Profiles of cognitive functioning in subjects with neurological disorders.

Introduction

Cognitive deficits are significant sequelae of brain injuries and disease involving the cerebral hemispheres. Identifying cognitive impairments is often difficult because some deficits are subtle. Early and appropriate identification of cognitive deficits assist in

The Neurobehavioral Cognitive Status Examination (NCSE) is a screening test that evaluates a broad range of cognitive skills: orientation, attention, auditory and visual memory, spatial perceptual skills, calculations and reasoning.[2,3,4,8] Since each cognitive skill is scored separately, specific deficits are identified. On retesting, skill levels may be compared and changes in performance identified. When large groups of patients with similar neurological insults or disorders are tested NCSE group profiles can be developed. The group profiles can be useful in determining types of rehabilitation needs and environmental support needed by patients with certain types of neurological insults.[5,8]

The NCSE is being used at medical centers throughout the country as a screening test of cognitive functioning. Nurses commonly administer this test for nursing purposes, in inpatient and outpatient settings because of the ease in administration, inclusiveness and reliability.127 The purpose of this study was to incorporate this data and develop a data bank of NCSE profiles for a variety of neurological disorders.

Methodology

This study consolidated NCSE data already collected on subjects with neurological disorders. Members of the American Association of Neuroscience Nurses (AANN) learned about the study at national meetings and from the newsletters distributed by the AANN. These nurses represent medical centers, both acute and long-term inpatient and outpatient services; all were invited to participate in the study. This study was not intended as a cognitive evaluation study. Rather it's purpose was intended to amalgamate data from institutions already using the NCSE. Nurses currently using the NCSE were encouraged to participate by submitting their pre-existing NCSE data.

The research proposal was approved by the American Lake Veterans Administration Medical Center (ALVAMC) Research Committee. Each participating facility used the pre-approved ALVAMC approval and also obtained the necessary local approval to participate in this multicenter study. Once agreement and approval had been obtained, the participating centers submitted the NCSE face sheet, including a presumptive patient diagnosis, to the principle investigator (MC) at American Lake VAMC. Anonymity was maintained on all subjects.

Data Analysis

The raw scores from the NCSE fact sheet were entered into the computer file. Descriptive statistics, frequency, means and standard deviation were determined based on neurological diagnosis. The mean scores on the NCSE were categorized based upon neurologic diagnoses and plotted on the NCSE profile sheets (Fig 1-8).

[Figures 1-8 ILLUSTRATION OMITTED]

Results

Seven facilities submitted 804 NCSE profiles for inclusion into the data base. Age of subjects ranged from 14-98 years (mean 61 years; median 70 years). English was the first language of 98% of the subjects. Ninety-five percent were right-handed. Although the educational level ranged from no schooling to 20 years, the mean and median were 12 years of schooling.

Initially, there were more than 65 separate diagnoses; however, these were subsequently consolidated into 20 inclusive categories (Table 1). The number of participants in each of the diagnostic groups ranged from 1-233 (Table 1).

Table 1. Diagnostic Category Sample Size

1     Alzheimer's/Picks disease           233}
2     Multi-infarct dementia               10}    440
3     Dementia of unknown etiology        197}
4     Traumatic brain injury              197
5     Sleep disorders                      53
6     Stroke                               33
7     Subarachnoid hemorrhage              16
8     Hypoxia                              14
9     Tumor                                13
10    Neurosis                              9
11    Metabolic                             8
12    Alcohol and drug use                  7
13    Parkinson's disease                   5
14    Age-adjusted memory impairment        5
15    Hydrocephalus                         3
16    Subdural hematoma                     3
17    Psychosis                             3
18    Multiple sclerosis                    3
19    Aneurysm/AVM unruptured               3
20    Infection                             1

The NCSE profiles demonstrated discrete patterns of cognitive deficits for the different neurological disorders. Alzheimer's/Picks diseases, dementia of unknown etiology and multi-infarct dementia were combined into one diagnostic category which produced a sample size of 440 subjects (Fig 1). The NCSE profile for these subjects demonstrated a decline in orientation and moderate to severe impairment in constructional skills, verbal and auditory memory. Reasoning was measured asking participants to describe similarities between objects. The ability to abstract was impaired in this group of participants while attention and language skills were preserved.

The NCSE profile of 182 subjects with traumatic brain injury differed from the dementia profile. The brain injury NCSE profile demonstrated a minimal decline in auditory memory (Fig 2). No significant areas of cognitive decline were pathognomonic for head injury. This population included mild and severe head-injured subjects.

