RT Book, Section
A1 Martin, John H.
SR Print(0)
ID 1189286362
T1 Organization of the Central Nervous System
T2 Neuroanatomy: Text and Atlas, 5e
YR 2021
FD 2021
PB McGraw Hill
PP New York, NY
SN 9781259642487
LK neurology.mhmedical.com/content.aspx?aid=1189286362
RD 2024/04/18
AB CLINICAL  CASE  |  79-Year-Old  Man  With  Memory  ImpairmentA  79-year-old  man  has  become  forgetful,  often  misplacing  items  at  home,  and  sometimes  is  confused  when  paying  for  his  groceries.  His  family  reports  that  his  forgetfulness  seems  to  be  getting  worse.  On  neurological  examination,  he  reports  the  correct  date  and  knows  where  he  is  and  why  he  is  there;  he  has  normal  speech.  However,  he  is  unable  to  recall  three  unrelated  words  5  minutes  after  correctly  repeating  them.  When  asked  to  perform  simple  addition  and  subtraction,  he  is  slow  and  has  difficulty.  His  mental  status  was  further  evaluated  by  neuropsychological  testing,  which  revealed  additional  cognitive  impairments.Magnetic  resonance  images  (MRIs)  of  the  patient  and  a  healthy  control  are  presented  (Figure  1–1A1–4,  B1–4).  In  these  images,  which  were  obtained  using  a  particular  MRI  protocol  termed  T1  weighting,  white  and  gray  matter  of  the  brain  appear  as  different  shades  of  gray  and  cerebrospinal  fluid,  black.  Cranial  fatty  substances  (eg,  in  skin  and  the  bony  orbits)  are  white.  Note  how  the  ventricles,  which  are  fluid-filled  cavities,  are  thin  in  the  healthy  brain  (right  column),  but  dilated  in  the  brain  of  the  patient  (left  column).  Note  also  how  the  gray  and  white  matter  are  both  thick  in  the  healthy  brain  and  thinner  in  the  patient’s  brain.  The  hippocampal  formation  (Figures  1–1A4,  B4,  1–10A;  see  Chapter  16)  also  is  atrophic  in  the  patient’s  brain.  The  generalized  cortical  atrophy  and  ventricular  enlargement  are  also  apparent  on  the  other  MRIs.The  patient  died  several  years  later  after  developing  severe  dementia.  At  autopsy,  his  brain  was  found  to  show  clear  evidence  of  degeneration  compared  with  the  brain  from  a  healthy  person  (A5,  B5).  The  gyri  of  the  cerebral  cortex  are  narrow,  and  the  sulci  are  widened.  By  contrast,  the  external  characteristics  of  the  brain  stem  and  cerebellum  were  unremarkable.You  should  try  to  answer  the  following  questions  based  on  your  reading  of  the  chapter  and  inspection  of  the  images.  Note  that  the  description  of  key  neurological  signs  that  follow  the  questions  also  will  provide  the  answers.1.  Why  is  the  ventricular  system  affected,  even  though  it  is  a  non-neuronal  structure?2.  Are  some  brain  areas  more  severely  affected  than  others  in  the  patient?3.  Among  the  various  brain  regions  affected  by  the  neuropathological  process,  which  is  most  closely  associated  with  the  patient’s  memory  impairment?4.  Autopsy  revealed  that  the  density  of  acetylcholine-containing  neurons  in  a  part  of  the  forebrain  was  severely  reduced  in  the  patient.  What  impact  might  this  have  on  the  function  of  cortical  neurons?5.  At  autopsy  it  was  discovered  that  the  patient  had  large  accumulations  of  amyloid  plaques,  which  contain  beta  amyloid  protein,  as  well  as  neurofibrillary  tangles,  which  consist  of  an  abnormal  form  of  the  microtubule-associated  protein  tau.  What  is  the  significance  of  these  neuropathological  findings?ConclusionThe  patient  had  Alzheimer  disease,  which  is  a  neurodegenerative  disease.  The  disease  produced  profound  impairments  of  cognition,  including  memory  disturbances,  and  widespread  degeneration  of  the  cerebral  cortex.Key  neurological  signs  and  corresponding  damaged  brain  structuresBrain  of  person  with  Alzheimer  disease  and  healthy  brainNo  description  is  necessary;  the  amount  and  extent  of  cortical  atrophy  ...