Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-24T05:51:23.289Z Has data issue: false hasContentIssue false
  • English
  • Français

I think, therefore I forget – using experimental simulation of dementia to understand functional cognitive disorders

Published online by Cambridge University Press:  30 September 2019

Laura McWhirter Open the ORCID record for Laura McWhirter [Opens in a new window] ,
Brendan Sargent ,
Craig Ritchie ,
Jon Stone  and
Alan Carson
Laura McWhirter*
Affiliation:
Centre for Clinical Brain Sciences, The University of Edinburgh Kennedy Tower, University of Edinburgh Royal Edinburgh Hospital, Edinburgh, United Kingdom
Brendan Sargent
Affiliation:
Centre for Clinical Brain Sciences, The University of Edinburgh Kennedy Tower, University of Edinburgh Royal Edinburgh Hospital, Edinburgh, United Kingdom
Craig Ritchie
Affiliation:
Centre for Clinical Brain Sciences, The University of Edinburgh Kennedy Tower, University of Edinburgh Royal Edinburgh Hospital, Edinburgh, United Kingdom
Jon Stone
Affiliation:
Centre for Clinical Brain Sciences, The University of Edinburgh Kennedy Tower, University of Edinburgh Royal Edinburgh Hospital, Edinburgh, United Kingdom
Alan Carson
Affiliation:
Centre for Clinical Brain Sciences, The University of Edinburgh Kennedy Tower, University of Edinburgh Royal Edinburgh Hospital, Edinburgh, United Kingdom
*
*Laura McWhirter, Email: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Background.

Symptoms of functional neurological disorder have traditionally been thought to depend, in part, on patients’ ideas about symptoms rather than on the rules of pathophysiology. The possibility that functional cognitive symptoms might similarly reflect ideas of dementia has not been explored. We aimed to assess beliefs, through performance, about symptoms of dementia in healthy non-medical adults with the intention of identifying potential markers of functional cognitive disorders.

Methods.

Healthy volunteers were asked to simulate symptoms of mild dementia during testing with the Montreal Cognitive Assessment (MoCA), coin-in-hand forced-choice test, short digit span trials, Luria 3-step test and interlocking finger test. Family history of dementia was recorded.

Results.

In 50 participants aged 18–27, simulating dementia, mean MoCA score was 16 (SD 5.5, range 5–26). Delayed recall was the most frequently failed item (100%) and cube drawing least frequently failed (42%). Twenty-six percent failed forward three-digit span and 36% failed reverse two-digit span. On the coin-in-hand test, 32% scored at or below chance level. Inconsistent response patterns were common.

Conclusions.

Cognitively healthy young adults simulating mild dementia perform similarly to older adults with mild dementia, demonstrating beliefs that dementia is associated with significant global impairment, including attention, motor function, and letter vigilance, but preservation of cube drawing. Inconsistent response patterns were common. Contrary to expectation, family history of dementia did not influence performance. Two and three digit span showed particular promise as a bedside test for simulation. Further investigation will establish whether similar patterns of results are produced in individuals with functional cognitive symptoms.

Keywords

Dementiadiagnosisfunctional cognitive disorderfunctional neurological disordersimulation.
Type
Original Research
Information
CNS Spectrums , Volume 25 , Issue 4 , August 2020 , pp. 511 - 518
Copyright
© Cambridge University Press 2019