The NCSE of the 53 subjects with sleep disorders demonstrated decline in auditory memory (Fig 3). Visual memory was impaired in about half of the subjects with sleep disorders.

Sleep-disturbed and head-injured patients had similar cognitive patterns: impairment of auditory memory without impairment of orientation and intact reasoning. Sleep-disturbed patients had more difficulty with auditory memory than head-injured participants (Figs 2,3).

Participants with stroke showed a decline in auditory and visual memory as well as impairment in constructional ability in the mild to moderate range (Fig 4). Comparing NCSE profiles demonstrates that the profiles of stroke participants differed from those with other disorders. Specifically speech, orientation and calculations were better than anticipated especially as compared with subjects in the dementia group (Fig 1), the multiple sclerosis group (Fig 6) and the hydrocephalus group (Fig 8).

Even groups with a small number of participants illustrated unique NCSE profiles. The NCSE profiles of five subjects with Parkinson's disease demonstrated a moderate deficit in orientation and construction, and a significant decrement in auditory and visual memory (Fig 5). Calculations, reasoning and language skills were in the low normal to mildly impaired range. This pattern is consistent with the global neurologic deficits commonly seen with Parkinson's disease.6

Participants with multiples sclerosis (n=3), demonstrated a broad range of cognitive deficits. Auditory and visual memory, construction, reasoning and calculations were the areas most affected in the mild to moderately impaired range. The patients also showed evidence of language impairment, especially in identifying and naming objects on a drawing even while they were able to comprehend and repeat sentences. The one study participant with central nervous system infection demonstrated deficits in visual and auditory memory; the participant was unable to remember any of four items after five minutes. This deficit was evident despite the fact that the patient was alert and oriented to time, place, person and situation and language skills were intact (Fig 7).

Participants with hydrocephalus (n=3) demonstrated moderate deficits in auditory and visual memory and construction. Their reasoning was impaired and they demonstrated the most difficulty in abstract reasoning. They also had language difficulty and problems with simple calculations (Fig 8).

When the entire group of 804 NCSE profiles were evaluated singularly and by diagnostic groups, unique patterns of deficits emerged. The major cognitive deficits were in areas of visual and auditory memory, spatial perceptual construction and orientation. Verbal reasoning was preserved even when there was a memory deficit or difficulty with constructional skills. Reasoning and verbal judgment were impaired only in the subjects with dementia, Parkinson's disease and multiple sclerosis, even when language was preserved.

The NCSE is useful in identifying cognitive deficits. Four diagnoses had a large enough sample to be representative of the neurological disorder (Table 1). Even the NCSE profile of the single subject provided useful information about isolated cognitive deficits which is clinically relevant. The most common cognitive dysfunctions associated with neurological disorders were memory, construction and orientation. Preservation of language was surprisingly robust. However, since the NCSE requires verbal communication, the test could not be administered to those with profound language impairment and may therefore skew the data.

The similarities between the data from the sleep disorder and head-injured groups were surprising. The behavioral difficulties commonly noted with head-injured subjects may reflect affective rather than cognitive deficits and therefore were not measurable on the NCSE.[5] Memory deficits noted with sleep disorders are reversible after treatment.[1] Subjects with sleep disorders in this study were all tested prior to treatment.

Subjects with Alzheimer's, multi-infarct dementia and dementia of unknown etiology had similar NCSE patterns. Each of the patterns was so closely related that they could be superimposed one upon another and therefore were treated as one entity in this study. The only difference was in the severity of the deficits. Orientation, construction, auditory and visual memory were affected first, followed by difficulty in verbal judgment and finally changes in language skills. The term, dementia, is really related to cognitive ability and therefore may be a misleading diagnostic category since it is not a neurologic disease per se.[7]

Limitation of the Study

Several years before this study was undertaken, investigators conducted a training program to teach how to administer and score the NCSE. It is not known whether the participants in that training program were data collectors in the study. It is also not known how the various participating institutions were familiar with the NCSE and no formal review process of how the NCSE was administered was conducted. The one consistent aspect was that everyone received the same training manual and the principle investigators were available for consultation throughout the study. The NCSE training manual is simple, the test itself is easy to administer and score, and results are repeatable and reliable.[4]

Although there were 804 NCSE profiles, there were too many categories of diseases, twenty, to be able to use the information collectively in a meaningful way. Subjects with similar diagnoses, such as dementia, traumatic brain injury and various types of stroke, were grouped within their diagnostic group regardless of severity of injury or disease. When subjects with minimal and severe injury are grouped together there is loss information in the averaging of the NCSE scores. In future studies it would be useful to discriminate between the severity of the head injury, types of stroke and etiology of the dementia to further define the cognitive deficit associated with specific neurologic insult. Sometimes group data will significantly underreport the severity of the cognitive deficit in an individual patient.

