Screening mental status in adults with aphasia using a language-modified form of the Mini-Mental State Examination: a preliminary investigation. Journal of Medical Speech – Language Pathology | March 01, 2008 | Pashek, Gail V.
Screening for dementia in individuals with preexisting cognitive problems presents a special diagnostic dilemma for clinicians working with geriatric patients. In particular, patients with language deficits such as stroke-related aphasia present a special challenge because of the unsuitability of most cognitive measures for this population. Neuropsychological batteries employed in cognitive assessment generally are heavily dependent on language abilities, both in instructions and response expectations, making them inappropriate for most individuals with limited language abilities.
Unfortunately, individuals with stroke are at greater risk for dementia. After the primary medical disorder associated with dementia, Alzheimer’s disease (AD), a common etiology is vascular dementia (VaD). Vascular dementia is often associated with large-vessel, deep subcortical (lacunar) strokes, or subcortical arteriosclerotic encephalopathy (Roman et al., 1993). Also, risk factors associated with stroke, such as cardiac disease, elevated serum cholesterol, hypertension, diabetes, and smoking, or the presence of underlying autoimmune disorders (e.g., lupus) or infectious vasculitis (e.g, neurosyphyllis) also place stroke survivors at higher risk for additional brain damage (Cohen & Eisdorfer, 1984; Elkins et al., 2004; in’t Veld, Ruitenberg, Hofman, Stricker & Breteler, 2001; Roman et al., 1993). In addition, research also suggests that mixed dementia, in which patients present with signs of both vascular and Alzheimer’s pathologies, is also fairly common, particularly in individuals over age 65. Leys, Henon, Mackowiak-Cordoliani, and Pasquier (2005) report that estimates of dementia of any kind following stroke range from 17 to 30%, varying on the basis of criteria employed in studies.
Diagnosing additional cognitive decline in stroke-related aphasia is important for several reasons. First, the onset of cognitive-language changes in an individual with diagnosed or undiagnosed vascular disorders, appearing with either sudden or gradual onset, is a sign that medical evaluation is needed. Progressive vascular disorders may, in some cases, be arrested and/or partially reversed (Mandava & Kent, 2005). Symptoms of dementia may be mitigated by a number of pharmacological agents, such as cholinesterase inhibitors and/or memantine, an agent that blocks NMDA receptors. Second, the diagnosis of a progressive medical disorder associated with dementia also has major implications for changes in life that impact not only the affected individual, but others in that person’s family, work, and social circles. Second, possible misdiagnosis of individuals with stroke and aphasia as “demented” has far-reaching, personal and legal implications that may negatively impact one’s life. Individuals with stroke-related aphasia are often well oriented and independent in many aspects of life; a misdiagnosis of dementia may render them formally or informally incompetent in the eyes of their peers and society.
The desire for a brief cognitive screening measure as one tool to assess for dementia that is suitable for use by professionals in a variety of disciplines has spawned a wide variety of brief cognitive tests most of which, alas, are highly language dependent. These include the Blessed Orientation and Memory Examination (Blessed, Tomlinson, & Roth, 1968), Mental Status Questionnaire (MSQ; Goldfarb, 1975; Kahn, Goldfarb, Pollack, & Peck, 1960), Mini-Mental State Examination (MMSE; [Folstein, Robins, & Helzer, 1983], originally the Mini-Mental State [MMSE; Folstein, Folstein & McHugh, 1975]), Short Portable Mental Status Exam (Pfieiffer, 1975), the 7 Minute Screen (Solomon & Pendlebury, 1998). The most widely used of these measures is the MMSE and its many derived forms.
Few investigators have directly attempted to address the task of developing a valid mental status measure specifically for individuals with language limitations or impairments (Golper, Rau, Erskine, Langhans, & Houlihan, 1987; Hobson, Leeds, & Meara, 2003; Sanchez, Grober, & