What symptoms predict the diagnosis of mania in persons with severe/profound intellectual disability in clinical practice?

Background While researchers have attempted to address the difficulties of diagnosing affective disorders in the intellectually disabled population, diagnosing bipolar disorder in an individual with severe intellectual disability (ID) remains a challenge. The aim of this study was to identify what symptoms can predict a diagnosis of mania in the intellectually disabled population. Methods Three groups of persons with ID participated in this study: (1) individuals with a bipolar diagnosis who were currently manic; (2) individuals with an Axis I diagnosis other than bipolar disorder; and (3) individuals without an Axis I diagnosis. Two recognized measures of mania (i.e. Diagnostic Assessment for the Severely Handicapped‐Revised and Parent Version of Young Mania Rating Scale) were used to evaluate symptoms of mania. A logistical regression procedure was conducted on mania items to identify which items correctly identify persons with ID who were currently manic. Results Psychomotor agitation, decreased sleep, changes in mood and aggression were significantly related to the diagnosis of mania. Further, psychomotor agitation and disturbed sleep were significant predictors of a diagnosis of mania. Conclusions Problems of sleep and psychomotor agitation should alert clinicians that further assessment of bipolar symptomatology is warranted. Focusing on observable behaviours based on Diagnostic and Statistical Manual of Mental Disorder‐IV criteria can be useful in formulating a diagnosis of bipolar disorder in persons with ID.     

Challenging behaviors should not be considered depressive equivalents in individuals with intellectual disabilities. II. A replication study

Previous research has proposed behavioral equivalents for depression, but evidence for behavioral equivalents has been contradictory. The relationship between a measure of depression and several proposed behavioral equivalents of depression was assessed in 693 adults living in a large residential setting. Most were adults with severe or profound intellectual disability. The frequency of language-based measures of depression was very low. A scale to assess depression was constructed based on an item analysis of a larger pool of items. Both item and factor analysis and correlations between scores on the depression scale and individual maladaptive behavior items showed little or no relationship between proposed behavioral equivalents and depression. No support was found for behavioral equivalents of depression. This replicated the findings of Tsiouris, Mann, Patti, and Sturmey (2003). Practitioners are cautioned against using maladaptive behaviors as evidence of depression in people with severe or profound intellectual disabilities.     

A critical item analysis of the QABF: Development of a short form assessment instrument

Due to the relative inability of individuals with intellectual disabilities (ID) to provide an accurate and reliable self-report, assessment in this population is more difficult than with individuals in the general population. As a result, assessment procedures must be adjusted to compensate for the relative lack of information that the individual may be able to provide and rely more on the behavioral expression of communication. One method commonly used is the indirect functional assessment that utilizes behavior rating scales developed to gather behavioral data in a short time. One of the few empirically derived and psychometrically sound scales is the Questions About Behavioral Function (QABF), a 25-item questionnaire designed to rate specific behavioral functions and maintaining variables. The purpose of this study was to use both exploratory and confirmatory factor analytic procedures to examine the psychometric properties of the QABF, conduct an item analysis, and determine if a short form version could be developed that is both psychometrically valid and reliable, and clinically useful. Results of the item selection procedure indicated that the original 25 items could be reduced to 15. Evaluation of the 15-item short form showed that the QABF-SF maintained the original five-factor structure of the original form, while maintaining an equivalent degree of reliability and validity. The QABF-SF appears to be a useful tool to aid clinicians in the brief functional assessment of behavior in individuals with ID.     

The relationship between manic symptoms on the DASH II and YMRS and feeding/mealtime behavior problems

This study represents the first to assess whether a relationship between manic symptoms and feeding/mealtime behavior problems exists in individuals with ID. Participants were compared across three groups (manic, non-manic psychiatrically impaired, and controls) on the diagnostic assessment for the severely handicapped-revised (DASH-II) and young mania rating scale (YMRS) and items of the screening tool of feeding problems (STEP). Individuals in the manic group exhibited clinically significant symptoms of mania (n=18), those in the non-manic psychiatrically impaired group exhibited symptoms of psychopathology other than mania (n=18), and those in the control group did not exhibit symptoms of mania or any other psychopathology (n=18). Significant differences were found across the groups for a number of items. Specifically, individuals exhibiting symptoms of mania were significantly more likely to 'continue to eat as long as food was available', 'to require special positioning during feeding, and 'to engage in problem behaviors during mealtime (e.g., aggression)'. These individuals were also significantly less likely to 'eat foods of only certain textures'. Implications of these data are discussed.     

