Severity of brain injury is related to cessation of dream recall and also to increased nightmares. Paper by Mark Blagrove and co-authors in Neuropsychologia.

Paper by Mark Blagrove and co-authors on how brain injury can result in dream recall being stopped, or for other, occurrence of nightmares to increase. Paper is available here. 
​Highlights

• Lesions to frontal and temporoparietal brain areas cause cessation of dream recall.
• 34.6 % of brain injured patients reported never dreaming, versus 7.1 % for controls.
• Dream cessation is predicted by the severity of brain injury.
• Nightmare frequency predicted by anxiety but negatively by brain injury severity.
• Recovery of dream experience may be predictive of more global brain recovery.

Abstract
Mesial frontal and temporoparietal brain areas differ in activity between high and low dream recallers, and lesion studies have found cessation of dreaming in patients with damage to these areas. This study extends these findings by assessing the relationship of dream cessation, and dream and nightmare frequencies, to severity of injury in patients at a head trauma clinic. 52 participants (M = 36, F = 16; mean age = 39.69, SD = 13.72) completed a questionnaire assessing frequency of dreams, nightmares and night terrors, tests for depression and anxiety, and a neuropsychological examination and test battery. 34.6 % of patients reported that they do not dream, which is comparable to Solms' (1997) finding of 34.9 % in his brain injury sample. This contrasts with the rate of not reporting dreams in the general population of 6.1-7.1 %. Dream cessation participants had significantly greater severity of brain injury as measured by the Glasgow Coma Scale and post traumatic amnesia, but cessation was not related to neuropsychological scores. Compared to the general population there was a higher prevalence of weekly nightmares (13.5 %) and also of reporting never having nightmares (48.1 %), the former predicted by anxiety, the latter by brain injury severity. The data cannot distinguish between whether brain injury is halting the production of dreams or causes failure to encode and recall dreams on waking. Future studies using within-sleep behavioral or imaging methods may distinguish between these possibilities. Future studies should also determine if recovery of dream experience is predictive of more global recovery from brain injury.