14 The Impact of Socioeconomic Status (SES) on Phonemic Fluency in Patients with Pediatric Brain Tumor (PBT)

Abstract

Objective:

Phonemic fluency, an important cognitive skill for everyday functioning, has been shown to decline in comparison to same-aged peers following pediatric cancer diagnosis and treatment, despite intact semantic fluency. More generally, socioeconomic status (SES) has recently been shown to be one of the strongest predictors of neuropsychological outcomes among pediatric oncology patients, with lower SES predicting worse intellectual and academic functioning. However, the association between SES and phonemic fluency within this population has yet to be explored. The main objective of this project was to determine whether SES (specifically estimated household income) significantly predicts phonemic fluency performance among patients with PBT, and it was hypothesized that higher SES would be associated with better phonemic fluency outcomes.

Participants and Methods:

136 participants with PBT ages 7-20 (x=14.15 years, SD=3.87), were administered phonemic fluency trials (either from the NEPSY - Second Edition or Delis-Kaplan Executive Function System, with no significant differences in performance between measures). The sample was 58.8% male and half Latino (50.0%), followed by Caucasian (30.1%), Asian American (7.4%), Black (6.6%), and Other (5.9%) ethnicity. All patients identified English as their primary and preferred language regardless of predominant household language, reducing the potential confounding impact of language. Given documented associations between PBT and lower intelligence following diagnosis and treatment, estimated intellectual functioning was included in the first block of hierarchical regression to isolate and further elucidate the potential contributing influence of SES on phonemic fluency. Median household income for specific neighborhoods was used as a proxy for SES, while Wechsler Matrix Reasoning (MR) was used as an estimate of general intellectual functioning given the high correlation between MR and full scale IQ.

Results:

Consistent with prior literature, phonemic fluency was lower than normative age expectations [t(135)=-3.653, p=.0002], though still within the average range clinically (x=8.93). As hypothesized, SES was positively correlated with phonemic fluency [r(136)=.219, p=.005]. Furthermore, SES significantly predicted phonemic fluency performance above and beyond estimated intelligence, accounting for a significant increase in variance (p=.020). Post-hoc analyses also revealed poorer phonemic fluency among participants with infratentorial brain tumors as compared to supratentorial brain tumors after controlling for SES, t(108)=-1.748, p=.042.

Conclusions:

Consistent with the known impact of SES on neuropsychological late effects among patients with pediatric cancer, phonemic fluency was positively correlated with SES among participants with PBT above and beyond estimated intelligence, suggesting the distinct role of SES on rapid verbal retrieval within this population. This has important implications for identifying patients at higher risk, helping to ensure timely provision of services and supports. Poorer phonemic fluency was also noted among patients with infratentorial (vs. supratentorial) brain tumors after controlling for SES, which may influence studies combining tumor location as the vast majority of PBTs are infratentorial. This supports prior literature demonstrating the need for increased cerebellar activation during phonemic (vs. semantic) retrieval. Additional research is needed to further explore these findings.