Recommendations for Future Study

Ideally this study should continue and more NCSE data be collected, especially since the NCSE is being used more frequently by nurses in clinical practice and readily available. A larger sample size within each of the diagnostic groups would help identify more specific cognitive deficits and patterns. Further study should also focus on the relationship between cognitive deficits and activities of daily living. Intervention studies could also be developed. For example, a study may be done to determine which types of cognitive deficits respond better to color or environmental changes or data maybe used to assist in planning appropriate levels of care for patients with cognitive difficulties.

The most important aspect of the study is that NCSE profiles were developed for four different neurologic diagnoses. The NCSE illustrates different patterns based on diagnoses even in these heterogeneous subgroups. A data base for investigators interested in further research has been established and is accessible though the American Association of Neuroscience Nurses. Enough NCSE profiles were developed to suggest that populations do indeed differ according to their neurologic disorders. Now it is particularly important to determine the relationship between NCSE profiles and the subjects' ability to function in day to day life. Once that relationship is established, intervention studies can be undertaken to improve quality of life for patients with neurologic disorders.

Summary

This was a multicenter study to develop a data base of neurocognitive profiles on subjects with a variety of neurological disorders. Seven medical centers participated in the study and submitted 804 NCSE profiles. Four diagnostic groups were large enough to demonstrate cognitive deficits that could be considered characteristic for the entire group. Broad areas of deficits, such as orientation, constructional skills and verbal and auditory memory, were particularly sensitive and had declined as a result of those insults. Of equal importance is that even individual NCSE profiles provided specific information about cognitive deficits. The NCSE is useful for group and individual evaluations and is a valuable tool for nurses in clinical practice in a variety of clinical and home care settings.

Acknowledgment

This study was conducted with the financial support of the American Association of Neuroscience Nurses. The investigators are most appreciate of the support of the national office for their assistance during the course of the study. The investigators are grateful for the participation of the institutions and patients throughout the country in making this study possible and to Jane Samonds, RN for data entry.

Co-Principle Investigators: Margarethe Cammermeyer, RN, PhD, CNRN, RNP Virginia Prendergast, RN, MSN, A GNP Investigators: Rebecca Veltman, RN, MS Susan Jones, OTR Janet Samuels, RN Cathy Campbell, RN, BSN Mary Madrid, RN, PhD Pamela Meck, RN, BA, CNRN

References

[1.] Cammermeyer M: Sleep fragmentation of oxygen desaturation as etiology of cognitive disability with obstructive sleep apnea. Dissertation Abstract, 1991.

[2.] Cammermeyer M, Evans J: A brief neurobehavioral exam useful for early detection of postoperative complications in neurosurgical patients. J Neurosci Nurs 1988; 20(5):314-323.

[3.] Catenzaro M: Personal communication, 1990.

[4.] Kiernan RJ, Mueller J, Langston JW, VanDyke C: The Neurobehavioral Cognitive Status Examination: A brief but differentiated approach to cognitive assessment. Ann Intern Med 1987; 107:481-485.

[5.] Levin HS: Neurobehavioral outcome of closed head injury: Implications for clinical trials. J Neurotrauma 1995; 12(4):601-610.

[6.] Osmon DC, Smet IC, Winegarden B, Gandhavadi B: Neurobehavioral Cognitive Status Examination: Its use with unilateral stroke patients in a rehabilitation setting. Arch Phys Med Rehabil 1992; 73:414-418.

[7.] Rowland LP: Pages 3-6, 680-681 in: Merritt's Textbook of Neurology. 1995.

[8.] Schwamm JH, VanDyke C, Kiernan RJ, Merrin EL, Mueller J: The Neurobehavioral Cognitive Status Examination. Part 11: Comparison with the CCSE and MMSE in a neurosurgical population. Ann Intern Med 1987; 107:486-491.

[9.] Terayama Y, Meyer JS, Kawamure J: Cognitive recovery correlates with long-term increases of cerebral perfusion after head injury. Surg Neurol 1991; 36:335-342.

Questions or comments about this article may be directed to: Margarethe Cammermeyer, RN, PhD, CNRN, ARNP, 4632 S.

Tompkins Road, Langley, WA 98260-9695.

Virginia Prendergast, RN, MSN, A GNP is a Nurse Practitioner with Neurosurgical Associates at Barrow Neurological Institute in Phoenix, Arizona.

Copyright [C] American Association of Neuroscience Nurses 0047-2603/96/2903/0163$1.25