Cognitive impairment (CI) can develop during the course of ageing and is a feature of many neurological and neurodegenerative diseases. Many individuals with CI have substantial, sustained, and complex health care needs, which frequently include pain. However, individuals with CI can have difficulty communicating the features of their pain to others, which in turn presents a significant challenge for effective diagnosis and treatment of their pain. Herein, we review the literature on responsivity of individuals with CI to experimental pain stimuli. We discuss pain responding across a large number of neurological and neurodegenerative disorders in which CI is typically present. Overall, the existing data suggest that pain processing is altered in most individuals with CI compared with cognitively intact matched controls. The precise nature of these alterations varies with the type of CI (or associated clinical condition) and may also depend on the type of pain stimulation used and the type of pain responses assessed. Nevertheless, it is clear that regardless of the etiology of CI, patients do feel noxious stimuli, with more evidence for hypersensitivity than hyposensitivity to these stimuli compared with cognitively unimpaired individuals. Our current understanding of the neurobiological mechanisms underpinning these alterations is limited but may be enhanced through the use of animal models of CI, which also exhibit alterations in nociceptive responding. Further research using additional behavioural indices of pain is warranted. Increased understanding of altered experimental pain processing in CI will facilitate the development of improved diagnostic and therapeutic approaches for pain in individuals with CI.
aDepartment of Physical Therapy and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
bDepartment of Psychology, University of Turin, Turin, Italy
cDepartment of Basic Medical Science, Neuroscience and Sense Organs, Bari University, Bari, Italy
dInstitute of Clinical Pharmacology and Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University of Frankfurt, Frankfurt, Germany
eInstitute for Medical Research, University of Belgrade, Belgrade, Serbia
fDepartment of Pharmacology and Therapeutics, School of Medicine, NCBES Centre for Pain Research and Galway Neuroscience Centre, National University of Ireland, Galway, Ireland
gInstitute of Neuroscience and Department of Psychiatry and Forensic Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
hDanish Dementia Research Centre and Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
iDepartment of Physiological Psychology, University of Bamberg, Bamberg, Germany
jDonders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, the Netherlands
kCenter for Sensory-Motor Interaction (SMI), Aalborg University, Aalborg, Denmark
lDepartment of Anatomy and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
mDepartment of Pharmacology, Faculty of Medicine, Clermont University, Clermont, France
nDepartment of Psychology and Behavioral Sciences, Aarhus University, Aarhus, Denmark
Corresponding author. Address: Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Haim Levanon St., Tel Aviv 69978, Israel. Tel.: +972-3-6405431; fax: +972-3-6409223. E-mail address: email@example.com (R. Defrin).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received January 24, 2015
Received in revised form April 07, 2015
Accepted April 09, 2015