Assessment of the relationship between diagnoses of ASD and caregiver symptom endorsement in adults diagnosed with intellectual disability

Individuals diagnosed with an intellectual disability (ID) share overlapping traits with those diagnosed with both ID and an Autism Spectrum Disorder (ASD). Therefore, the purpose of this study was to determine if caregivers' reports of symptoms of ASD are of value (i.e., when comparing them to clinical diagnoses of ASD) and to determine which symptoms of ASD best differentiate those with ASD from those with ID only. It was hypothesized that a subset of items would emerge using the Autism Spectrum Disorders-Diagnostic for Adults (ASD-DA) which would differentiate the two groups utilize in this study. One hundred eighty-six adults diagnosed with ID with and without diagnosis of ASD were assessed for core symptoms and other behavioral differences using the ASD-DA. Most of the individuals in the ID group (n=93) and the ID plus ASD group (n=93) were in the profound range of ID. The items which were most likely to distinguish individuals with ASD were in socialization domain. Furthermore, adults with ASD were more likely to be male and to be non-verbal.     

Behavioural equivalents of anxiety in children with fragile X syndrome: parent and teacher report

Background Identifying many of the diagnostic criteria for anxiety and depression in individuals with intellectual disability (ID) can be challenging because they may be unable to recognize and communicate their emotional experiences accurately. The purpose of this study is to identify behavioural equivalents of anxiety in children with fragile X syndrome (FXS), the leading inherited cause of ID. Methods Parents and teachers of 43 children (aged 6–14 years) with full mutation FXS completed two standardized questionnaires on children’s problem behaviour and psychiatric symptoms. Items from the questionnaires thought to be possible behavioural equivalents of anxiety were identified and grouped into four domains: Avoidance Behaviours – Confrontational; Avoidance Behaviours – Non‐confrontational; Anxiety Continuum Behaviours; and Behavioural Dysregulation. The mean rating for the four groups of items was used to predict the children’s status for exhibiting significant problems with anxiety as defined by the Diagnostic and Statistical Manual of Mental Disorders‐oriented Anxiety Subscale from the problem behaviour scale. Results The predictor variables classified 81% (parent rating) and 86% (teacher rating) of the children correctly. Avoidance Behaviours – Confrontational and Avoidance Behaviours – Non‐confrontational (teacher rating) and Anxiety Continuum Behaviours (parent and teacher rating) made unique contributions to the models. Conclusions Children who are unable to identify and communicate that they worry about general day‐to‐day events may exhibit more observable behaviours resembling active and passive avoidance (e.g. arguing, avoiding difficult tasks, staring off) or have specific phobias and compulsions. These findings suggest that there are behavioural equivalents for anxiety disorder in children with FXS and, more generally, support the notion of behavioural equivalents in ID.     

Assessment of the relationship between diagnoses of ASD and caregiver symptom endorsement in adults diagnosed with intellectual disability

Individuals diagnosed with an intellectual disability (ID) share overlapping traits with those diagnosed with both ID and an Autism Spectrum Disorder (ASD). Therefore, the purpose of this study was to determine if caregivers’ reports of symptoms of ASD are of value (i.e., when comparing them to clinical diagnoses of ASD) and to determine which symptoms of ASD best differentiate those with ASD from those with ID only. It was hypothesized that a subset of items would emerge using the Autism Spectrum Disorders-Diagnostic for Adults (ASD-DA) which would differentiate the two groups utilize in this study. One hundred eighty-six adults diagnosed with ID with and without diagnosis of ASD were assessed for core symptoms and other behavioral differences using the ASD-DA. Most of the individuals in the ID group (n = 93) and the ID plus ASD group (n = 93) were in the profound range of ID. The items which were most likely to distinguish individuals with ASD were in socialization domain. Furthermore, adults with ASD were more likely to be male and to be non-verbal.     

