2-minute Consultation: Dementia: Many Facets, No Cure

Ms. Wick is a senior clinical researchpharmacist at the National CancerInstitute, National Institutes of Health,Bethesda, Maryland. The viewsexpressed are those of the author andnot those of any government agency.

Mention dementia these days,and you are as likely to heara memory joke as you are tosee a fleeting look of fear. Four dementiasare common: Alzheimer's disease(AD; now affecting approximately 4.5million Americans^1-5), vascular dementia(VaD), dementia with Lewy bodies(DLB), and frontotemporal dementia(FD).⁶ Irreversible and incurable, dementiacan be almost impossible to categorizeuntil autopsy; yet, earlier diagnosisis associated with better prognosis.^7-9

Some memory loss is normal. Age-associatedCognitive Impairment (AACI)(or, benign memory impairment) occursin up to 39% of elders¹⁰; experiencesinclude tip-of-the-tongue events(word-finding failures), slower learningor concentration, and mild forgetfulness.¹¹ AACI patients navigate dailyactivities satisfactorily, at times jokingabout their deficits.^6,12,13

Alzheimer's Dementia

AD progresses slowly. Patients oftenare aware of faltering short-term memoryand hide it until later stages of AD.AD patients do not learn, and promptingis useless. Eventually, disorganizedthinking and often psychotic mood andpersonality disorders incapacitate patients.¹ Most AD patients live <8 yearsafter diagnosis; comorbidities shortensurvival.¹⁴

Vascular Dementia

Once called multi-infarct dementia,VaD's risk factors include hypertension,diabetes, arterial disease, andsmoking.^15-17 VaD patients are acutelyaware of their deficits and learn, butthey may recall material only afterhints. VaD impairment plateaus untilanother cerebral accident. Gait disorders,depression, apathy, and moodand behavioral changes are common.^15,18-20 To prevent VaD, cliniciansuse antiplatelet therapy, control hypertension,and address risk factors.²⁰

Frontotemporal Dementia

FD (or, Pick's disease) causes behavioralchanges and language problemsin adults aged 35 to 75.^21,22 Disinhibitedand socially inappropriate, FD patientsoften lack empathy and develop poorhygiene.²¹ Compulsive behaviors canbe self-destructive (eg, exiting a movingvehicle) or criminal (eg, theft), readingand writing skills erode, and somepatients become mute in as little as 2years.²³ FD is untreatable; therefore,management targets agitation andbehavior.²¹

Dementia with Lewy Bodies

Fifteen percent to 25% of dementiapatients have DLB²⁴; severe dopaminergicloss causes bradykinesia, difficultyexecuting fine motor skills, maskedface, stooped posture, and shufflingthat looks like Parkinson's disease (PD)but less severe.²⁵ Because DLB's symptomsfluctuate widely hourly and daily,others may suspect that DLB patientsare "faking it."

Vivid (but not frightening) visual hallucinationsoften occur during seriousconfusion.²⁶ Capgras syndrome—believinga significant other is an imposter—is common, as well as apathy,depression, slowed thought processes,getting lost easily, insomnia, autonomicdysfunction, and losing one'sthought midsentence.²⁵ In almost halfof DLB patients, neuroleptic exposureworsens the PD-like symptoms, increasescognitive deficits and hallucinations,and can cause life-threateningneuroleptic malignant syndrome.^26-28

Conclusion

Between 20% and 50% of dementiapatients have mixed dementias.^16,29Clinicians treat mixed-dementia patientsempirically. Currently, severaldrugs are available to treat dementia;none are curative or more than satisfactoryin their effects. Most patientswith dementia end life in an institution.Perhaps this will not always be thecase.

Table

References

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• Shafto MA, Burke DM, Stamatakis EA, Tam PP, Tyler LK. On the Tip-of-the-Tongue: Neural Correlates of Increased Word-finding Failures in Normal Aging. J Cogn Neurosci. 2007; [Epub ahead of print].
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• Nagata K, Maruya H, Yuya H, et al. Can PET data differentiate Alzheimer's disease from vascular dementia? Ann N Y Acad Sci. 2000;903:252-261.
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• University of California, San Francisco Memory and Aging Center. Frontotemporal dementia (FTD). memory.ucsf.edu/Education/Disease/ftd.html. Accessed November 6, 2007.
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