Mark,

Thanks so much for the response! You are right, there are no clinical studies on humans studying Keto's effect on TBI. Also most of the well published studies are on Epilepsy, as you said.

Nevertheless, some of the studies on the Keto diet are positively intriguing if I may say. Just knowing that there is a diet that has neuro-protective effects is something of interest to me as a TBI sufferer. While as you said, the theory (in humans) and evidence (in rats) suggest benefits in the short interval around TBI, the impact outside this interval is not known. But I wonder whether the neuroprotective effects found in other studies are not tempting enough to try (and trial) the diet.

This paper:
Neuroprotective and disease-modifying effects of the ketogenic diet
cites several studies uncontrolled studies in humans on the impact of keto on Parkinson and Alzheimer. To quote the "the ketogenic diet can provide symptomatic and disease-modifying activity in a broad range of neurodegenerative disorders including Alzheimer’s disease and Parkinson’s disease" The studies in humans are cited in the paper.

Then you hear a lot of theory from respectable folks on how keto can help the brain heal, protect, and reduce depression:
Your Brain on Ketones | Psychology Today
The fat-fueled brain: unnatural or advantageous? - Scientific American Blog Network

No hard evidence of any sort. But good to keep an eye on this. I might experiment with this. Have you seen anyone here with TBI trying Keto?