How Does Growth Hormone Deficiency Affect Brain Structure?

Study Also Looked at Growth Hormone Deficiency and Motor Function and Cognition

Chemical structure of human growth hormone Even though it’s known that growth hormone insulin-like growth factor-1 is key in normal brain growth, less is known about how the brain structure is impacted by growth hormone deficiency.  A study examined this; the results were published in Brain in January 2012 in the article “Effect of growth hormone deficiency on brain structure, motor function and cognition.”

In the study, there were 15 children with isolated growth hormone deficiency (mean age: 8.8 years; peak growth hormone < 6.7 µg/l [mean: 3.5 µg/l]).  There were also 14 controls with idiopathic short stature (mean age: 8.4 years; peak growth hormone > 10 µg/l [mean: 15 µg/l] and normal growth rate).

The children had cognitive assessment, diffusion tensor imaging, and volumetric magnetic resonance imaging before beginning growth hormone treatment.  Using Freesurger, the following were measured:  total brain, corpus callosal, hippocampal, thalamic, and basal ganglia volume.  Additionally, fractional anisotropy, which is a marker of white matter structural integrity, images were aligned; researcher performed tract-based spatial statistics.

Those children with isolated growth hormone deficiency had lower Full-Scale IQ (p<0.01) when compared to controls.  Also when compared to controls, they had lower Verbal Comprehension Index (p < 0.01), Processing Speed Index (p < 0.05), and Movement-Assessment Battery for Children (p < 0.008).

The standard deviation scores of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 were significantly correlated with Verbal Comprehension Index scores (p < 0.03 and p < 0.02, respectively) for children with isolated growth hormone deficiency.

It was also seen that the splenium of the corpus callosum, left glovus pallidum, thalamus, and hippocampus were significantly smaller (p < 0.01) in children with isolated growth hormone deficiency.

The fractional anisotropy of the corticospinal tract (bilaterally: p < 0.045 and p < 0.05) and corpus callosum (p < 0.05) were significantly lower in those with isolated growth hormone deficiency.

Other significant correlations seen were:  basal ganglia volumes and bilateral corticospinal tract fractional anisotrophy with Movement-Assessment Battery for Children scores, and corpus callosum fractional anisotropy with Full-Scale IQ and Processing Speed Index.

Cognitive function and motor performance deficits were related to white matter abnormalities in the corpus callosum and corticospinal tract, as well as to lower thalamic and globus pallidum volumes.

The researchers suggest follow-up studies to confirm that growth hormone deficiency significantly affects brain structures, cognitive function, and motor performance. 

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