Laurent Younes\, professor and chair of the Department of Applied Mathematics and Statistics at Johns Hopkins University\, will pre sent “Change Point Estimation of Brain Shape Data in Relation with Alzheim er’s Disease.”

\n**Abstract:** The man
ifestation of an event\, such as the onset of a disease\, is not always im
mediate and often requires some time for its repercussions to become obser
vable. Slowly progressing diseases\, and in particular neuro-degenerative
disorders such as Alzheimer’s disease (AD)\, fall into this category. The
manifestation of such diseases is related to the onset of cognitive or fun
ctional impairment and\, at the time when this occurs\, the disease may ha
ve already had been affecting the brain anatomically and functionally for
a considerable time. We consider a statistical two-phase regression model
in which the change point of a disease biomarker is measured relative to a
nother point in time\, such as the manifestation of the disease\, which is
subject to right-censoring (i.e.\, possibly unobserved over the entire co
urse of the study). We develop point estimation methods for this model\, b
ased on maximum likelihood\, and bootstrap validation methods. The effecti
veness of our approach is illustrated by numerical simulations\, and by th
e estimation of a change point for atrophy in the context of Alzheimer’s d
isease\, wherein it is related to the cognitive manifestation of the disea
se. This work is a collaboration with Marilyn Albert\, Xiaoying Tang and M
ichael Miller\, and was partially supported by the NIH.

*For those who cannot make it to the Homewood campus\, the semi
nar will be video-conferenced to Traylor 709 on the School of Medicine cam
pus.*

**For those who attend at Homewood\
, lunch will be provided at noon.**