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Sierra-Rio , A, Balasa, M, Olives, J, et al.Cerebrospinal fluid biomarkers predict clinical evolution in patients with subjective cognitive decline and mild cognitive impairment. Neurodegener Dis. 2016; 16(1-2): 69–76. doi:10.1159/000439258Google Scholar
Handels, RLH, Joore, MA, Vos, SJB, et al.Added prognostic value of cerebrospinal fluid biomarkers in predicting decline in memory clinic patients in a prospective cohort. J Alzheimer’s Dis. 2016; 52(3): 875–885. doi:http://dx.doi.org/10.3233/JAD-151120Google Scholar
Hessen, E, Eckerstrom, M, Nordlund, A, et al.Subjective cognitive impairment is a predominantly benign condition in memory clinic patients followed for 6 years: the Gothenburg-oslo MCI Study. Dement Geriatr Cogn Dis Extra. 2017; 7(1): 1–14. doi:http://dx.doi.org/10.1159/000454676Google Scholar
Mitchell, AJ. Is it time to separate subjective cognitive complaints from the diagnosis of mild cognitive impairment? Age Ageing. 2008; 37(5): 497–499. doi:https://dx.doi.org/10.1093/ageing/afn147Google Scholar
Mitchell, AJ, Shiri-Feshki , M. Rate of progression of mild cognitive impairment to dementia - Meta-analysis of 41 robust inception cohort studies. Acta Psychiatr Scand. 2009; 119(4): 252–265. doi:10.1111/j.1600-0447.2008.01326.xGoogle Scholar
Stone, J, Pal, S, Blackburn, D, Reuber, M, Thekkumpurath, P, Carson, A. Functional (psychogenic) cognitive disorders: a perspective from the neurology clinic. J Alzheimer’s Dis. 2015; 48(S1): S5–S17.Google Scholar
Blackburn, DJ, Wakefield, S, Shanks, MF, Harkness, K, Reuber, M, Venneri, A. Memory difficulties are not always a sign of incipient dementia: a review of the possible causes of loss of memory efficiency. Br Med Bull. 2014; 112(1): 71–81. doi:10.1093/bmb/ldu029Google Scholar
Teodoro, T, Edwards, MJ, Isaacs, JD. A unifying theory for cognitive abnormalities in functional neurological disorders, fibromyalgia and chronic fatigue syndrome: systematic review. J Neurol Neurosurg Psychiatry. 2018; 89(12): 1308–1319. doi:10.1136/jnnp-2017-317823Google Scholar
Stone, J, Mutch, J, Giannokous, D, Hoeritzauer, I, Carson, A. Hurst revisited: are symptoms and signs of functional motor and sensory disorders “dependent on idea”? J Neurol Sci. 2017; 381(August ): 188–191. doi:10.1016/j.jns.2017.08.3248Google Scholar
Nasreddine, ZS, Phillips, NA, Bedirian, V, et al.The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment. J Am Geriatr Soc. 2005; 53(4): 695–699. doi:10.1111/j.1532-5415.2005.53221.xGoogle Scholar
Moo, LR, Slotnick, SD, Tesoro, MA, Zee, DS, Hart, J. Interlocking finger test: a bedside screen for parietal lobe dysfunction. J Neurol Neurosurg Psychiatry. 2003; 74(4): 530–532. doi:10.1136/JNNP.74.4.530Google Scholar
Elamin , M, Bennett, G, Symonds, A, et al.Introducing a brief screening a tool for motor signs in patients with dementia. Neurology. 2015; 84(Suppl. 14) P6.203.Google Scholar
Bak, TH. Why patients with dementia need a motor examination. J Neurol Neurosurg Psychiatry. 2016; 87(11): 1157.Google Scholar
Ahmed, S, Baker, I, Thompson, S. Utility of testing for apraxia and associated features in dementia. J Neurol Neurosurg Psychiatry. 2016; 87:1158–1162. doi:10.1136/Google Scholar
Kapur, N. The coin-in-the-hand test: a new “bed-side” test for the detection of malingering in patients with suspected memory disorder. J Neurol Neurosurg Psychiatry. 1994; 57(3): 385–386. doi:10.1136/JNNP.57.3.385Google Scholar
Edwards, MJ, Adams, RA, Brown, H, Parees, I, Friston, KJ. A Bayesian account of “hysteria.” Brain. 2012; 135(11): 3495–3512. doi:10.1093/brain/aws129Google Scholar
den Bergh O, Van, Witthöft, M, Petersen, S, Brown, RJ. Symptoms and the body: taking the inferential leap. Neuoscience Biobehav Rev. 2017; 74:185–203. doi:10.1016/j.neubiorev.2017.01.015Google Scholar
Hurst, AF. The Psychology of the Special Senses and Their Functional Disorders. 1st ed. London: Frowde, Hodder & Stoughton; 1920. http://books.google.co.uk/books?id=vOZTQwAACAAJ&dq=hurst+croonian+lectures&hl=&cd=1&source=gbs_api.Google Scholar
Rossetti, HC, Lacritz, LH, Hynan, LS, Cullum, CM, Van Wright, A, Weiner, MF. Montreal Cognitive Assessment performance among community-dwelling African Americans. Arch Clin Neuropsychol. 2017; 32(2): 238–244. doi:http://dx.doi.org/10.1093/arclin/acw095Google Scholar
