Neuropsychological Assessment of Pain Patients
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Greg J. Lamberty et al. Neuropsychological Assessment of Patients 8 NEUROPSYCHOLOGICAL ASSESSMENT OF PAIN PATIENTS Greg J. Lamberty, Carly R. Anderson, and Laura E. Krause Introduction Chronic pain, and many of the clinical disorders associated with it, is a vexing clinical challenge. The influence of pain on cognitive functioning and how to best characterize pain with psychometric measures has become a more com- mon referral question in neuropsychology practice. This is likely due to persistent efforts to identify the underlying causes of disorders like fibromyalgia and com- plex regional pain syndrome (CRPS). A simple biological explanation of these conditions would presumably allow a straightforward therapeutic approach, but the clinical reality is that chronic pain is usually associated with many complex and interacting factors, particularly where the issue of disability is concerned. Therefore, neuropsychologists are often asked to assist in evaluating patients with pain disorders, regardless of the presumed etiology. Today’s psychology practice environment is increasingly characterized by a bifurcation into clinical intervention and assessment practices. While this is dif- ficult to quantify with practice surveys or other literature, personal experience and anecdotal accounts indicate that neuropsychologists are frequently called upon to perform assessments that are not strictly neuropsychological in nature. Because neuropsychologists conduct assessments, they receive referrals to assess the psychological readiness of individuals to go through complex medical proce- dures (e.g., bariatric surgery, implantation of medical devices), to determine fit- ness for duty in high-stress occupations, or to assess the psychological/emotional adjustment of individuals with chronic pain, as examples. Health psychologists have typically done these kinds of evaluations, but many neuropsychologists have branched out into these assessment areas. Neuropsychologists are trained to assess personality, emotional, and behav- ioral functioning, as these are so frequently impacted in neurologic disease and Neuropsychological Assessment of Patients 231 neuropsychiatric disorders. Part of the evolution of the practice patterns noted earlier involves the common finding that individuals without significant neuro- logic underpinnings to their clinical presentation nonetheless complain of cogni- tive difficulties. The regularity of somatoform symptoms in neuropsychological referrals has become more of a focus in neuropsychology practice in recent times (Binder & Campbell, 2004; Lamberty, 2008) and this has likely led to neuropsy- chologists seeing more individuals with pain disorders (Greiffenstein & Bianchini, 2013). The extent to which most neuropsychologists have received specific train- ing in evaluating patients with chronic pain is unclear. While personality assess- ment is a routine part of the neuropsychological exam, this is usually done in the context of known or suspected neurologic or neuropsychiatric disorders and not necessarily as a means to facilitate treatment of specific clinical presentations. This distinction is critical in determining the nature of the evaluation to be conducted. Role Clarification in Assessment of Patients With Pain Disorders Neuropsychological Versus Psychological Assessments Even in well-established practices and hospital-based neuropsychology services there can be confusion about the nature of services provided by neuropsycholo- gists. Ideally, referral sources are familiar with what neuropsychologists can deliver in terms of assessment services, but this is often an evolving process. It is beyond the scope of this chapter to discuss practice models, though it is important for neuropsychologists to be clear about their assessment services and the kind of specialty services they might offer. Attaining competence in assessing complex patient presentations is obviously essential and this will often involve extra read- ing, workshops, and consultation with colleagues. Neuropsychologists are strongly encouraged to clarify their role with referral sources. For the purposes of this chapter, we assume that most neuropsychologists are asked to evaluate patients with pain disorders to rule out neurologic underpinnings of reported cognitive difficulties. However, in the broader psychological context it is likely assumed that a more comprehensive psychological evaluation will also be conducted. Typical neuropsychological evaluations serve a descriptive or diagnostic purpose more so than a treatment planning purpose. While diagnosis and treatment planning should coincide, a range of more specific measures have emerged from the pain literature that seek to