The Relationship Between The Pattern Of Odor Dysfunction And Disease Severity In Patients With General Paresis Of The Insane

Background:Syphilis(Neurosyphilis,NS)is an infectious disease caused by the invasion of syphilis spirochetes into the central nervous system,and in late stages will probably develop further into general paresis of the insane(GPI).Multiple neurological impairments were present in the GPI,while it was unclear whether the olfactory system was impaired.The aim of this study was to compare the differences in demographic characteristics,cognitive function,neuropsychiatric symptoms,pleasant olfactory experience and olfactory function between GPI patients and normal subjects,and to explore the relationship between olfactory function and cognitive function,neuropsychiatric symptoms,biochemical indicators and abnormal brain structures in GPI patients.Methods:Forty patients with GPI and twenty normal healthy contorls(NC)were consecutively recruited into this study,and basic demographic information was collected on all subjects,and clinical symptoms,biochemical indices and clinical brain imaging indices of GPI patients were collected by the researchers.The researchers assessed the scale and the olfactory test separately for the two groups of subjects.The Mini-Mental State Examination(MMSE),Clinical Dementia Rating scale(CDR),and Neuropsychiatric Inventory(NPI)were used to assess cognitive function,dementia severity,neuropsychiatric symptoms in all subjects.The Fazekas scale was used to assess white matter hypersignal and The visual rating of medial temporal lobe atrophy(MTA)was used to assess the degree of hippocampal atrophy.The olfactory function tests mainly include olfactory threshold,olfactory discrimination and olfactory identification.Chemosensory Pleasure Scale was used to olfactory pleasant experience.Results:Independent sample s t-test revealed significant differences between the GPI and NC groups in global cognition(t=9.59,p<0.001),olfactory threshold(t=4.88,p<0.0001),olfactory discrimination(t=7.10,p<0.001),olfactory identification(t=6.48,p<0.001),total olfactory score(t=8.41,p<0.001),total NPI score(t=210.00,p<0.001)and olfactory pleasant experience score(t=4.18,p<0.001);there were also significant differences in olfactory adaptation between the two groups(t=3.13,p=0.031);partial correlation analysis suggested that olfactory discrimination scores correlated with the hallucination factor in patients with GPI(r=-0.384,p=0.028),and olfactory discrimination scores correlated with global cognition(r=0.531,p=0.001),cerebrospinal fluid leukocyte count(r=-0.429,p=0.026)and syphilis titer(r=-0.381,p=0.050)and WMH(r=-0.370,p=0.031)in GPI patients;and total olfactory score was correlated with global cognition(r=-0.439,p=0.007)and WMH(r=-0.382,p=0.028)in GPI patients.In both groups of subjects,global cognition(MMSE)mediated the difference in olfactory identfication scores between the two groups as a mediating variable,with an indirect effect of 1.758(95%confidence interval[0.770;2.937])on olfactory identification scores.Conclusions:Most patients with GPI had impaired olfactory thresholds,olfactory discrimination,olfactory discrimination,olfactory adaptation,and olfactory pleasure experience.The impaired olfaction was associated with global cognition,Hallucinations,cerebrospinal fluid syphilis titer and number of white blood cells,andWMH;MMSE as a mediating variable partially mediated the difference in olfactory discrimination between GPI patients and normal controls,and did not mediate olfactory adaptation,olfactory threshold,olfactory discrimination,or total olfactory score.The present study suggests that olfactory receptors,peripheral,primary central and higher central links in the olfactory pathway are impaired in GPI patients.Whether there is an association between olfactory function and changes in GPI patients requires continued follow-up studies combined with additional biochemical indicators and more comprehensive brain imaging.