ARS. Whereas ICARS takes approximately 10–15 min to apply, SARA is briefly assessed in 4–5 min, but does not include oculomotor function [13, 15]. Since SARA takes only one-third of the time required for ICARS, it may be most suitable to be integrated into follow-up care to screen for cerebellar dysfunction with difficulties in coordination and balance.

Children’s motor abilities and physical performance have been found to affect their self-esteem, mental health, academic achievement, and acceptance by peers [19, 22, 39]. VP children have a 3–4 times fold increased risk of developing psychiatric disorders [6]. Thus, being clumsy and having significant deficits in coordination and balance, may put preterm children at further risk of social-emotional maladjustment, including difficulties with peers [40]. It is of great importance to identify children with these problems to intervene early and prevent later maladjustment [18, 20, 21, 39, 40]. Increased awareness and knowledge of health-care professionals involved in the follow-up care of VP children may help to apply early interventions, which improve coordination and balance in physical training. Interventions may not only train VP children’s physical abilities but, in turn, may also increase their self-esteem and social-emotional development.

The aftermath of perinatal impairment of cerebellar growth/cerebellar injury came into focus during the last decade. In addition to motor impairment, the developmental dysfunction of the cerebellum seems to have a great impact on long-term cognitive, behavioral, and social-emotional development of individuals [41]. Prematurity appears to be associated with a developmental form of the cerebellar cognitive affective syndrome [41]. Therefore, it would be reasonable to assess VP born adults with the Cerebellar Cognitive Affective Syndrome Scale (CCAS-S) [42], and to develop a CCAS-S for children.

This study has some limitations: First we did not follow one sample to investigate ARS longitudinally from childhood into adulthood. However, we increased comparability between children and adult groups by recruiting participants based on the same inclusion and exclusion criteria. Second, high scores in ARS are not exclusively indicative of cerebellar dysfunction but may also indicate other brain pathologies, such as injuries in basal ganglia or motor cortex, and symptoms of impaired proprioception, muscle tone, vestibular- and visual-motor control [43]. Third, a dose–response relation between ARS scores and gestational age was not done across the whole gestation spectrum. Further investigations with larger sample sizes and longitudinal studies of VP children are needed and planned.

留言 (0)

沒有登入
gif