identify qualities of the pain experience and patients’ responses to intervention as a means of evaluating treatment efficacy. Forensic Versus Clinical Assessments Distinctions between clinical and forensic practice in neuropsychology have been recognized for many years (Larrabee, 2011; Sweet, 1999). In forensic evaluations, neuropsychologists are typically asked to opine on the presence, nature, and severity 232 Greg J. Lamberty et al. of cognitive deficits, as well as significant personality, emotional, and behavioral dysfunction. The neuropsychologist’s role as an expert is to assist the trier of fact in making a determination about whether a claimant was injured or suffered dam- ages, and the extent to which other factors are involved. Broadly speaking, forensic evaluations are less likely to request specific information about treatment or inter- vention. As such, the neuropsychologist’s role is more purely evaluative. A clinical evaluation is more likely to include both a characterization of the patient’s functioning and recommendations for intervention. In this instance, the neuropsychologist will benefit from employing measures that are more descrip- tive and more associated with treatment outcome studies. The purpose of the evaluation will also determine what kinds of measures will be employed in the assessment process. If the neuropsychologist has a regular relationship with treat- ing clinicians, it is more likely that specific questions about response to interven- tions will be a focus of the evaluation. Epidemiology of Pain Disorders Prevalence estimates for pain disorders vary widely, mostly as a function of pre- sumed etiology (e.g., chronic pain, fibromyalgia, CRPS). For the purposes of this chapter we will focus on the chronic pain literature, as this broad descrip- tor is the most prevalent and widely investigated in the realm of pain disorders. Further, many conditions involving pain are viewed as indistinct and subsumed under the umbrella of chronic pain. The reader is directed to the following studies and websites for prevalence statistics related to fibromyalgia (Bennett et al., 2007; Haviland, Banta, & Przekop, 2011; www.cdc.gov; http://fmaware.org) and CRPS (Bruehl & Chung, 2007; De Mos et al., 2007; www.ninds.nih.gov; Sandroni et al., 2003). A recent internet-based survey in a nationally representative sample of more than 27,000 adults in the United States demonstrated the prevalence of chronic pain to be 30.7% ( Johannes et al., 2010). This estimate is higher than that noted in a European sample, which demonstrated a 20% rate of chronic pain in adults (van Hecke, Torrance, & Smith, 2013). Despite differences in prevalence, current literature indicates similar cross-cultural patterns, societal concerns, and contribu- tory factors related to chronic pain. A major concern is that the vast majority of individuals suffering from chronic pain are managed in primary care rather than specialty pain clinics (see van Hecke, Torrance, & Smith, 2013). It is thought that a lack of specialized knowledge among primary care providers leads to a greater reliance on prescription narcotics as a primary means of pain management. Chronic pain is associated with significant financial burden worldwide. Recent US estimates of health care costs associated with chronic pain ranged from $560 to $635 billion annually; these estimates are higher than the annual costs of heart disease ($309 billion), cancer ($243 billion), and diabetes ($188 billion) (Gaskin & Richard, 2012). European studies report a similar financial impact, with estimates Neuropsychological Assessment of Patients 233 TABLE 8.1 Modifiable and Non-modifiable Influences on Chronic Pain Modifiable Non-modifiable Pain Age Mental Health Sex Other Comorbid Conditions Cultural/Ethnic Background Smoking Socioeconomic Background Alcohol History of Trauma or Interpersonal Violence Obesity Heredity—Genetics and Environment Physical Exercise Nutrition Sleep Occupational Factors Adapted from van Hecke, Torrance, & Smith, (2013). of €200 billion annually (Institute of Medicine, 2011). These estimates are likely conservative as the presence of chronic pain complicates the symptoms, treatment, and prognosis of many other health conditions. Consequently, individuals with chronic pain and comorbid mental or physical health conditions are likely to be high service utilizers who often fail to benefit from narrow, pharmacologically based approaches to pain management. Recent epidemiological reviews identify numerous biological, psychological, and social factors that contribute to the development, maintenance, and outcome of chronic pain. These factors, categorized as modifiable versus non-modifiable (van Hecke, Torrance, & Smith, 2013), are summarized in Table 8.1. Non-modifiable Influences on Chronic Pain The prevalence