Mohammed T. Abou-Saleh

EARLY-ONSET DEMENTIAS 275(a) Sleep disorders, including sleep apnea and narcolepsy.(b) Depression, PTSD, anxiety disorders.(c) Ongoing occult substance abuse.(d) Subacute delirium.5. Review medications:(a) Long-term anticholinergic, neuroleptic and/or anticonvulsantuse is associated with cognitive impairment.(b) Overaggressive treatment of hypertension can result inhypoxic/ischemic encephalopathy.6. Family history:(a) Strokes or MI at an early age suggests coagulopathy orfamilial hypercholesterolemia.(b) Strong family history of diabetes mellitus should promptsearch for occult diabetes.(c) Early-onset dementia without other neurological findingssuggests familial EOAD.(d) Amyotrophic lateral sclerosis has a familial associationwith frontotemporal dementia.7. Mental status examination is intended to reveal the pattern ofcognitive impairment and should minimally include:(a) Mini-Mental Status Examination.(b) Additional tests for retrieval, such as list generation.(c) Additional tests for attention, such as asking to recitemonths in reverse.(d) Additional tests for visuospatial function, such as drawinga transparent cube.(e) Tests of motor praxis, such as demonstrating untying andtying a shoelace.(f) Tests of frontal lobe function, such as Luria sequencing,visual go–no go testing and general assessment ofjudgment.8. Thorough neurological examination:(a) See Table 50c.2.9. Head imaging:(a) Some form of head imaging should probably be performedin all cases of early-onset dementia, especially if focalneurological findings are present.(i) While CT is readily available and inexpensive, MRI issuperior in imaging the posterior fossa and indistinguishing between demyelination and edema inwhite matter lesions.10. Laboratory studies:(a) Should be tailored to the findings on history, mental statusand physical examinations.(i) The interested reader is referred to an excellent andexhaustive review of rare dementia syndromes byReichmann and Cummings 11 .(b) All patients should be tested for blood count, electrolytes,liver panel, albumin, B 12 , folate, VDRL, sedimentationrate.(i) While the yield of these investagations is low, theircost is low as well, and they screen for reversiblecauses of dementia.(c) ApoE genotype is reasonable in cases suspicious forEOAD, especially if there is no significant familyhistory.REFERENCES1. Liston E. The clinical epidemiology of presenile dementia. J NervMent Dis 1979; 167: 329–36.2. Liston E. Clinical findings in presenile dementia. J Nerv Ment Dis1979; 167: 337–42.3. McGonigal G, Thomas B, McQuade C et al. Epidemiology ofAlzheimer’s presenile dementia in Scotland, 1974–88. Br Med J 1993;306: 680–3.4. Newens AJ, Forster DP, Kay DW et al. Clinically diagnosed preseniledementia of the Alzheimer type in the Northern Health Region:ascertainment, prevalence incidence and survival. Psychol Med 1993;23: 631–44.5. Treves T, Dorczyn AD, Zilber N et al. Presenile dementia in Israel.Arch Neurol 1986; 43: 26–9.6. Woodburn K, Johnstone E. Measuring the decline of a population ofpeople with early-onset dementia in Lothian, Scotland. Int J GeriatPsychiat 1999; 14: 355–61.7. Woodburn K, Johnstone E. Ascertainment of a population of peoplewith early-onset dementia in Lothian, Scotland. Int J Geriat Psychiat1999; 14: 362–7.8. Jacobs D, Sano M, Marder K et al. Age at onset of Alzheimer’sdisease: relation to pattern of cognitive dysfunction and rate ofdecline. Neurology 1994; 44: 1215–20.9. Martin J, ed. Scientific American Molecular Neurology. New York,NY: Scientific American, 1998.10. Sadovnick AD, Tuokko DA, Applegarth JR et al. The differentialdiagnosis of adult-onset metachromatic leukodystrophy and earlyonsetfamilial Alzheimer disease in an Alzheimer clinic population.Can J Neurol Sci 1993; 20: 312–18.11. Reichman W, Cummings JL. Diagnosis of rare dementia syndromes:an algorithmic approach. J Geriat Psychiat Neurol 1990; 3: 73–83.12. Gersing K, Doraiswamy PM, Krishnan KR et al. Vascular dementia.Curr Opin Psychiat 1998; 11: 425–9.13. Doraiswamy PM, Steffens DS, Tabrizi S, Pitchumoni S. Earlyrecognition of Alzheimer’s disease. J Clin Psychiat 1998; 59(s13):6–18.