An Exploratory Factor Analysis and Construct Validity of the Resident Choice Assessment Scale With Paid Carers of Adults With Intellectual Disabilities and Challenging Behavior in Community Settings

Introduction: The Resident Choice Assessment Scale (RCAS) is used to assess choice availability for adults with intellectual disabilities (ID). The aim of the study was to explore the factor structure, construct validity, and internal consistency of the measure in community settings to further validate this tool. Method: 108 paid carers of adults with ID living in supported accommodation and residential care facilities in urban, rural, and semirural areas in England completed the RCAS. Exploratory factor analyses were performed and the construct validity and internal consistency of the emerging factors were assessed. Results: Principal axis factoring with oblique rotations suggested a scale with two factors (Everyday Choices and Participation in Household Activities) which explained 45% of the variance; the factors showed favorable construct validity as they identified significant differences between those living in residential care homes compared with supported living; the factors also differentiated between people with different levels of intellectual impairment with less choice and participation in domestic activities for those with more severe ID compared to their counterparts with moderate and mild impairment. Five items did not load onto any factor, suggesting that these could be dropped from the scale when administered in community settings, thus resulting in an 18-item measure (RCAS-18). Conclusion: The RCAS-18 may provide a useful measure to assess choice availability for people with ID supported by paid carers in the community. The revised measure may be more suitable in capturing choice than the original version for use in community samples.     

A measure of subjective burden for dementia care: the Caregiving Difficulty Scale – Intellectual Disability

Background It has been suggested in the literature on family caregiving for persons with Alzheimer's dementia (AD) that levels of objective and subjective burden among carers often predict institutionalization of the persons with AD. There is a paucity of measures to assess whether perceived burden among formal caregivers may also predict movement to more restrictive settings for persons with intellectual disabilities (ID) and AD. This study focused upon the development of a measure of subjective burden, The Caregiving Difficulty Scale – Intellectual Disability (CDS-ID) as a first step in addressing this measurement deficit. Methods An existing caregiver subjective burden scale, the Caregiving Hassles Scale (CHS) was adapted for use with 203 staff caregivers of persons with ID and AD. Preliminary testing of existing CHS items and proposed new items was carried out in two countries, Ireland and the USA. Confirmatory factor analysis with the existing items and exploratory factor analysis with existing and proposed new items for the scale was used to establish the content and test the psychometric properties of a revised scale, the CDS-ID Results On the existing CHS items, staff carers appeared to experience greater subjective burden than has been reported for family caregivers. However, the psychometric properties of the CHS found with this population were poor. Factor analysis produced a revised scale, the CDS-ID with three subscales with Cronbach alphas ranging from 0.75 to 0.93 and 38 items overall. Conclusions This new scale when used with objective burden and other scales offers an opportunity to more systematically measure the difficulties staff experience when caring for persons with ID who present with symptoms of AD.     

Identification of Post-Traumatic Stress Disorder in Individuals with Autism Spectrum Disorder and Intellectual Disability: A Systematic Review

Introduction: autism spectrum disorder (ASD) and intellectual disability (ID) seem to influence the risk of and vulnerability to exposure to trauma and adverse events. While assessment of a psychiatric disorder in ASD and ID generally is challenging, identification of post-traumatic stress disorder (PTSD) seems particularly so, and knowledge does not seem easily accessible. Methods: This article provides a systematic review of studies describing trauma reactions in individuals with both ASD and ID, including studies involving any single case with the combination of ASD, ID, and PTSD. To systematically explore PTSD symptom presentation in the group, all reported symptoms from studies were assigned by DSM-5 criteria. Results: Eighteen studies met the inclusion criteria, eight group studies and 10 case studies. Assessment methodology in studies varied, as did the format of symptom report. DSM-5 criteria provided a useful framework for integrating findings across studies, indicating that PTSD may be identified in individuals with ASD and ID. However, symptoms involving alterations in arousal and negative alterations in thought and behavior seem more easily identified than symptoms of reexperiencing and avoidance. Conclusions: There is an urgent need to identify behavioral equivalents to PTSD symptoms in this group, making it possible to identify warning signs of trauma and abuse even if such incidents are not known to family or professional carers.     

The development of a new measure for the assessment of psychopathology in adults with intellectual disability

