Cognitive impairment correlated strongly with reduced thalamic volume and temporal lobe cortical thickness in patients with pediatric-onset multiple sclerosis (MS), according to findings published in the Egyptian Journal of Neurology, Psychiatry and Neurosurgery.

Researchers analyzed the level of cognitive impairment as it related to brain volumetric measurements of 50 patients with pediatric-onset MS ranging from 16 to 35 years of age (onset of MS was before 18 years of age) compared to 50 healthy control participants.

Trained psychologists evaluated cognitive ability and intelligence using the neuropsychological Standford-Benit test, assessing verbal and nonverbal components of knowledge, quantitative reasoning, visual-spatial processing, working memory, and fluid reasoning. The investigators calculated thalamic volume and temporal lobe cortical thickness from magnetic resonance imaging scans using a computer program called FreeSurfer.


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The patients with pediatric-onset MS demonstrated significantly reduced left and right temporal lobe cortical thickness in specific regions compared with the control group, including the superior temporal, middle temporal, inferior temporal, fusiform, and parahippocampal regions. Average left- and right-sided temporal lobe cortical thickness in the pediatric-onset MS group were 2.46±0.16 and 2.56±0.16, respectively, as compared to 2.85±0.14 and 2.86±0.15, respectively, in the control group (P <.001).

The patients with pediatric-onset MS demonstrated significantly reduced left and right sided thalamic volumes compared with the control group (left: 0.0039±0.0006 vs. 0.0053±0.0006; P <.001; right: 0.0032±0.0006 vs. 0.0052±0.0007; P <.001).

Average temporal lobe cortical thickness on the left correlated with nonverbal verbal-fluid reasoning (P =.041), nonverbal quantitative reasoning (P =.003), verbal visual-spatial processing (P =.011), full-scale intelligence quotient ([IQ]; P =.003), nonverbal IQ (P =.027), and verbal IQ (P =.018). Average temporal lobe cortical thickness on the right correlated with full-scale IQ (P =.036), nonverbal IQ (P =.041), and verbal IQ (P =.043).

Right side parahippocampal thickness correlated with verbal-fluid reasoning in nonverbal tests. Inferior temporal lobe thickness correlated with knowledge (P =.011). Both left and right-sided thalamic volumes correlated with nonverbal visual-spatial processing (P =.032; P =.039, respectively) and verbal quantitative reasoning (P =.019; P =.002, respectively).

“The onset of [MS] during developmental age makes pediatric patients particularly susceptible to cognitive impairment, resulting from both disease-related damage and failure of age-expected brain growth,” the authors said. “[Pediatric-onset MS] affects specific brain areas such as thalamus and cortical thickness of temporal lobes regarding their volume and thickness which influence the neuropsychological evaluation detected by Standford–Benit test.”

Reference

Ahmed NS, AbdAllah MA, Nassef AM, Mohamed AEA, Nada MA. Cognitive impairment in paediatric onset multiple sclerosis and its relation to thalamic volume and cortical thickness of temporal lobe by magnetic resonance imaging. Egypt J Neurol Psychiatr Neurosurg. 2022;58(1):59. doi:10.1186/s41983-022-00492-8