یک ارزیابی اولیه از ویژگی های روان سنجی پرسشنامه اندوه بغرنج برای افراد دارای معلولیت ذهنی (CGQ-ID)

Abstract Given the research evidence that people with intellectual disability (ID) do grieve following bereavement, the present study aimed to describe and gather preliminary psychometric data for a version of the Inventory of Complicated Grief [Prigerson, H. G., Maciejewski, P. K., Reynolds, C. F., Bierhals, A. J., Newsom, J. T., Fasiczka, A., et al. (1995). Inventory of Complicated Grief: A scale to measure maladaptive symptoms of loss. Psychiatry Research, 59, 65–79] adapted for use with this population. Carers completed the Complicated Grief Questionnaire for People with ID (CGQ-ID) for 76 individuals with ID, half of whom had experienced a parental bereavement within the last 2 years. The final scale and subscales (Separation Distress and Traumatic Grief) showed very good internal and inter-rater reliability and distinguished between the two groups. While the findings suggest that the CGQ-ID is suitable for identifying complicated grief-type symptoms among adults with ID, further research must be conducted to ascertain whether the findings can be replicated.

Introduction As people with intellectual disability (ID) are living longer, more and more will experience significant life events such as bereavement. At the same time, there is a growing body of evidence from bereavement research that suggests that pathological grief symptoms (e.g. intense prolonged experience of disbelief, depression, anger and yearning) represent a distinct clinical entity within the general population (Prigerson, Vanderwerker, & Maciejewski, 2008). Within this context, there is a movement to see ‘pathological grief disorder’ included in the fifth edition of the Diagnostic and Statistical Manual for Mental Disorders ( Prigerson et al., 2008). In an effort to add to our understanding of the symptoms that may be associated with pathological or complicated grief in the general population, an assessment tool in the form of an Inventory of Complicated Grief has been developed ( Prigerson et al., 1995 and Prigerson et al., 1999). The inventory uses symptoms taken from existing psychopathology and grief symptom inventories ( Frank, Prigerson, Shear, & Reynolds, 1997) and includes separate subscales of Separation Distress and Traumatic Distress. The Inventory of Complicated Grief has been used with a number of groups and its psychometric properties have been found to demonstrate good internal consistency, as well as convergent and criterion validity, and was found to be an easily administered assessment for symptoms of complicated grief ( Prigerson & Jacobs, 2006). However, recognising the potential for grief reactions in the ID population, no assessment tool has been developed for with people with ID. This is a significant gap, given that there is clear evidence to show that people with ID experience feelings of grief and sadness following a bereavement (Dowling, Hubert, & Hollins, 2003) and their behaviour and mental health can deteriorate as a result (Dodd et al., 2005 and Hollins and Esterhuyzen, 1997). Despite the growing body of research in this area specifically, there is still a paucity of information and understanding of the symptoms that people with ID experience, as well as a lack of appropriate methods of assessment. Research by Blackman (2008) describes a tool for the assessment of support needs among this group following a bereavement, but this does not consider the issues associated with complicated grief. If professional carers and staff in organisations are to be able to support individuals who are experiencing a complicated grief reaction, it is essential that valid and reliable assessment tools are available. However, there are significant difficulties associated with researching the effects of a significant life event such as bereavement, on people with ID. First, people with ID are not a homogenous group: there are wide differences in experience, environment, personality, and ability. Secondly the grief questionnaires that are used in the general population are frequently not appropriate for use in this population because of their complexity of language and concepts used in them; examples include the Texas Revised Inventory of Grief (TRIG) (Faschingbauer, 1981), the Grief Experience Inventory (Sanders, Mauger, & Strong, 1985) and the Inventory of Complicated Grief (Prigerson et al., 1995). Therefore there is a need to develop tools that are appropriate for use with this population. The Complicated Grief Questionnaire for People with Intellectual Disabilities (CGQ-ID) is an adapted version of the Inventory of Complicated Grief (Prigerson et al., 1995). The Prigerson scale was selected for adaptation as it was believed to offer the best opportunity to explore the full range of grief reactions, up to and including more pathological forms of grief. Given the paucity of the research in this area, the challenges associated with developing self-report measures in ID, and the sensitive nature of discussing these issues with service users, the tool was initially developed as a proxy-report measure. This will allow for an initial assessment of the validity of the symptoms of complicated grief in the population and the potential of the scale to inform research in this area. Therefore the aim of this study is to describe the CGQ-ID and evaluate the psychometric properties of the tool.

