Blog #164: MEMORY: SUBJECTIVE COMPLAINTS VS ACTUAL OBJECTIVE DEFICITS IN EPILEPSY
Who amongst us doesn’t find faultwith our own memory? But are memory concerns and complaints due to actual brainpathology or are they within the normal age-spectrum? Over half of patientswith epilepsy complain of impaired memory. Are they actual memory deficits,though? We know that anticonvulsant medications commonly have deleteriouseffects on memory as can depression, other medications and illnesses.
Exploring memory researchersrecruited patients with Temporal Lobe Epilepsy (TLE).1 TLE diagnosiswas based on abnormal EEG and clinically typical seizures. Our temporal lobes arewhere memory is generated and preserved. Damage there does affect memorywhereas damage to other parts of the brain does not have as serious effects onmemory. Generalized epilepsy, which does not focus on temporal lobes, seems tohave less deleterious effects on memory as compared with TLE.
Researchers recruited 47 patientswith TLE. Age and sex-matched 35 healthy controls were similarly studied.Self-evaluation memory questionnaires were used to assess the magnitude ofmemory complaints. All were then studied with neuropsychological examinations.A surprise recall testing 3 weeks later occurred. No significant differences onstandard testing were found between the performance of patients and controls.
The two groups were then brought backthree weeks later. The surprise recall tests 3 weeks later revealed significantdifferences between the two groups. They were assessed if they recalled simpleevents that occurred during that original testing 3 weeks before. For example,was there a memory of a water glass being offered? Did the examinerleave the room and change what they wore? Did the subject recall the phoneringing twice during the visit, or recall being asked to retrieve aquestionnaire from a shelf, etc.? In the absence of spontaneous recall withoutcues, cues were then provided by the researchers followed by recognitionquestions such as “did the phone ring once or twice? Were you offered wateretc.? Scores were generated.
The standard neuropsychological battery wehave relied on to test cognition and memory has some blind spots; an adequateassessment of autobiographical memory and our “long term” memory assessmentsoccur 10 to 30 minutes after the information is encoded. Traditionally thesetests haven’t been performed. It is these blind spots that have been addressedin this study. People with subjective memory complaints that were corroboratedby family members had normal performance on standard neuropsychological testing.But scores 3 weeks later were significantly lower in the epilepsy group.
This information is another reminder that we need to listen closely toour patients’ complaints, and that our gold standards need to be updated as ourunderstanding of memory evolves.
1) Lemesle B, Barbeau EJ, Milongo Rigal E, et al.Hidden objective memory deficits behind subjective memory complaints inpatients with temporal lobe epilepsy. Neurology. 2022;98(8): E818-E828
LanceFogan, M.D. is Clinical Professor of Neurology at the David Geffen School ofMedicine at UCLA. His hard-hitting emotional family medical drama, “DINGS, is told from a mother’s point of view.“DINGS” is his first novel. Aside from acclamation on internet bookstoresites, U.S. Report of Books, and the Hollywood Book Review, DINGS has beenadvertised in recent New York Times Book Reviews, the Los Angeles TimesCalendar section and Publishers Weekly. DINGS teaches epilepsy and is now available in eBook, audiobook, soft and hard covereditions.
