Serial cognitive change patterns across time after temporal lobe resection for epilepsy

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurosurgery

Background:

• Temporal lobe epilepsy (TLE) surgery can impact cognitive function.
• Understanding long-term cognitive outcomes post-resection is crucial for patient management.
• Previous studies often focused on short-term or group-level changes.

Purpose of the Study:

• To longitudinally assess cognitive outcomes (general cognitive status and memory) at the group and individual levels, 10 years after temporal lobe resection for epilepsy.
• To evaluate changes from baseline to medium-term and long-term follow-up.
• To clarify the interpretation of initial postoperative cognitive changes.

Main Methods:

• Longitudinal study of 25 patients undergoing temporal lobe resection for epilepsy.
• Cognitive assessments at baseline, medium-term follow-up (T2, median 2.7 years), and long-term follow-up (T3, median 9.8 years).
• Analysis included group-level changes (IQ, memory) and individual-level changes compared to matched controls.

Main Results:

• At the group level, IQ significantly improved over time (p<0.0001), partly attributed to practice effects; memory variables did not show significant group changes.
• Individual-level analysis at medium-term follow-up revealed cognitive decrements in 12-29% of patients and increments in 8-21%.
• These proportions of individual change diminished by long-term follow-up (0-12% decrements, 0-16% increments), with a predominant pattern of return toward baseline for Performance IQ and verbal memory.

Conclusions:

• Initial postoperative cognitive changes (increments or decrements) after temporal lobe resection are complex and may be transient.
• Long-term cognitive evaluation reveals a tendency for individual performance to normalize towards baseline levels.
• Comprehensive, longitudinal assessment at both group and individual levels is essential for accurately interpreting cognitive outcomes after epilepsy surgery.