Background   People with intellectual disability (ID) and untreated psychiatric disorder lead unnecessarily difficult and unhappy lives. The prevalence of mental illness in children and adults with ID is greater than that found in the general population. A carer-completed checklist of psychopathology that could be used with both children and adults would help identify those individuals with ID most likely to have a mental health problem, help ensure that they receive the limited services that are usually available and also assist the process of clinical assessment, diagnosis and management.
Method   This research aimed to develop a reliable and valid carer-completed checklist of psychopathology for adults with ID by redeveloping an existing measure for children with ID, the Developmental Behaviour Checklist (DBC-P). The new checklist, The Developmental Behaviour Checklist for Adults (DBC-A) was devised by changing, deleting and adding to DBC-P items. Reliability studies were conducted with paid and family carers, and DBC-A scores were compared with the results from two other measures of psychopathology.
Results   One DBC-P item was deleted, seven items changed and 12 items added. The psychometric properties of this new checklist, the DBC for Adults with ID (DBC-A), were investigated and found to be satisfactory. Intraclass correlations for test-retest and inter-rater reliability ranged from 0.72 to 0.85, and concurrent validity with two measures of emotional and behavioural disturbance was satisfactory.
Conclusions   The carer-completed DBC-A provides a broad and comprehensive survey of the emotional and behavioural problems of adults with ID. It has satisfactory psychometric properties and therefore can be used with confidence in clinical, research and service settings, and its development allows continuous assessment of psychopathology across the lifespan for all people with ID.     

An examination of specific daily living skills deficits in adults with profound intellectual disabilities

While some researchers have investigated daily living skills deficits in individuals with intellectual disability (ID) as a whole, research on specific daily living skills in a profound ID population is limited. Two hundred and four adults with profound ID residing in two large developmental centers in the southeast portion of the United States were studied. Data were collected on these individuals’ daily living skills, utilizing the Vineland Adaptive Behavior Scales (VABS). Three dependent t-tests were conducted comparing the proportion of items endorsed by informants on each of the three subdomains of daily living skills on the VABS (personal, domestic, and community). A significantly larger proportion of Personal Subdomain items were endorsed compared to Domestic or Community Subdomain items. Additionally, participants exhibited a significantly larger proportion of Domestic Skills Subdomain items compared to Community Skills Subdomain items which is consistent with theoretical models suggesting that institutional living may curb broader community skill sets. No gender differences were found in daily living skills. Lastly, individuals between the ages 30 and 39 exhibited significantly more Personal Subdomain skills than individuals who were 60 or older, while participants between the ages 30 and 39 exhibited significantly more Domestic Subdomain skills than individuals between the ages 60 and 69.     

Relationship between theory of mind and language ability in children and adolescents with intellectual disability

Background The present study was designed to evaluate the validity of the false belief task as a measure of theory of mind development in individuals with intellectual disability (ID). In most if it variants, the false belief task is linguistically demanding. This raises the possibility that the finding that individuals with ID do poorly on it might reflect language difficulties rather than theory of mind difficulties. Complicating matters further, however, is the fact that there are theoretical reasons to suppose that there might be a relationship between some dimensions of language ability and theory of mind development in individuals with ID (as well as in other populations). Method In the present study, children and adolescents with ID and typically developing (non‐verbal) mental age matches completed a standard false belief task and several tasks designed to measure language ability. Results We reasoned that a pattern in which false belief performance was correlated with all measures of language ability would reflect an artefactual relationship, whereas a more highly circumscribed, theoretically sensible pattern of correlations that was similar across both groups would support the validity of the false belief task. Conclusions The results indicated that for individuals with ID who have limited narrative language skills, those limitations contribute substantially to their failure on the false belief task. For individuals with ID who have more highly developed narrative language skills (about 40% of the sample tested), however, the false belief task may provide a valid measure of their progress towards acquiring an adequate theory of mind. This latter conclusion was suggested by the fact screening out individuals who failed to meet linguistic and cognitive prerequisites for dealing with the performance demands of the false belief task yielded non‐significant correlations between false belief performance and the language measures for both the group with ID and the typically developing comparison group.     

Psychometric evaluation of a Swedish version of the Reiss Screen for Maladaptive Behavior

Background People with intellectual disability (ID) are afflicted by mental health problems to a greater extent than other individuals, and the coexistence of ID and mental health problems involves diagnostic as well as treatment difficulties. Methods A Swedish version of the Reiss Screen for Maladaptive Behavior (RSMB), an instrument used for identification of mental health problems in people with intellectual disability (ID) was evaluated in terms of inter‐rater agreement, internal consistency, item grouping and criterion validity based on a random sample and a clinical group of adults with ID. Results The Swedish version of the RSMB had moderate‐to‐low inter‐rater agreement on specific items and good internal consistency. The total score was considered to be a fairly reliable measure of a positive or negative result on the RSMB. A principal component analysis yielded seven interpretable components. A close resemblance in sets of items between the Swedish version and the original version of RSMB was found for three subscales: Aggressive Behaviour, Avoidance Disorder and Depression (Behavioural Signs). The outcome of the criterion validity analysis indicated a higher rate of false negatives than false positives. Conclusions The potential influence of concurrent psychopharmacological treatment is discussed. It is concluded that the Swedish version of the RSMB can be used as intended by staff as a primary screening device for the identification of mental health problems among people with ID in a Swedish setting.     

