The expression and assessment of emotions and internal states in individuals with severe or profound intellectual disabilities
Research Highlights
► Assessing emotions of people with severe/profound intellectual disabilities is hard. ► There are ways to assess other internal states within this population e.g. depression. ► This review looks at the range of methods used to do that. ► It then asks if these may be useful when assessing emotions within this population.
Introduction
The focus of this review is the expression of emotion and internal states by individuals with severe or profound intellectual disabilities and the corresponding methods of assessment. A review of this area is important in order to evaluate the current state of empirical literature and highlight the need for further research. It will be argued that researchers and clinicians should be proficient at directly assessing and interpreting the expression of internal states of individuals within this population whose ability to communicate is, by definition, significantly compromised. Expertise in this area would reduce reliance on informant opinion when making decisions with regard to diverse and fundamental issues such as physical and mental health, choice and quality of life (Ross & Oliver, 2003).
This paper opens with a broad overview of the expression of internal states and emotions; their development and role within infancy. The review will then focus on expression of emotions within individuals with severe or profound intellectual disabilities. A systematic review is then described with critique of methodology. Physical and behavioral (e.g., body posture) indicators of internal states will be discussed and evaluated and the clinical implications considered. Due to the paucity of the literature on emotions, the review will then be extended to consider methods of assessing internal states such as anxiety, depression, and pain within this population.
Finally, the review will highlight the range of methodologies and measures used to assess internal states within individuals with genetic disorders1 associated with intellectual disabilities. This is a valuable and rich literature base as many genetic disorders have well-documented atypical internal states, including excessive hunger and social anxiety, that have been successfully researched using a variety of methods. Each of these methods could further inform the literature regarding emotions and emotional expressions within individuals with severe or profound intellectual disabilities.
While there is a substantial body of literature discussing the capacity of individuals with intellectual disabilities to recognize or label other people's internal states, this will not be covered within this paper. For reviews see Owen et al., 2001, Zaja and Rojahn, 2008.
There has been debate within the literature as to what constitutes the “basic” or “fundamental” human emotions. The widely accepted basic human emotions are happiness, fear, anger and sadness, with disgust and surprise also accepted by most (Turner, 2000) but there is little consensus concerning interest, anticipation, guilt, and shame. Using mostly anecdotal evidence, Darwin (1872) suggested that since the expression of basic emotions, particularly facial expressions, are similar in humans around the world, they must have a hereditary basis. He proposed that emotions serve a function and therefore should be seen as adaptive and, arguably, essential to the survival and reproduction of species. Turner (2000) has expanded upon this work, suggesting that behavioral and facial expressions are critical to group harmony as they effectively communicate emotions, feelings, and intent. This emotion-signaling hypothesis is attracting growing interest and support (e.g., Consedine, Magai, & Bonanno, 2002).
Facial expressions of emotions play a key role in early development as they allow for communication between the pre-verbal infant and their caregiver (Spangler, Emlinger, Meinhardt, & Hamm, 2001). In order to quantify and use the information afforded by facial expressions shown by infants for the purpose of research, reliable, valid, and efficient coding systems must be used (Cohn, Zlochower, Lien, & Kanade, 1999). Two systems, both of which require extensive training procedures, code observable changes in the face: the System for Identifying Affect Expression (AFFEX; Izard, Dougherty, & Hembree, 1983; formerly known as the Maximally Descriptive Facial Movement Coding System (MAX; Izard, 1979)) and the Facial Expression Scoring Manual (FESM; Izard, 1971, Izard, 1977) and the Baby Facial Action Coding System (Baby-FACS; Oster, 2000; based upon the Facial Action Coding System (FACS; Ekman & Friesen, 1978)). Using various methods, good face and current validity are reported (Ekman, Friesen, & Ancoli, 1980).
Using these coding systems, researchers have begun to identify the development of facial expressions in neonates and babies. Although crying is usually the first demonstration of an emotion (Oster, Hegley, & Nagel, 1992), the associated facial expression is usually coded as undifferentiated distress (Oster et al., 1992). The earliest facial expressions of emotions seen in newborns (aged 3–10 h) are in relation to taste; both positive in response to sucrose and negative in response to quinine solutions (Steiner, Glaser, Hawilo, & Berridge, 2001).