3. Results 3.1. Comparability of Bereaved and Comparison groups First, the Bereaved and Comparison groups were compared statistically on demographic variables and level of functioning. No significant differences were found between the groups for gender, age, or pattern of service use. It should be noted that 19 of the Comparison group (50%) had experienced a parental bereavement; however these deaths had occurred between three and 20 years previously (M = 7.37 years, S.D. = 5.10). Within the Comparison group, CGQ-ID scores (original scale structure) for those with a parental bereavement were compared to those without a parental bereavement, in order to test the homogeneity of this group. However, independent t-tests showed no evidence of any significant differences either on the overall CGQ-ID score or the two subscales of Traumatic Grief and Separation Distress. Finally, all participants were identified as ‘high ability’ on the Index of Social Competence and no significant difference was found between the groups on total scores for this measure or on any of the subscales. 3.2. Psychometric properties of the CGQ-ID 3.2.1. Internal consistency Cronbach's alpha was used to assess the internal consistency of the overall scale. Generally scores above 0.7 are considered to represent appropriate internal consistency. Analysis of the data collected revealed an alpha score of 0.927 for the ratings given by key workers (for both the Bereaved and Comparison groups) and 0.894 for ratings by the second staff member (Bereaved group only). 3.2.2. Inter-rater reliability In order to assess inter-rater reliability of the scale two staff members (the key worker and a second carer) were asked to separately assess the individuals in the Bereaved group using the CGQ-ID. A Pearson's correlation, used to assess the relationship between the two sets of scores, yielded a significant and very strong positive correlation of 0.967 (significant at p < 0.01, r2 = 0.935) between the two sets of scores, suggesting that almost 95% of the variance in the data is explained by the relationship between the different raters’ evaluations. 3.2.3. Discriminant validity In order to test whether the CGQ-ID could discriminate between the Bereaved and Comparison groups, the two groups were compared on their overall mean score. The overall mean score was obtained by calculating a total score across all questions answered and dividing this by the number of valid answers (e.g. missing data and ‘not applicable’ responses were excluded). The highest possible score on this scale was 4.7 (as some questions had a range of 0–4 and others 0–5) with higher scores indicative of greater difficulty. One item, ‘Believes the deceased is dead’, was reverse-scored. The groups’ mean scores were compared using an independent t-test and a significant difference was found t(41) = 8.79, p < 0.01, with the Bereaved group scoring significantly higher than the Comparison group (Bereaved M = 1.13, S.D. = 0.7; Comparison M = 0.109, S.D. = 0.16) on the overall mean score. The range of total scores for the Bereaved group was 0–2.43; the Comparison group had a range of 0–0.78. 3.3. Exploration of subscales within the CGQ-ID As well as exploring the overall mean score of the CGQ-ID the data was explored for the presence of possible subscales. However, factor analysis was not conducted given that the suggested ratio of four participants to every scale item for factor analysis was not met by the sample size. However, a number of alternative analyses assisted the identification of appropriate subscales in the CGQ-ID. First, the subscales previously identified within the general population were examined. Professor Holly Prigerson was contacted (May, 2005) and asked to indicate if any of the symptoms previously included in the questionnaire had been excluded. Items 1, 12, 13, 14, 20, 21 and 23 from Table 1 were excluded at this stage and the remaining symptoms and subscales were accepted as necessary to make a