Oral processing speed as a key mechanism in the relationship between neurological risk and adaptive functioning in survivors of pediatric brain tumors

Abstract

Purpose: Brain tumor (BT) survivors are at risk for difficulties with adaptive functioning (AF). Recent work has associated neurological risk with poorer AF outcomes using the Neurological Predictor Scale (NPS), a quantification of neurological risk factors. Survivors also have poorer attention, processing speed, and working memory, which are all important for AF. The current study examined whether these cognitive constructs explain the relationship between the NPS and AF in survivors. Methods: Ninety-five adult BT survivors and 135 healthy controls were recruited from the Atlanta area. The Oral Symbol Digits Modalities test was used to measure processing speed, Digit Span Backward assessed working memory, and Digit Span Forward measured attention. Informants completed the Scales of Independent Behavior (SIB-R) to measure AF. Group differences and correlations were assessed, and the PROCESS macro for SPSS tested indirect effects. Results: Survivors were significantly lower on AF and cognitive measures compared with controls. Attention span and processing speed had significant indirect effects in relationship between NPS and AF individually, but processing speed was the only variable with a significant indirect effect when all cognitive variables were included in the model. The NPS and processing speed together account for approximately 39% of variance in AF outcomes. Conclusions: BT survivors in our sample have lower AF than controls, and processing speed appears to be particularly important in explaining the relationship between neurological risk and AF. In the future, the development of interventions aimed at increasing young adult independence should target both cognitive processing speed and AF skills.

Inhibition explains the relationship between the efficiency of brain networks and adaptive outcomes in pediatric brain tumor survivors.

“…Cognitive deficits seen in pediatric brain tumor survivors are often accompanied by difficulties with adaptive functioning (AF) or an individual’s ability to complete activities of daily living (ADLs) and care for themselves (King & Na, 2016; Semmel et al, 2020). AF includes personal functions, such as self-care and mobility, as well as interpersonal functions, such as communication and socialization (Sparrow et al, 2016).…”

“…Research has shown that commonly observed cognitive deficits in brain tumor survivors are related to and predict AF weaknesses in this population (King, Smith, et al, 2015; Panwala et al, 2019; Semmel et al, 2020). For example, multiple studies have implicated processing speed in AF outcomes in pediatric brain tumor survivors and other populations (Panwala et al, 2019; Semmel et al, 2020).…”

Processing Speed and Time since Diagnosis Predict Adaptive Functioning Measured with WeeFIM in Pediatric Brain Tumor Survivors

“…Papazoglou et al demonstrated that attention span predicted the communication score in a cerebellar population of pediatric BT [ 14 ]. Semmel et al found a significant indirect effect in a BT sample between the cognitive predictors of attention span and processing speed (PS), and neurological condition and AF; taken together, however, the neurological risk and PS had the power to explain 39% of the variance in the AF scores [ 15 ].…”

“…PS deterioration is mainly caused by a disruption in the white matter, which is extremely important for the diffusion of action potentials, but it is also particularly vulnerable to toxic and physical agents, such as radiation [ 18 , 19 ]. Research on pediatric traumatic brain injury (TBI) patients suggests that PS underlies AF abilities [ 13 , 15 ] and that PS is an important mediator between AF and TBI [ 12 ].…”

“…Papazoglou et al demonstrated that attention span predicted the communication score in a cerebellar population of pediatric BT [14]. Semmel et al found a significant indirect effect in a BT sample between the cognitive predictors of attention span and processing speed (PS), and neurological condition and AF; taken together, however, the neurological risk and PS had the power to explain 39% of the variance in the AF scores [15]. PS is the speed at which mental operations are performed [16], and it is one of the most compromised functions in pediatric BT patients [7], even when cognitive functioning falls within the average range [17].…”