Sex, Love, and the Brain
ABSTRACTS & COMMENTARY
Sources: Lane RJM. Recurrent coital amnesia. J Neurol Neurosurg Psychiatry 1997;260 (letter); Farnham FR, et al. Pathology of love. Lancet 1997;350:710.
Two case reports from the british medical literature illustrate the sometimes bizarre relationships between cerebral pathology and human sexual behavior. Russell Lane from Charing Cross Hospital in London described a 64-year-old man who, on five separate occasions over an eight-year period, had attacks of amnesia after sexual intercourse. He exhibited characteristic features of transient global amnesia (TGA) including repetitive questioning of events, but not of place or person. Although his memory returned within 30-60 minutes, he remained amnesic for the period of intercourse and had "only a very hazy recollection of foreplay." His past history was significant for migraine without aura over the past 20 years and multiple episodes of post-climax occipital headache during intercourse. There were no other circumstances in which he developed amnesia, and no neurologic problems complicated intercourse on numerous other occasions. Neurologic examination and brain imaging were normal; however, his EEG showed sharply contoured theta activity in the right frontal temporal area.
Farnham and colleagues reported a 20-year-old man who had been incarcerated for stalking a 28-year-old female neighbor and breaking in to her apartment with the false belief that she was his fiancee and that they were to live together. He had a past history of seizures which are not well-described in this report but were presumed to be of temporal lobe origin. He experienced déjà vu, symptoms of derealization, depersonalization, and thought implantation in addition to his erotomaniac delusion. Neuropsychological testing revealed impairment of verbal memory and that he possessed little insight into his illness. He was treated initially with haloperidol, which resulted in an increase in seizure frequency and a worsening of his psychosis. Subsequently, he underwent an MRI of the brain that revealed a large anteriorvenous malformation in his left frontal lobe pressing on the anterior pole of the left temporal lobe. He was more vigorously treated with antiepileptic medication with resolution of his psychotic symptoms. He then underwent embolization of the AVM. He had remission of seizures as well as his psychotic symptoms and exhibited no further episodes of stalking in the subsequent year.
Intense physical exertion is one of the known precipitants of transient global amnesia (TGA), and it is not unprecedented for an individual to present with amnesia with onset coincident with sexual intercourse. TGA is a syndrome of impaired short-term memory often associated with retrograde amnesia and repetitive questioning occurring in a context of an otherwise non-focal neurologic examination. The events by definition must last less than 24 hours and typically show a maximum during the first 1-2 hours. The causes of TGA are uncertain, although various electroencephalographic and functional brain imaging studies have suggested that decreased perfusion of either the medial temporal lobes bilaterally or the midline thalamic nuclei can give rise to the syndrome. Although the condition is usually benign and idiopathic, variants include a similar amnestic syndrome of epileptic origin as well as other structural and even iatrogenic causes. TGA usually occurs as a single episode; however, recurrences are well-documented. Multiple episodes and atypical features should instigate an evaluation for precipitating causes.
Erotomaniac delusions are often reported in the psychiatric literature, but few, if any, cases have been documented to arise from discrete intracerebral pathology. The occurrence of a seizure disorder exacerbated by neuroleptic treatment and associated with a profound verbal memory impairment led appropriately to performance of a brain imaging study in this patient. Had that action not been taken, he might otherwise have been incarcerated indefinitely and/or incapacitated by both his seizure disorder and psychosis. As the authors comment: "public anger at intrusive forms of antisocial behavior should not blind clinicians to the possibility of underlying organic pathology." It is also the case that antisocial behavior is only rarely the direct consequence of brain pathology and that cases such as this must be viewed as the exception rather than the rule. nrr