Effects of growth hormone (GH) replacement and cognitive rehabilitation in patients with cognitive disorders after traumatic brain injury

Objective: To assess the effects of growth hormone (GH) treatment combined with cognitive rehabilitation in patients with adult growth hormone deficiency (GHD) and cognitive disorders occurring after traumatic brain injury (TBI). Participants: Nineteen adult patients with TBI: GHD was found in 11 of them. Intervention: Patients were treated with GH (GHD; sc; 1 mg/day) or vehicle (controls; sc; 1 mg/day); daily cognitive rehabilitation therapy was performed in both groups for 3 months. Main outcome measures: The GHRH arginine test established GHD. The neuropsychological test WAIS was performed before commencing the treatment and 3 months after commencing it. Results: Controls achieved significant improvements in digits and in manipulative intelligence quotient (IQ) (p < 0.05 vs. baseline). GHD achieved significant improvements in more cognitive parameters: understanding, digits, numbers and incomplete figures (p < 0.05 vs. baseline) and similarities, vocabulary, verbal IQ, manipulative IQ and total IQ (p < 0.01). GHD reached significantly greater improvements than controls in similarities (p < 0.01) and in vocabulary, verbal IQ and total IQ (p < 0.05). Conclusion: GH administration significantly improved cognitive rehabilitation in GHD patients. Since at the end of treatment period plasma IGF-I levels were similar in both groups it is likely that exogenous GH administration is responsible for the significant differences found.