Malek-Ahmadi , M, Powell, JJ, Belden, CM, Evans, L, Coon, DW, Nieri, W. Age-and education-adjusted normative data for the Montreal Cognitive Assessment (MoCA) in older adults age 70-99. Aging, Neuropsychol Cogn. 2015; 22(6): 755–761. doi:10.1080/13825585.2015.1041449Google Scholar
Borland, E, Nägga, K, Nilsson, PM, Minthon, L, Nilsson, ED, Palmqvist, S. The Montreal Cognitive Assessment: normative data from a large Swedish population-based cohort. J Alzheimer’s Dis. 2017; 59(3): 893–901. doi:10.3233/JAD-170203Google Scholar
Julayanont, P, Phillips, N, Chertkow, H, Nasreddine, ZS. Montreal Cognitive Assessment (MoCA): concept and clinical review. In: Larner, AJ, ed. Cognitive Screening Instruments: A Practical Approach. London: Springer; 2017:139–195. doi:http://dx.doi.org/10.1007/978-1-4471-2452-8_6Google Scholar
Anderson, EW, Trethowan, WH, Kenna, JC. An experimental investigation of simulation and pseudo-dementia . Acta Psychiatr Scand Suppl. 1959; 34(132): 1–42.Google Scholar
Haines, ME, Norris, MP. Comparing student and patient simulated malingerers performance on standard neuropsychological measures to detect feigned cognitive deficits. Clin Neuropsychol. 2001; 15(2): 171–182. doi:10.1076/clin.15.2.171.1891Google Scholar
Wilson, RS, Sytsma, J, Barnes, LL, Boyle, PA. Anosognosia in dementia. Curr Neurol Neurosci Rep. 2016; 16(9): 77. doi:10.1007/s11910-016-0684-zGoogle Scholar
Rossetti, HC, Lacritz, LH, Cullum, CM, Weiner, MF. Normative data for the Montreal Cognitive Assessment (MoCA) in a population-based sample. Neurology. 2011; 77(13): 1272–1275. doi:10.1212/WNL.0b013e318230208aGoogle Scholar
Rudman, N, Oyebode, JR, Jones, CA, Bentham, P. An investigation into the validity of effort tests in a working age dementia population. Aging Ment Health. 2011; 15(1): 47–57. doi:10.1080/13607863.2010.508770Google Scholar
Iverson, GL, Tulsky, DS. Detecting malingering on the WAIS-III: Unusual Digit Span performance patterns in the normal population and in clinical groups. Arch Clin Neuropsychol. 2003; 18(1): 1–9. doi:10.1016/S0887-6177(01)00176-7Google Scholar
Carlesimo, G, Fadd, L, Lorusso, S, Caltagirone, C. Verbal and spatial memory spans in Alzheimer’s and multi-infarct dementia. Acta Neurol Scand. 1994; 89:132–138.Google Scholar
Butters, N, Cermak, LS. Alcoholic Korsakoff’s Syndrome : An Information-Processing Approach to Amnesia. New York: Academic Press; 1980.Google Scholar
Greiffenstein, MF, Baker, WJ, Gola, T. Validation of malingered amnesia measures with a large clinical sample. Psychol Assess. 1994; 6(3): 218–224. doi:10.1037/1040-3590.6.3.218Google Scholar
Mathias, CW, Greve, KW, Bianchini, KJ, Houston, RJ, Crouch, JA. Dysfunction using the reliable digit span in traumatic brain injury. Assessment. 2002; 9(3): 301–308. doi:10.1177/1073191102009003009Google Scholar
Larrabee, GJ. Detection of malingering using atypical performance patterns on standard neuropsychological tests. Clin Neuropsychol. 2003; 17(3): 410–425. doi:10.1076/clin.17.3.410.18089Google Scholar
Bharambe, V, Larner, AJ. Functional cognitive disorders: demographic and clinical features contribute to a positive diagnosis. Neurodegener Dis Manag. 2018; 8(6): 377–383.Google Scholar
Larner, AJ. Screening utility of the “attended alone” sign for subjective memory impairment. Alzheimer Dis Assoc Disord. 2014; 28(4): 364–365. doi:https://dx.doi.org/10.1097/WAD.0b013e3182769b4fGoogle Scholar
Williamson, J, Larner, A. Attended with and head-turning sign can be clinical markers of cognitive impairment in older adults. Int Psychogeriatrics. 2018; 20(10): 1569–1569. doi:10.1017/S1041610218000121Google Scholar
Reuber, M, Blackburn, DJ, Elsey, C, et al.An Interactional Profile to Assist the Differential Diagnosis of Neurodegenerative and Functional Memory Disorders. Alzheimer Dis Assoc Disord. 2018; 32(3): 197–206. doi:10.1097/WAD.0000000000000231Google Scholar
Bailey, C, Poole, N, Blackburn, DJ. Identifying patterns of communication in patients attending memory clinics: a systematic review of observations and signs with potential diagnostic utility. Br J Gen Pract. 2018; 68(667): e123–e138. doi:10.3399/bjgp18X694601Google Scholar
Jones, D, Drew, P, Elsey, C, et al.Conversational assessment in memory clinic encounters: interactional profiling for differentiating dementia from functional memory disorders. Aging Ment Health. 2016; 20(5): 500–509. doi:https://dx.doi.org/10.1080/13607863.2015.1021753Google Scholar