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Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome.

Skirrow C, Cross JH, Harrison S, Cormack F, Harkness W, Coleman R, Meierotto E, Gaiottino J, Vargha-Khadem F, Baldeweg T - Brain (2014)

Bottom Line: Pre- to post-surgical change in memory function was not associated with any indices of brain structure derived from MRI.However, better verbal memory at follow-up was linked to greater post-surgical residual hippocampal volumes, most robustly in left surgical participants.However, outcome was linked to the anatomical integrity of the temporal lobe memory system, indicating that compensatory mechanisms are constrained by the amount of tissue which remains in the operated temporal lobe.

View Article: PubMed Central - PubMed

Affiliation: 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK.

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A diagrammatic overview of memory change before and after left temporal lobe surgery in children. Interpretation of our findings in the context of previous research: in dashed lines we present a schema of our findings in the non-surgical sample, and in solid lines findings from the surgical sample. Normal development is indicated with a dashed black line. Previous research from Helmstaedter and Elger (2009) showed an earlier and lower developmental peak of memory function for individuals with temporal lobe epilepsy, compared with their healthy peers. Gleissner et al. (2005) showed a short-lived decline in memory function at 3 months after temporal lobe surgery, resolving after just 1 year in children. Our findings indicate no differences in verbal memory outcome between children who undergo left temporal lobe surgery and those that do not, but indicate significant post-surgical improvements in visual memory function. Shading: Representation of the variability in the postoperative developmental trajectory of memory which may be optimized by tailoring of resections within the temporal lobe structures critical to declarative memory (brain image: showing in yellow the left temporal pole subserving semantic memory, and in red the left hippocampus subserving verbal episodic memory).
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awu313-F3: A diagrammatic overview of memory change before and after left temporal lobe surgery in children. Interpretation of our findings in the context of previous research: in dashed lines we present a schema of our findings in the non-surgical sample, and in solid lines findings from the surgical sample. Normal development is indicated with a dashed black line. Previous research from Helmstaedter and Elger (2009) showed an earlier and lower developmental peak of memory function for individuals with temporal lobe epilepsy, compared with their healthy peers. Gleissner et al. (2005) showed a short-lived decline in memory function at 3 months after temporal lobe surgery, resolving after just 1 year in children. Our findings indicate no differences in verbal memory outcome between children who undergo left temporal lobe surgery and those that do not, but indicate significant post-surgical improvements in visual memory function. Shading: Representation of the variability in the postoperative developmental trajectory of memory which may be optimized by tailoring of resections within the temporal lobe structures critical to declarative memory (brain image: showing in yellow the left temporal pole subserving semantic memory, and in red the left hippocampus subserving verbal episodic memory).

Mentions: Our findings link brain structure indices to memory outcome at follow-up rather than change in memory function from pre- to post-surgery. This may reflect constraints on long-term compensation and recovery processes in childhood and adolescence. Our findings in a sample of children differ with respect to previous reports in adults, which emphasize post-surgical loss of function in association with volumetric brain changes (Baxendale et al., 2000; Graydon et al., 2001). We summarize our findings and interpretation in Fig. 3.Figure 3


Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome.

Skirrow C, Cross JH, Harrison S, Cormack F, Harkness W, Coleman R, Meierotto E, Gaiottino J, Vargha-Khadem F, Baldeweg T - Brain (2014)

A diagrammatic overview of memory change before and after left temporal lobe surgery in children. Interpretation of our findings in the context of previous research: in dashed lines we present a schema of our findings in the non-surgical sample, and in solid lines findings from the surgical sample. Normal development is indicated with a dashed black line. Previous research from Helmstaedter and Elger (2009) showed an earlier and lower developmental peak of memory function for individuals with temporal lobe epilepsy, compared with their healthy peers. Gleissner et al. (2005) showed a short-lived decline in memory function at 3 months after temporal lobe surgery, resolving after just 1 year in children. Our findings indicate no differences in verbal memory outcome between children who undergo left temporal lobe surgery and those that do not, but indicate significant post-surgical improvements in visual memory function. Shading: Representation of the variability in the postoperative developmental trajectory of memory which may be optimized by tailoring of resections within the temporal lobe structures critical to declarative memory (brain image: showing in yellow the left temporal pole subserving semantic memory, and in red the left hippocampus subserving verbal episodic memory).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4285190&req=5

awu313-F3: A diagrammatic overview of memory change before and after left temporal lobe surgery in children. Interpretation of our findings in the context of previous research: in dashed lines we present a schema of our findings in the non-surgical sample, and in solid lines findings from the surgical sample. Normal development is indicated with a dashed black line. Previous research from Helmstaedter and Elger (2009) showed an earlier and lower developmental peak of memory function for individuals with temporal lobe epilepsy, compared with their healthy peers. Gleissner et al. (2005) showed a short-lived decline in memory function at 3 months after temporal lobe surgery, resolving after just 1 year in children. Our findings indicate no differences in verbal memory outcome between children who undergo left temporal lobe surgery and those that do not, but indicate significant post-surgical improvements in visual memory function. Shading: Representation of the variability in the postoperative developmental trajectory of memory which may be optimized by tailoring of resections within the temporal lobe structures critical to declarative memory (brain image: showing in yellow the left temporal pole subserving semantic memory, and in red the left hippocampus subserving verbal episodic memory).
Mentions: Our findings link brain structure indices to memory outcome at follow-up rather than change in memory function from pre- to post-surgery. This may reflect constraints on long-term compensation and recovery processes in childhood and adolescence. Our findings in a sample of children differ with respect to previous reports in adults, which emphasize post-surgical loss of function in association with volumetric brain changes (Baxendale et al., 2000; Graydon et al., 2001). We summarize our findings and interpretation in Fig. 3.Figure 3

Bottom Line: Pre- to post-surgical change in memory function was not associated with any indices of brain structure derived from MRI.However, better verbal memory at follow-up was linked to greater post-surgical residual hippocampal volumes, most robustly in left surgical participants.However, outcome was linked to the anatomical integrity of the temporal lobe memory system, indicating that compensatory mechanisms are constrained by the amount of tissue which remains in the operated temporal lobe.

View Article: PubMed Central - PubMed

Affiliation: 1 Cognitive Neuroscience and Neuropsychiatry Section, Developmental Neurosciences Programme, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK 2 Great Ormond Street Hospital NHS Trust, Great Ormond Street, WC1N 3JH, UK.

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Related in: MedlinePlus