title: Is number sense impaired in chronic pain patients?
abstract: BACKGROUND
  Recent advances in imaging have improved our understanding of the role of the brain in painful conditions. Discoveries of morphological changes have been made in patients with chronic pain, with little known about the functional consequences when they occur in areas associated with 'number-sense'; thus, it can be hypothesized that chronic pain impairs this sense.
  
  
  METHODS
  First, an audit of the use of numbers in gold-standard pain assessment tools in patients with acute and chronic pain was undertaken. Secondly, experiments were conducted with patients with acute and chronic pain and healthy controls. Participants marked positions of numbers on lines (number marking), before naming numbers on pre-marked lines (number naming). Finally, subjects bisected lines flanked with '2' and '9'. Deviations from expected responses were determined for each experiment.
  
  
  RESULTS
  Four hundred and ninety-four patients were audited; numeric scores in the 'moderate' and 'severe' pain categories were significantly higher in chronic compared with acute pain patients. In experiments (n=150), more than one-third of chronic pain patients compared with 1/10th of controls showed greater deviations from the expected in number marking and naming indicating impaired number sense. Line bisection experiments suggest prefrontal and parietal cortical dysfunction as cause of this impairment.
  
  
  CONCLUSIONS
  Audit data suggest patients with chronic pain interpret numbers differently from acute pain sufferers. Support is gained by experiments indicating impaired number sense in one-third of chronic pain patients. These results cast doubts on the appropriateness of the use of visual analogue and numeric rating scales in chronic pain in clinics and research.
authors.affiliation: Section of Anaesthetics, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK.
authors.forename: J
authors.initials: J
authors.lastname: Wolrich
authors.affiliation: NIHR CLAHRC for NWL, Department of Medicine, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Poots
authors.affiliation: Pain Medicine, Chelsea and Westminster Hospital NHS Foundation Trust, 369 Fulham Road, London SW10 9NH, UK.
authors.forename: B M
authors.initials: BM
authors.lastname: Kuehler
authors.affiliation: Pain Research, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK Pain Medicine, Chelsea and Westminster Hospital NHS Foundation Trust, 369 Fulham Road, London SW10 9NH, UK.
authors.forename: A S C
authors.initials: AS
authors.lastname: Rice
authors.affiliation: Section of Anaesthetics, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK.
authors.forename: A
authors.initials: A
authors.lastname: Rahman
authors.affiliation: Section of Anaesthetics, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK Pain Medicine, Chelsea and Westminster Hospital NHS Foundation Trust, 369 Fulham Road, London SW10 9NH, UK c.bantel@imperial.ac.uk.
authors.forename: C
authors.initials: C
authors.lastname: Bantel
mesh_terms: D059787:Acute Pain / Q000175:diagnosis / Q000523:psychology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D059350:Chronic Pain / Q000175:diagnosis / Q000523:psychology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008485:Medical Audit / Q000379:methods; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D011340:Problem Solving; D055815:Young Adult
keywords: acute pain; chronic pain; hemi-spatial neglect; mild cognitive impairment
references.citation: Br J Anaesth. 2008 Jul;101(1):17-24
references.pmid: 18487245
references.citation: Neuron. 2008 Nov 26;60(4):570-81
references.pmid: 19038215
references.citation: Pain. 2010 Mar;148(3):359-360
references.pmid: 20080346
references.citation: Pain. 2005 Jan;113(1-2):9-19
references.pmid: 15621359
references.citation: Neurology. 2000 Mar 28;54(6):1324-31
references.pmid: 10746605
references.citation: J Neurosci. 2007 Apr 11;27(15):4004-7
references.pmid: 17428976
references.citation: J Neurosci. 2004 Nov 17;24(46):10410-5
references.pmid: 15548656
references.citation: Cognition. 2011 Nov;121(2):248-52; discussion 253-5
references.pmid: 21570067
references.citation: Pain. 2006 Jan;120(1-2):124-130
references.pmid: 16360267
references.citation: Can J Anaesth. 2005 Feb;52(2):137-42
references.pmid: 15684252
references.citation: Crit Care Med. 2001 Dec;29(12):2258-63
references.pmid: 11801819
references.citation: Int J Technol Assess Health Care. 2006 Spring;22(2):235-41
references.pmid: 16571199
references.citation: Z Gerontol Geriatr. 2012 Jan;45(1):45-9
references.pmid: 22278006
references.citation: Curr Opin Neurobiol. 2005 Dec;15(6):626-31
references.pmid: 16271458
references.citation: Exp Brain Res. 2006 Jan;168(1-2):254-64
references.pmid: 16044296
references.citation: Neuron. 2007 Jan 18;53(2):293-305
references.pmid: 17224409
references.citation: Anesthesiology. 2004 Sep;101(3):703-9
references.pmid: 15329595
references.citation: Neuropsychologia. 2000;38(1):93-110
references.pmid: 10617294
references.citation: Br J Clin Pharmacol. 1980 Oct;10 Suppl 2:319S-327S
references.pmid: 7437271
references.citation: Pain. 2005 Oct;117(3):412-420
references.pmid: 16153776
references.citation: Psychiatry Res. 1989 Jan;27(1):89-99
references.pmid: 2922449
references.citation: J Adv Nurs. 2011 Jun;67(6):1242-53
references.pmid: 21306422
references.citation: Int J Surg. 2010;8(2):144-50
references.pmid: 20064481
references.citation: Nature. 2002 May 9;417(6885):138-9
references.pmid: 12000950
references.citation: J Am Acad Child Adolesc Psychiatry. 2002 Feb;41(2):114-22
references.pmid: 11837400
references.citation: Cognition. 2009 Feb;110(2):198-207
references.pmid: 19095223
references.citation: Clin J Pain. 2004 Jul-Aug;20(4):207-19
references.pmid: 15218405
references.citation: Child Dev. 2004 Mar-Apr;75(2):428-44
references.pmid: 15056197
references.citation: Trends Neurosci. 1998 Aug;21(8):355-61
references.pmid: 9720604
references.citation: Neuropsychologia. 2006;44(6):860-8
references.pmid: 16260006
references.citation: Psychosom Med. 2007 Feb-Mar;69(2):144-8
references.pmid: 17327213
references.citation: Nat Neurosci. 2005 Dec;8(12):1663-5
references.pmid: 16261135
references.citation: PLoS One. 2011;6(7):e23017
references.pmid: 21829578
references.citation: Anesth Analg. 2012 Feb;114(2):410-5
references.pmid: 22075020
references.citation: Nature. 1995 Jun 8;375(6531):482-4
references.pmid: 7777055
references.citation: Pain. 2011 Apr;152(4):904-911
references.pmid: 21296501
references.citation: Eur J Neurosci. 2009 Oct;30(7):1432-42
references.pmid: 19788575
references.citation: Neurosci Lett. 1997 Mar 7;224(1):5-8
references.pmid: 9132689
references.citation: Neurosci Lett. 2001 Feb 9;298(3):195-8
references.pmid: 11165440
references.citation: Brain. 2005 Jun;128(Pt 6):1386-406
references.pmid: 15758037
references.citation: Pain. 2012 Nov;153(11):2174-2181
references.pmid: 22841878