The Cognitive Behavior Rating Scales (CBRS)
The yield of information from the CBRS is very high. For a small time investment, the examiner can gain valuable information from an important and unique source. Observer ratings such as these can potentially enhance diagnostic efforts when used in conjunction with neuropsychological tests and in cases in which the patient cannot participate in a full neuropsychological evaluation.
The CBRS consists of nine scales: Language Deficit, Agitation, Need for Routine, Depression, Higher Cognitive Deficits, Memory Disorder, Dementia, Apraxia, and Disorientation. The following is a brief description of the scales and the items comprising each scale:
Language Deficit (LD). This scale consists of 10 items which assess the common consequences of language disorder. Item content focuses on conversational confusion, difficulty in following instructions, and problems in reading, spelling, and writing.
Apraxia (AP). This 5-item-scale assesses the coordinated planning and expression of motor and procedural sequences. The items focus on skills such as dressing and executing complex actions.
Disorientation (DO). The content of this 5-item-scale refers to the patient's inability to attend to the environment and monitor everyday events, as shown in inattentiveness, confusion, and wandering.
Agitation (AG). Brain-damaged patients often express restlessness and poor impulse control. The 6 items on this scale focus on aggressive behavior, frustration tolerance, emotional distress, and restlessness.
Need for Routine (NR). Many brain-damaged patients with memory disorders are unable to tolerate contact with unfamiliar people or changes in routine activities. The over-reliance on familiar settings often represents an attempt by the brain-damaged person to manifest competence within a familiar context. The 7 items on this scale focus on the need for structure and routine.
Depression (DEP). This scale was included to allow evaluation of the degree to which depression contributes to the patient's pattern of impairment. The content of the 24 items focuses primarily on depressive symptoms such as depressed mood, psychomotor retardation, and decreased motivation. A comparison of scores on this scale with scores on scales assessing cognitive functions helps to clarify the role of depression in the patient's overall clinical picture.
Higher Cognitive Deficits (HCD). The 12 items on this scale center on activities which require higher-order cognitive skills, such as memory, language, abstract reasoning, and motor execution. The items require the rater to scale such global abilities as driving, managing money, and social judgment. Impairment of these activities implies that one or more of the component skills are impaired.
Memory Disorder (MD). Items which make up the Memory Disorder Scale reflect the common consequences of impairment in ability to store and recall information. The 21 items cover specific functions such as remembering the names of friends, recalling phone numbers, and remembering to tum off household appliances.
Dementia (DEM). The 26 items comprising this scale represent common behavioral signs of diffuse brain damage or disease. Specific content areas queried by the items include night time wandering, suspiciousness, deterioration of personal habits, incontinence, loss of interest in hobbies, and decline in activities of daily living.
Reliability and Validity
Reliability and validity analyses were accomplished by analyzing CBRS data from three groups of subjects. The first group consisted of 30 demented patients whose families were members of a local chapter of Alzheimer's Disease and Related Disorders Association (ADRDA). These subjects were rated by their children and spouses. The demented patients were selected using DSM-III criteria (American Psychiatric Association, 1980) and research criteria outlined by Berg et al. (1982). All were previously given the diagnosis of Alzheimer's disease by a neurologist or internist specializing in gerontology after performing a medical examination that included complete neurological, hematological, and radiological studies. Demented patients were excluded if they had any history of psychiatric disorder, cerebral vascular accident, or other brain disease. All of the demented patients were living at home at the time the CBRS ratings were completed.
The second group of subjects consisted of 30 normal individuals who were matched pairwise with the demented patients on the basis of age and years of education. These subjects were also rated by either a spouse or child. The third group of subjects consisted of 400 normal subjects, who were recruited using advertisements and announcements to the membership of the ADRDA. Normal subjects were excluded if they had any history of brain disease or psychiatric disorder. CBRS ratings for this group were also completed by either a spouse or child. Test-retest reliability was assessed by collecting CBRS ratings on 31 of the normal subjects, using a one week test-retest interval. Test-retest correlation coefficients ranged from .61 to .94. Internal consistency reliability was calculated using scores from the sample of 400 normal subjects. The alpha coefficients for the nine CBRS scales ranged from .78 to .92.
Concurrent validity studies were accomplished by comparing the ratings of the matched normals with the ratings of demented patients using paired T-tests and nonstepwise discriminant function analysis. Comparisons of scale scores revealed significantly lower ratings for demented patients on all scales except Depression. Nonstepwise discriminant function analysis was used to establish a classification rate for the rating scale. This resulted in a canonical correlation of .91; 100 percent of these demented and matched normal subjects were correctly classified using the CBRS.
A normative sample (N=688) was recruited by public newspaper advertisements and by announcements to the membership of the local Alzheimer's Disease and Related Disorders Association and the American Association of Retired People. All of these volunteers were screened for neurological and psychiatric disorders. A family member who lived with the subject was asked to complete the CBRS.