Increasing complexity of emotion expression emerges throughout the first two years of life. Using the FESM, basic emotions can be elicited in infants ranging in age from one to ten months (Hiatt et al., 1979, Izard et al., 1980). These emotions and expressions become functionally organized in relation to the infant and their social context (e.g., Bennett, Bendersky, & Lewis, 2005), resulting in responses that are more differentiated and specific (e.g., Witherington, Campos, & Hertenstein, 2001). This coincides with the development of several important cognitive concepts, including understanding others' intentions (Izard, Hembree, Dougherty, & Spizzirri, 1983), a concept of self, emotion regulation (Stifter & Spinrad, 2002) and elaboration of an internal “affective map” (e.g., Gendler-Martin, Witherington, & Edwards, 2008). Infants begin to label their own emotions from 18–20 months of age (Bretherton, Fritz, Zahn-Waxler, & Ridgeway, 1986), a skill that is highly correlated with cognitive abilities (Bennett et al., 2005) and social behavior (e.g., Fine et al., 2003, Izard et al., 2001).
Alongside having a strong communicative function, facial expressions influence the perceived attractiveness of an infant (Power, Hildebrandt, & Fitzgerald, 1982) and consequently affect adults' reactions to them (Hildebrandt & Fitzgerald, 1978). For example, children rated as more physically attractive are treated more favorably (e.g., Adams, 1977). Infants showing positive facial expressions are also rated as “cuter” (Hildebrandt, 1983), although it is unknown if or how flexible perceptions of cuteness, and therefore adults' behaviors, are in response to changes in facial expressions.
Diverse methods of emotional expression have been consistently shown to be important during typical development, in terms of both social and cognitive functioning. It is therefore possible that differences or deficits in the expression of emotions will influence these developmental domains. This has been studied in various populations in both child and adulthood, some of which will be discussed below. These studies can broaden understanding of emotional expression and its role in social communication and cognitive development in childhood and beyond.
Despite the strong similarities of facial expressions of emotions between and within cultures and, to some extent, species, some populations show impairments. These include individuals with schizophrenia, dementia, Möbius syndrome and those with severe or profound intellectual disabilities. Literature pertaining to the expression of emotions within each of these populations will be reviewed briefly.
Deficits in the expression of emotions are well documented within schizophrenia (e.g., Kring and Neale, 1996, Salem et al., 1996, Tremeau et al., 2005) using a range of methodologies (e.g., self-ratings; Schneider, Gur, Gur, & Shtasel, 1995; informant rating scales; Andreasen, 1984a, Andreasen, 1984b; and facial coding systems; Berenbaum & Oltmanns, 1992). The significant impairments in facial expression in individuals with schizophrenia are not due to reduced emotional experience; individuals report emotional experiences equal to or possibly greater than individuals without a psychiatric diagnosis (Herbener et al., 2008, Kring et al., 1993), nor are they simply due to side effects of medication (Earnst et al., 1996, Putnam and Kring, 2007). Despite little outwardly observable facial expression, sensitive methods (e.g., electromyography) have identified greater activity in muscles responsible for smiling and frowning in response to positive and negative stimuli respectively (Earnst et al., 1996). There are also recognized deficits in posed emotional expressions; although varying methodologies make it difficult to draw, firm conclusions (see Izard & Dougherty, 1982, for a discussion).
Such difficulties in both spontaneous and posed expressions alongside the dissociation between experience and expression of emotions suggests an underlying physical or neuromotor deficit (Dworkin, Clark, Amador, & Gorman, 1996) rather than a specific deficit in neural or behavioral systems that underpin the experience (Putnam & Kring, 2007). Despite this hypothesis, there has been little research published on effective interventions, medical or psychological, within this area.
Facial expressions of emotions are important communicative tools (Jakobs, Manstead, & Fischer, 1999), particularly in those who are pre-verbal (see Nelson & de Haan, 1997) or for those with impaired speech (Hemsley et al., 2001), such as individuals who develop dementia. As dementia, most notably Alzheimer's disease, progresses, declines are noted in expressive language skills (Faber-Langendoen et al., 1988, Kertesz and Clydesdale, 1994) and consequently the ability to report internal affective states (e.g., pain; see Smith, 2005, for a comprehensive review). Individuals must therefore rely on other methods to communicate.
Facial expressions, both “adaptive” and “inappropriate” (Porter et al., 1996) are enhanced in frequency and intensity in individuals in the early stages of dementia when compared to healthy controls (e.g., Kunz, Scharmann, Hemmeter, Schepelmann, & Lautenbacher, 2007). As the dementia advances, facial expressions gradually decrease (Norberg, Melin, & Asplund, 1986); by end stage dementia it is only possible to identify individual fragments of facial expressions using the FACS. However, even at this late stage, pleasant and unpleasant stimuli evoke differences in heart rate, respiratory rate and skin temperature (Asplund, Norberg, Adolfsson, & Waxman, 1991).
