Objective: We developed a computerized assessment tool for validation in screening cognitive competency for locked-in patients. The clinical problem is that some locked-in patients (eg. people with ALS) may have difficult to measure cognitive deficits when their response capabilities are severely language or motor impaired.
Method: Our program assesses twenty-four areas of cognitive functioning in attention, language, memory, visual spatial and executive functioning. A technique is used where answers to questions are highlighted by a strobe and a selection is made by a simple motor response (eg. a tap on the computer mouse, or in the future an eye-blinking response). We tested a dementia group, an age matched control group and a student control group.
Results: Using a multivariate anova comparing the three groups, significant differences were found in almost all categories. On one category there were no differences between the three groups, but the test will be kept as a measure of effort. Another category showed no difference between the groups because there was only one question. In Bonferroni post-hoc analyses comparing each group, the demented group performed significantly worse than either control group.
Conclusion: These results confirm that the assessment tool is valid in differentiating between normal and impaired cognitive functioning. The plan is to reduce the length of the test, create cutoff scores for normal cognitive functioning, and create a profile for use with locked-in patients.
The cognitive impairments seen in ALS could cognitively match Dementia. If we use dementia patients as the impaired group, we can first see if the test can differentiate between normal and impaired cognitive functioning.
If the test proves valid, it can be administered to ALS patients, to see which pattern they follow; normal, impaired, or their own.
The SLIP test will differentiate between normal and impaired cognitive functioning, by the demented group having more incorrect responses than the normal group.
Twenty-eight (13 male, 15 female) age-matched normal cognitive functioning individuals ranging in age from 28 to 79.
Sixty-one normal cognitive functioning college-aged students were also tested.
Quality of life: orientation, general health and severity of ALS
To compensate for motor and speech impairment, a strobing technique highlights each answer choice and the subject uses a mouse click to respond.
The software is self-narrated for easier use and better reliability, although an experimenter is present for assistance.
Multivariate ANOVA comparing the three groups:
Language: reading-word identification, reading-sentence completion,naming, matching pictures to phrases, complex comprehension
No significant differences were found on the following tests:
Language: matching shapes to phrases (p=.767)
Post-Hoc Analyses (With Bonferonni Correction):
The demented group performed significantly worse than the age-matched and student controls in the following categories: p<.05
Language: reading-word identification, naming, matching-pictures to phrases, complex comprehension
The demented group performed significantly worse than the students, but not the age-matched control group:
Language: reading-sentence completion (p=.821)
The demented group performed significantly worse than the age-matched control group, but not the student control group:
Memory: remote memory (p=1)
These results mean that the SLIP can differentiate between normal and impaired cognitive functioning.
Tests that did not show a significant difference between the impaired and non-impaired groups were due to either not enough questions within the test or the dementia group performing well. These tests will be revised or excluded from the program.
In order to obtain more reliable and valid results, approximately twenty more dementia patients will be tested.
Cut-off scores will be established for normal and impaired cognitive functioning.
If the test is still valid, an ALS group will be tested to understand their cognitive functioning.