diagnosis of complicated grief in the general population at the time this study was conducted. Cronbach's alpha was calculated as a measure of internal consistency of the subscales. The Traumatic Grief (TG) subscale as defined by Prigerson had an alpha value of 0.827, while the Separation Distress (SD) subscale had an alpha of 0.8736. The item-total correlations were examined for each scale and only one item in the TG subscale appeared problematic; item 9 (‘Believes the deceased is really dead’, item-total correlation = −0.013). Once this item was removed from the TG subscale, the alpha value rose to 0.868. Given that the Social/Occupational Disturbance subscale had only two items it was deemed inappropriate to consider this a coherent subscale. In order to identify the most appropriate items for use with this population, the next phase of analysis identified those items that failed to differentiate between the two groups, thus tailoring the scale to the symptoms experienced by bereaved people with ID. Chi-square analyses were used to identify the items for which there was a significant difference in the frequency of occurrence between the two groups. Table 3 indicates those items where the frequency did not differ significantly. Seven items (items 3, 8, 13, 14, 16, 17, 21) were found to show no difference in frequency between the bereaved and comparison groups, and it is interesting that three of these (13, 14, and 21) had already been excluded by Prigerson (2005). Table 3. Results of chi-square analyses comparing presence of symptoms in Bereaved and Comparison groups.*. Item Chi-square result 1. Finds it hard to do normal activities χ2(4) = 32.48, p < 0.01 2. Gets upset when thinking about the deceased χ2(4) = 42.67, p < 0.01 3. Thinks the deceased will come through the door χ2(5) = 10.36, p > 0.01 ** 4. Misses the deceased so much they cannot tolerate it χ2(4) = 14.48, p < 0.01 5. Wishes the deceased were here to look after them χ2(5) = 33.72, p < 0.01 6. Wants to revisit places they used to go to with deceased χ2(5) = 28.88, p < 0.01 7. Feels guilty if they are having a good time χ2(2) = 13.43, p < 0.01 8. Feels angry about the deceased's death χ2(5) = 10.86, p > 0.01 ** 9. Believes the deceased is dead χ2(4) = 16.52, p < 0.01 10. Finds it hard to trust people since the death χ2(4) = 17.27, p < 0.01 11. Finds it hard to feel close to people since the death χ2(5) = 16.60, p < 0.01 12. Avoids things that remind them of the deceased χ2(3) = 13.90, p < 0.01 13. Reports hearing the deceased's voice χ2(3) = 5.35, p > 0.01 ** 14. Describes the feeling of seeing the deceased χ2(3) = 5.35, p > 0.01 ** 15. Finds it difficult to feel anything χ2(4) = 22.25, p < 0.01 16. Thinks its unfair that he/she is alive χ2(2) = 6.62, p > 0.01 ** 17. Feels envious of others who have not been bereaved χ2(4) = 11.12, p > 0.01 ** 18. Feels lonely since the death χ2(5) = 44.69, p < 0.01 19. Feels insecure since the death χ2(4) = 26.08, p < 0.01 20. Grief/sadness gets in the way of activities χ2(3) = 20.74, p < 0.01 21. Feels the deceased death was their fault χ2(4) = 4.22, p > 0.01 ** 22. Speaks about the deceased when talking about other things χ2(4) = 17.68, p < 0.01 23. Avoids talking about the deceased because it is painful χ2(4) = 17.16, p < 0.01 * Alpha set to 0.01 due to number of tests being performed. ** No significant difference identified. Table options Following the analysis outlined above the CGQ-ID as well as the Prigerson subscales were revisited excluding those items that did not differentiate between the groups. With regard to the subscales, no changes were made to the Separation Distress subscale, while four items (items 3, 8, 16, 17) were removed from the Traumatic Grief subscale. In addition, item 9 (‘Believes the deceased is really dead’) was removed as it correlated poorly with both the overall scale total and the Traumatic Grief subscale total. Table 4 illustrates the symptoms and subscales for the questionnaire with the items that