Agenda for tonight

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Agenda for tonight

• Hand in Assignment 1
• Practicum information
• Questions/thoughts about last weeks lecture
• - a short post-test

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Agenda contd

• Lecture
• - Introduction to MeSH
• - Introduction to Medline and PubMED
• Break
• Lab

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Introduction to MeSH and MEDLINE

• orWhen is a dose of 81 mg/day
• of acetylsalicylic acid to prevent heart attacks
  really aspirin/ad andmyocardial infarction/pc?

Libr538F Class 2
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Understanding MeSH

• What is MeSH?
• Organization, features, and functions of MeSH
• Tools to help identify MeSH
• Techniques to manipulate MeSH search results
• Challenges encountered when using MeSH

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What is MeSH?

• a dynamic thesaurus of controlled vocabulary used
  for indexing and cataloguing
• terms arranged in a tree structure branching from
  15 categories to subcategories to general
  descriptors to specific descriptors
• Purpose permit consistent searching at various
  levels of specificity across many
  authors/journals
• http//www.nlm.nih.gov/pubs/factsheets/mesh.html

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MeSH Tree

• Top of MeSH Tree
• Parent 1
• Parent 2
• Parent 3
• ..
• Term
• Child 1
• Grandchild 1
• ..
• Child 2
• http//www.nlm.nih.gov/mesh/meshhome.html

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Same term different tree

• Some subject headings may be in more than one
  tree
•  Dementia, Vascular C10.228.140.380.230
•  Dementia, Vascular F03.087.400.350

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MeSH Subheadings

• MeSH terms further tuned with a set of 83
  possible subheadings
• Subheadings are used with MeSH to retrieve
  frequently discussed aspects of a topic
• e.g. Dementia/drug therapy,diagnosis,economics
  psychology, etc.
• can search using certain pre-arranged Families
  of Subheadings
• AE ... ADVERSE EFFECTS
• PO ... poisoning
• TO ... toxicity

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Heart Attack

• Diseases Cardiovascular Diseases Vascular
  Diseases
• Ischemia
• Myocardial Ischemia
• Myocardial Infarction
• MeSH definition Gross necrosis of the
  myocardium, as a result of interruption of the
  blood supply to the area. (Dorland, 27th ed)
• Subheadings complications / diagnosis /
  embryology / epidemiology / etiology / metabolism
  / microbiology / surgery / therapy
• Narrower Terms Myocardial Stunning Shock,
  Cardiogenic

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Getting to MeSH

• MeSH homepage
• Entrez the Life Science Search Engine
• HealthSelect-Health on the Net Foundation
• Google

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Explode MeSH term

• Method for including all narrower terms to the
  term being searched
• E.g. exp Lower Extremity A01.378.610 Buttocks
  A01.378.610.100 Foot A01.378.610.250  
  Hip A01.378.610.400 Knee A01.378.610.450
  Leg A01.378.610.500 Thigh
  A01.378.610.750

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Focus or Major Concept

• The future of community psychiatry.Cohen CI
  et.al. Community Ment Health J. 2003,
  39(5)459-71.
• Community Mental Health Services / td Community
  Psychiatry / td ForecastingHuman
• Managed Care ProgramsSocieties, Medical

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Challenges encountered with MeSH

• Prefers use of clinical terms
• MeSH derived from Latin, Greek, English
• The (dreaded) inverted term
• Dementia, Vascular Shock, Cardiogenic
• Organs are not their disease
• Lewy bodies vs Lewy body dementia

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More challenges

• Some main headings also moonlight as subheadings
• /pathology, psychology, transplantation
• A vocabulary that is selective, incomplete
• Antipsychotic agents typicals, atypicals
• Requires some knowledge of disease state/process
• Depression vs depressive disorder
• Previous indexing terms
• Older articles indexed with terms no longer used

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Remember

• Articles are indexed to the most specific subject
  heading that fits
• Article about Binswanger disease (a vascular
  dementia) would not be indexed with the subject
  heading dementia, rather it would be indexed with
  the subject heading .?
• Cross references lead you to subject headings

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Tips for finding relevant MeSH terms

• Search for your term in the title field
  (yourterm.ti.).
• also try searching for your term as a keyword in
  the abstract title fields (yourterm.ti,ab.).
• read the "Scope Note" - keyword possibilities
  under the "Used For" section
• Try to get additional terms from your patron
• Try searching the Permuted Terms List
• remember that MEDLINE uses the generic drug name

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Intro to Medline

• What is Medline and/or PubMed
• PubMed Clinical Queries
• Vendor packaged Medline
• OVID
• Silverplatter
• SkolarMD
• Lab Exercises

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Medline

• Bibliographic database produced NLM
• Contains more than 12 million references to
  journal articles from 4800 health sciences
  journals
• It covers literature from 1951 to present day.
• It has an American bias in the literature
  coverage, spelling and descriptive terms.

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PubMed

• MEDLINE, OLDMEDLINE, In process citations
• Out-of-scope citations
• Citations that precede the date that a journal
  was selected for MEDLINE indexing.
• Some additional life science journals that submit
  full text to PubMedCentral and receive a
  qualitative review by NLM.
• links to free books on Bookshelf
• Updated daily

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PubMed/Medline Clinical Queries

• Diagnosis, Therapy, Prognosis, Reviews, Clinical
  Prediction Guidelines, Qualitative Studies,
  Etiology, Costs, Economics
• Further refined with
• Specificity Precision
• Sensitivity Recall
• Optimized

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Specificity - Precision

• Precision the number of relevant documents
  retrieved divided by the total number of
  documents retrieved.

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Sensitivity - Recall

• Recall the number of relevant documents
  retrieved divided by the total number of relevant
  documents in the index.

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To increase sensitivity

• Broaden the question
• Find more search terms from relevant records
• Try different combinations of terms
• Use truncation ( ) or wildcard (?) in title
  word or key word searches
• Explode terms, select all subheadings
• Search further back in time

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To increase specificity

• Narrow the question
• Use more specific terms in a Title Word search
• Use your term in a Keyword search
• Select more specific subheadings
• Add more terms (using AND) to represent other
  aspects of the question
• Limit search age group, sex, publication type
• Limit search local holdings

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Optimized

• In an ideal world, recall is 100. However, since
  this is impossible to achieve this, the system
  attempts to optimize both recall and precision
  simultaneously.
• Result - retrieved citations set size between
  precision and recall.

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The many faces of Medline

• PubMed
• Ovid Medline
• SkolarMD
• Silverplatter Medline

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PubMed or Medline you decide

• Directing users to either PubMed or OVID Medline
  will depend on several factors what is more
  current, comprehensive and appropriate given the
  information request?
• Can we make do with PubMed alone and neglect OVID
  MEDLINE?