Corpora Amylaecia Deposition In The Olfactory Bulb And Tract In Ageing And Alzheimer’s Disease

ABSTRACT

Background: The olfactory system has several interesting anatomical and physiological features althougholfaction has remained a ‘neglected sense’. Olfactory functioning is a valid indicator of the ageing brain sopresent study was designed to investigate the age of appearance of corpora amylaecia in the olfactory bulb andtract and compare with well known cases of Alzheimer’s disease.Aims of the study To detect deposition of corpora amylaecia in the human olfactory bulb and tract in differentage groups and Alzheimer’s disease.Materials and Methods: 22 brain specimens were collected from cadavers from Anatomy department of MGMMedical College, Navi Mumbai and from National Institute of Mental Health and Sciences (NIMHANS), Bangalore.The study was carried out in 20 undemented specimen, divided into four groups (5 samples in each) according toage group I (20-39yrs), group II(40-59yrs),group III (60-79yrs),group IV(80 yrs and above) and 2 specimen ofAlzheimer’s disease as a control group. Histological evaluation was done with Haematoxylin and Eosin stain,Luxol fast blue stain and Immunohistological stain, Glial fibrillary acidic protein (GFAP) antibody to studycorpora amylaecia. Statistical analysis was carried out using Chi Square test.Results: In group II, 20%, in Group III and Group IV 80% samples have showed presence of corpora amylaecia. Incontrols 100% samples had corpora amylaecia. This difference between five groups was statistically significant.In group II, corpora amylaecia was small in size, circular, deeply basophilic and scattered. In group III, IV and V,corpora amylaecia was large in size, more in number and condensed.Conclusion: The present study concluded that corpora amylaecia appear as early as fifth decade of life. Corporaamylaecia are age and neurodegeneration related phenomena and their number and size increase with age.Deposition of the corpora amylaecia in the olfactory bulb and tract may be responsible for olfactory dysfunctionin advanced age and neurodegenerative disorders