failed to differentiate between the two groups, removed. Table 4. CGQ-ID symptoms and subscales identified by the current study. Separation Distress-ID Traumatic Grief-ID 2. Gets upset when thinking about the deceased 7. Feels guilty if they are having a good time 4. Misses the deceased so much they cannot tolerate it 10. Finds it hard to trust people since the death 5. Wishes the deceased were here to look after them 11. Finds it hard to feel close to people since the death 6. Wants to revisit places they used to go to with deceased 15. Finds it difficult to feel anything 18. Feels lonely since the death 19. Feels insecure since the death 22. Thinks about the deceased when wanting to think about other things Other items 1. Finds it hard to do normal activities 12. Avoids things that remind them of the deceased 20. Grief/sadness gets in the way of activities 23. Avoids talking about the deceased because it is painful Table options 3.4. Psychometric properties of the final scale and subscales 3.4.1. Internal consistency The reliability of the revised overall questionnaire (CGQ-ID) was 0.922. The revised Separation Distress (SD-ID) subscale had a Cronbach's alpha of 0.868; the revised Traumatic Grief (TG-ID) subscale had a Cronbach's alpha of 0.859. 3.4.2. Inter-rater reliability Replicating our analysis of the original version of the questionnaire, Pearson's correlations were used to identify the consistency with which key workers 1 and 2 rated participants on the finalised version and subscales identified above. Significant and very strong positive correlations were found between the two raters on the CGQ-ID scale (r = 0.970, p < 0.01, r2 = 0.940), the SD-ID subscale (r = 0.959, p < 0.01, r2 = 0.919) and the TG-ID subscale (r = 0.949, p < 0.01, r2 = 0.900). The high measures of association (r2) for each correlation suggest that between 90% and 95% of the variance in the data can be explained by the relationship between the different raters’ evaluations. 3.4.3. Discriminant validity In order to test whether the CGQ-ID could discriminate between the Bereaved and Comparison groups, the two groups were compared on the overall CGQ-ID score and the two subscales (SD-ID and TG-ID). The groups’ scores on the three scales were compared using independent t-tests and the results reported in Table 5. The presence of significant differences on all three elements of the CGQ-ID and the direction of the differences (the Bereaved group consistently scoring significantly higher than the Comparison group) support the ability of the scales to distinguish between the Bereaved and the Comparison groups. Table 5. Group comparisons on the scales of the CGQ-ID. Subscale Group Mean S.D. Range tobs d.f. Sig. Overall CGQ-ID Bereaved 1.419 0.873 0–2.93 9.15 39.42* <0.01 Comparison 0.102 0.157 0–0.78 SD-ID Bereaved 1.933 1.055 0–3.83 9.93 42.06* <0.01 Comparison 0.175 0.277 0–1.17 TG-ID Bereaved 0.964 0.909 0–2.60 6.25 43.95* <0.01 Comparison 0.032 0.136 0–0.80 * No homogeneity of variance therefore degrees of freedom (d.f.) adjusted. Table options In addition, a final exploratory analysis was conducted to further test the discriminant validity of the scale. Based on the analysis reported earlier comparing the subgroups in the Comparison group, a one-way non-repeated ANOVA was conducted comparing the Bereaved group, the members of the Comparison group who had experienced a parental bereavement (albeit more than 2 years ago), and those who had no experience of parental bereavement. Significant differences were found on the overall CGQ-ID score (F = 41.31, d.f. = 2, 73, p < 0.01), SD-ID (F = 48.81, d.f. = 2, 73, p < 0.01) and TG-ID (F = 19.31, d.f. = 2, 73, p < 0.01). Post-hoc analyses using Dunnet's C showed that the Bereaved group consistently differed form the other two groups, as can be see in Fig. 1, which reports the mean scores for the three groups. Scores on CGQ-ID by level of parental bereavement. Fig. 1. Scores on CGQ-ID by level of parental bereavement.