Associations Between Mental Health Problems and Challenging Behavior in Adults With Intellectual Disabilities: A Test of the Behavioral Equivalents Hypothesis

Introduction: Current research findings in the field of intellectual disabilities (ID) regarding the relationship between mental health problems and challenging behavior are inconclusive and/or contradictory. The aim of this study was to further investigate the putative association between these two highly prevalent phenomena in people with ID, and specifically to explore the hypothesis that challenging behaviors may be behavioral equivalents of mental health problems. Methods: A sample of 160 adults accessing secondary care ID health services was assessed using five validated measures. These included ratings of severity of disability, mental health problems, autism behaviors, physical health problems, and four different aspects of challenging behavior. In conjunction with demographic information, four multiple regression analyses were undertaken to examine the interaction between mental health problems (moderated by severity of disability) and ratings of overall challenging behavior, aggression, self-injurious behavior, and stereotypy. In each case, age, gender, autism, and physical health problems were included as covariates. Results: There was a statistically significant association between mental health problems and ratings of overall challenging behavior, as well as the moderating effect of severity of disability. Importantly, the positive association between mental health problems and challenging behavior was only significant at more severe levels of disability. Conclusions: These findings support the “behavioral equivalents” hypothesis for mental health problems and challenging behaviors. However, further longitudinal research is required before this hypothesis can be considered unequivocally supported.     

A validity study of the Working Group's Autobiographical Memory Test for individuals with moderate to severe intellectual disability

The purpose of the present study was to investigate the validity of the Working Group's Autobiographical Memory Test as a dementia screening tool for individuals with moderate to severe intellectual disabilities (ID). Twenty-one participants with Dementia of Alzheimer's Type (DAT) and moderate to severe ID and 42 controls with similar levels of ID were tested. The majority were re-tested one year after the initial evaluation. The DAT group scored considerably lower than the control group on the initial evaluation. The controls with DS exhibited a considerable decline on the follow-up evaluation whereas other participants exhibited little changes. This demonstrates an insignificant overall difference between the DAT group and the control group on the follow-up evaluation. Virtually all participants exhibited the same scores on 3 out of 6 test items and the percentage of participants who correctly answered the remaining three test items were not significantly different from the DAT or control groups. In conclusion, the Working Group's Autobiographical Memory Test may be useful as a dementia screening tool for individuals with moderate to severe ID from DS when validated with a large sample size study. However, it is questionable whether this test is a reliable dementia screening tool for individuals with moderate to severe ID from non-DS etiologies. This test has a significant psychometric weakness because of the restricted score variability among the participants.     

Rostral and orbital prefrontal cortex dysfunction in the manic state of bipolar disorder

OBJECTIVE: This study investigated prefrontal cortex function in the manic state of bipolar disorder. METHOD: High-sensitivity [15O]H2O positron emission tomography and a word generation activation paradigm were used to study regional cerebral blood flow in five manic and six euthymic individuals with bipolar disorder and in five healthy individuals. RESULTS: Decreased right rostral and orbital prefrontal cortex activation during word generation and decreased orbitofrontal activity during rest were associated with mania. CONCLUSIONS: The data support the presence of rostral and orbital prefrontal dysfunction in primary mania. These findings, when seen in the context of the human brain lesion and the behavioral neuroanatomic literatures, may help to explain some of the neurobehavioral abnormalities characteristic of the manic state.     

