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Show ,. Clin, Neuro-l'phth.l/nHl/. 2: 3--t, 1'182. The Aged Brain The c('ntr.ll nerVl)US svstem .l~es in .1 prl'did,lble f.tshil)(1 in Illl'St ,1dults; .1t 30 Vl'.lrS, the Ill'rm.ll br,lin h.1s its m,l,imum wl'i~hl.·which is rl'dun'd by 150 ~ by (>5 ye.lrs.l. c' Sli~ht ventricul.lr dil.lt.1til)1l with neuflln,ll It)SS .1I1d pwminent lipllfuscill is l)bserved. The Llter.11 ventricles .lre v.lri.1blv ellLlrged l)ll .1 Ill)lll'bstrudivl' b.lSis in indivi·du.1Is lwer (>0 ve.lrs. but some h,1\'e nl)rmJ.I ventricles without ~erebr.ll .1trophv." Atwphy d the br.lin which increJ.ses with .1ge is m.lnifested by dilated IJ.ter.l1 ventrides, ll.lrwwed gyri with 'widened sulci. l)r .1 combin.ltion of these features. It seems patholt)gic. but may represent the aging process. Individuals (>0 yeMs l)r llider with severe cerebral atrophv have dementia, usually without significant large vessel disease. Nevertheless, amyloid deposits in blood vessels increase after the sixth decade." Changes in the cerebrospinal fluid flow pathways in the elderlv include fibrosis in the choroid plexus associated with calcific deposits. These can be so intense that the choroid plexus can be visualized on a plain skull x-ray. Focal ependymal cell loss is seen along the lateral, third, and fourth ventricles, and fibrotic thickening of the Pacchionian granulations is evident, particularly around the superior sagittal sinus.' These findings are often associated with lateral ventriculomegaly. Many of these people expire with minimal morphologic findings, including dilated lateral nonobstructive ventricles and mild aspiration-type bronchopneumonia," This pneumonia in the elderly is related to defects in humoral and cellular immunity and increased oropharyngeal colonization by gram negative bacilli."" >; These microbes can be aspirated due to decreased gag reflexes producing bacterial pneumonia with terminal sepsis. c,, 7 Dementing diseases of the central nervous system are considered either as nontreatable dementias typified mainly by senile dementia of the Alzheimer's type, or treatable dementias. The former accounts for 55% of all dementing diseases, and the latter 45%"'!' About 30% of the treatable dementias are reversible and the remaining 70% irreversible, but nonprogressive. Causes of dementia in 415 patientsY included Alzheimer's disease in 45% followed by alcoholic dementia (15%), multiinfarct dementia (10%), and pseudodementias (10%) (e.g., depressions, schizophrenia, mania, and hysteria). Other infrequent causes of treatable dementia are the so-called "normal pressure hydrocephalus," intracranial masses, Huntington's cho- March 1982 Editorial re.1, drug tl)xicity, posttraumatic dementia, endocrine disturb.lnces, infections, and metabolic dise. 1ses. Alzheimer's diseJ.se, the most significant dementing diseJ.se, is .I major cause of morbidity and mortJ.lity in individuals bO years and older. It is the fourth most common cause of death in the United States, predisposing the host to aspiration bronchopneumonia." Morphologic changes of presenile J.nd senile Alzheimer's disease are atrophy of the brain with widened sulci and enlarged lateral ventricles. This latter feature appears most significanl.'" c,, 1" Microscopically, cerebral cortical neurons are lost, particularly in layers 3 and 5, and are associated with argyrophilic neuritic (senile) plaques, neurofibrillary tangles, and granulovacuolar degeneration. The most significant gross feature of Alzheimer's disease is nonobstructive dilatation of both lateral ventricles, which may not be seen in all patients." c" '" Histologically, the disease is characterized by neurofibrillary tangles and neuritic plaques in the cortex which can be demonstrated by silver preparations (Bodian stain). Neurofibrillary tangles are twisted, fused neurotubules and neurofilaments within neurons; whereas, neuritic plaques are degenerated synapses often with central amyloid cores. 