Akin to individuals with schizophrenia, it could be concluded that individuals with end stage dementia may still experience various emotions, but have difficulties expressing them due to neurological change. The task, therefore, for researchers and clinicians is to develop methods of reliably assessing these states within these populations.
Möbius syndrome is a rare congenital disorder associated with unilateral or bilateral paralysis of the abducen and facial cranial nerves (Mobius, 1888, cited in Gillberg & Steffenburg, 1989), although involvement from other cranial nerves is common. It is sometimes associated with a mild degree of intellectual disability and co-morbid autism (e.g., Gillberg & Steffenburg, 1989). This facial paralysis, evident from early infancy, means that individuals with this syndrome cannot produce facial expressions of emotions and often have delays or difficulties with speech (Meyerson & Foushee, 1978).
Surprisingly, there are few studies investigating methods of emotional expression within individuals with Möbius syndrome. Sjogreen, Andersson-Norinder, and Jacobsson (2001) observed impairments in facial expressions in all 25 of their participants (aged 2 months to 55 years), ranging from a mild isolated unilateral weakness to profound bilateral paralysis. Szajnberg (1994) visited one child at six, ten, and fourteen months of age and observed interactive play with both parents. He suggests that while the child was developing and adapting alternative ways of affective communication (such as hand gestures and body posture), the lack of facial expressions began to affect social interactions when the child wanted to express more complex feelings. In line with theories of emotional development, impairments in recognizing others' facial expressions are also noted (Calder et al., 2000, Giannini et al., 1984).
Cole (2008) discusses the potential impact that difficulties with expression may have on the experience and development of complex emotions. Surgery and biofeedback mechanisms are continually being trialed and reported but with small samples only (e.g., Zuker, Goldberg, & Manktelow, 2000). These areas require further investigation, combining the results of multiple methodologies (e.g., scanning, self-report, observations) in order to reach valid conclusions which may help inform interventions within this, and other populations, for whom emotional expressions are impaired.
Understanding and assessing emotions of individuals with intellectual disabilities2 is within its infancy (Clark, Reed, & Sturmey, 1991). There is considerable debate within the literature as to whether individuals with intellectual disabilities express the same range of emotions in the same way as people without intellectual disabilities. This debate has in part arisen from differences based on level of intellectual disability and, importantly, differences based upon the etiology of the intellectual disability. What has not been ascertained is whether there is a difference in the experience or expression of emotions within individuals with intellectual disabilities. This review is therefore particularly pertinent, both from a clinical and a research perspective, for understanding if and how, people without language and accompanying cognitive impairment communicate their internal states. Such knowledge, albeit in its infancy, can form the basis for assessing (and potentially intervening in) subjective experience that is likely to be strongly associated with an individual's quality of life.
We now review the literature base pertaining to the expression of emotions within individuals with severe or profound intellectual disabilities. The quantitative results of a comprehensive literature search are presented and compared to searches undertaken within sub-populations of the general population. The literature is then summarized, describing facial and behavioral expressions of emotions within this population alongside the ability of others to recognize and label such expressions. The expression of emotion within individuals on the autistic spectrum is not discussed specifically within this review but is reviewed by Bormann-Kischkel, Amorosa, and von Benda (1993).
Section snippets
Method
Computerized searches were undertaken on Web of Knowledge and Medline. Web of Knowledge searches the titles and abstracts of all journals listed within the Science Citation Index, Social Sciences Citation Index and the Arts and Humanities Citation Index published after 1981. MEDLINE searches the abstracts and titles of over 1800 journals published by Elsevier.
The specified keywords were learning disability/ies intellectual disability/ies, developmental disability/ies, mental retardation, mental
Defining severe and profound intellectual disabilities
The DSM-IV (American Psychiatric Association, 1994) and the ICD-10 (World Health Organization, 1992) classify intellectual disability into four categories based upon IQ (or estimates thereof): mild (IQ range 50–70), moderate (IQ range 35–49), severe (IQ range 20–34) and profound (IQ below 20). This review will focus upon literature and research with individuals with severe or profound intellectual disabilities as both language and sensory deficits (the importance of which will become apparent
Conclusions
This review has demonstrated the importance of observing and understanding behavioral and facial expressions of internal states in individuals with severe or profound intellectual disabilities. These expressions provide valuable insights into the internal experiences of individuals who cannot directly communicate their thoughts and feelings. The paucity of literature pertaining to the emotions of individuals with severe or profound intellectual disabilities is of concern. Only by expanding the
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