Affective symptom dimensions in early-onset psychosis over time: a principal component factor analysis of the Young Mania Rating Scale and the Hamilton Depression Rating Scale

Early-onset psychosis (EOP) is a complex disorder characterized by a wide range of symptoms, including affective symptoms. Our aim was to (1) examine the dimensional structure of affective symptoms in EOP, (2) evaluate the predominance of the clinical dimensions and (3) assess the progression of the clinical dimensions over a 2-year period. STROBE-compliant prospective principal component factor analysis of Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale-21 (HDRS-21) at baseline, 6-months, 1-year and 2-year follow-up. We included 108 EOP individuals (mean age = 15.5 ± 1.8 years, 68.5% male). The factor analysis produced a four-factor model including the following dimensions: mania, depression/anxiety, sleep and psychosis. It explained 47.4% of the total variance at baseline, 60.6% of the total variance at 6-months follow-up, 54.5% of the total variance at 1-year follow-up and 49.5% of the total variance at 2-year follow-up. According to the variance explained, the mania factor was predominant at baseline (17.4%), 6-month follow-up (23.5%) and 2-year follow-up (26.1%), while the depression/anxiety factor was predominant at 1-year follow-up (23.1%). The mania factor was the most stable; 58.3% items that appeared in this factor (with a load > 0.4) at any time point appeared in the same factor at ≥ 3/4 time points. Affective symptoms are frequent and persistent in EOP. Mania seems to be the most predominant and stable affective dimension. However, depression and anxiety may gain predominance with time. A comprehensive evaluation of the dimensional structure and the progression of affective symptoms may offer clinical and therapeutic advantages.

     

A psychometric evaluation of a Swedish version of the psychopathology inventory for mentally retarded adults (PIMRA)

Given the difficulties with symptom identification and the assessment of mental health problems in persons with intellectual disabilities (ID) there has been a focus on the development of relevant assessment schedules for persons with ID. A Swedish version of the psychopathology inventory for mentally retarded adults (PIMRA, informant version), an instrument designed for identification of specific mental health problems in persons with ID, was evaluated in terms of inter-rater reliability, internal consistency, item grouping, criterion and concurrent validity based on a sample of 101 adults with different levels of ID. The Swedish version of the PIMRA had low inter-rater agreement on specific items but good agreement on low or high total score. In order to investigate internal validity, principal component analyses (PCA) were conducted in steps. Consequently, the majority of the 26 items, which remained after three PCA analyses, were grouped in a pattern approximating five of the original PIMRA subscales. The present analysis identified no item grouping matching the original Affective disorder subscale. Based on these results a revised Swedish version was developed. The concurrent validity analysis yielded a strong association between the total scores of the PIMRA and Reiss Screen for Maladaptive Behaviour (RSMB), between subscales on both instruments describing psychotic symptoms and between the RSMB subscale Aggressive behaviour and the PIMRA subscale Adjustment problems. The outcome of the criterion validity analysis indicated that individuals with a clinical diagnosis obtained higher total PIMRA scores than individuals without a clinical diagnosis and a comparison between the PIMRA subscale Psychosis and the clinical diagnosis indicating psychoses according to DSM-III-R or DSM-IV yielded a higher specificity than sensitivity measure. The results indicate that the PIMRA had a potential to identify individuals with mental health problems in persons with different levels (mild, moderate and severe) of ID and identify individuals with a specific mental disorder. Thus, professionals might use the PIMRA as a complement in the diagnostic process.     

A preliminary study of the validity of memory tests recommended by the Working Group for individuals with moderate to severe intellectual disability

Background Normal aging and Dementia of Alzheimer’s Type (DAT) among higher functioning individuals with intellectual disability (ID) have been relatively well studied using a variety of cognitive tests. However, cognitive studies for lower functioning individuals with ID are scarce in the literature. The Working Group recommended the Test Battery for the Diagnosis of Dementia in Individuals with various level of ID. Few studies have investigated whether the Test Battery is useful to study dementia among individuals with moderate to severe ID. The purpose of this study is to investigate whether the memory subtests of the Test Battery are useful for measuring memory function and studying DAT in individuals with moderate to severe ID. Methods We compared performances on the memory subtests in the Test Battery between 31 normal controls and 13 DAT patients with moderate to severe ID. Performance on the Picture Recognition Test was also compared between five normal controls and five DAT patients. This test was designed by our team to measure memory functions of individuals with moderate to severe ID. Results Among the memory subtests of the Test Battery, the Autobiographical Memory and the Orientation were found to be useful for studying normal and abnormal aging among individuals with moderate to severe ID. Preliminary data for the Picture Recognition Test demonstrated that these individuals properly responded to this test and the majority of DAT patients could be differentiated from the normal controls based on their performance. Conclusions Further studies are necessary to improve usefulness of the memory subtests of the Test Battery for lower functioning individuals with ID. While the results suggest that the Picture Recognition Test may be more effective in discriminating individuals with DAT, given the very small sample sizes, a study with larger sample sizes should be undertaken to validate these findings.