1 I Increased neuritic plaques are seen most commonly in idiopathically demented patients, and their presence portends some degree of Alzheimer's senile dementia that histomorphologically is identical to presenile dementia or classic Alzheimer's disease.l~ GranulovJ.cuolar changes Me confined to hippoc.1mpal neurons. With age, an increase in neuritic plaques. neuwfibrill, lry tangles, .llld granulov.lCuolM changes lKcurs. I:', il In first degree relatives d p.ltients with Alzheimer's disease, Down's syndrome .llld Iymphoproliferative diseases appear with increased frequency.iC. At the University of Mi.1mi-J,lCksl1/l Memoridl MedicJ.I Center, 35 control p,ltients were comp.lred with 38 .lge- .llld se:>'-nldtched p.1tients with Alzheimer's dise.1se whl) h.1d five llr more neuritic plaques per lOOX field. The Il1l)St common cause of death in patients with Alzheimer's disease was sepsis due to pneunloniJ., which was less frequent in the control group. This latter group expired most frequently from arteriosclerotic heart disease. Cancer occurred similJ.r1y in both groups. A unique syndrome, known as "normal pressure hydron:phalus:'!1;· 17 is manifested by the triad of dementid, unsteady gait, and urinary incontinence. 3 Edih'ri.ll: The Aged Hr.lin The dis(lrder m.1Y be idiopathic, but h.ls been associ.1ted with other disorders such as head tr.lUm.1. R.1diologic.llly, dilated 1.1ter.11 ventricles shl1w retention for more th.m 24 hours of an isotope such .IS .m indium-III by scinticisternographv Ther.lpeutic.llly, individu.1ls with "normalpressure hydwceph.1Ius" dell10nstr.1te clinical impnwen1l'nt (If their denH'nti.1 following extrdcranial ventricul.u shunting. Nonobstructive ventriculdr enl.ugement, however, may be .1Ssocidted with .Iging, .IS well .1S prim.lry degenerdtive diseases like Alzheimer's dise.lse, Pick's disedse, ,md hereditary idiop.1thic cerebr,ll .1trophies; second,uy degener,1tive disc>rders due to trauma, infections, toxicmetdbolic disorders, dnd vdscular disease, chronic schizophrenia, pneumoencephalography, and electric shock therapy. Using autopsy material from the University of Miami-Jackson Memorial Medical Center, the lateral, third and fourth ventricles were measured volumetrically. Seventeen study patients, with a mean lateral ventricular volume of 38 ml, were compared with 15 control age- and sex-matched patients with a mean lateral ventricular volume of 21 mI.' Although none of the controls had dementia, five (29%) of the study patients were so encumbered. No other neurological defects were evident in either group. Cerebral atrophy was seen with the same frequency in both groups and was not correlated with atherosclerosis. Moderate atherosclerosis with focal subocclusive changes was seen four times as frequently in the study group as in the control group. Mild to severe Alzheimer's senile changes were found more frequently in the study than in the control patients. The aging brain gradually increases its ventricular size from the fifth through the seventh decade, which appears more evident in the eighth and ninth decades,'K and has been associated with reduced cerebration. I~ About 60% of patients over 60 years have a moderate or severe ventricular enlargement as demonstrated on computed axial tomography. 2l1 Once either reversible or irreversible treatable causes of dementia have been excluded, any patient without a specific cause for his dementia should be considered to hdve Alzheimer's disease. Joseph c. Parker Jr., M.D. The University of Tennessee Knoxville, Tennessee 37020 References E.lrnest, M.R., He.lton, RK., Will..inslln, WE.. .md M.mke, W.F.: Cortic.11 .Itrl'phv, ventricui.lr enl.Hgl'ment .md intellec!u,11 imp.lirment in the .Iged. Ncur" l"gy 29: I 131'1- I 143, 1<)7<l 2. Cor'clli" IAN.· Aging .Ind the dementi.ls. In (;r('('I1li.. ld\ Ne[Jf(,,,.Jth,,l,,gv (3rd ed.). W. BIJcl..wol)d .md j.A.N. Corsellis, Eds. London, 1976, pp. 796-817. 3. Parker, j.C, jr., Reyes, P.F., and Hess, j.R.: Interpreting post-mortem non-obstructive hydrocephalus in the elderly. (Abstract.) Lab. Invest. 42: 141, 1980. 4 Lee, 5.-5. and 5temmermann, G.N.: Congophd,c Jngiopathy .1I1d cerebral hemorrhage. Arch. PathoJ. Lab. Med. 102: 317-321,1978. 5. Parker, j.C, jr.: The old age syndrome: Subtle cerebral degeneration and bronchopneumonia. Geriatrics 27 4: 94-98, 1972. 6 Dorff, G.I., Rytel, M.W., Farmer, 5.G., and Scanlon, G.: Etiologies and ch.uacteristic features of pneumanias in a muncipal hospital. 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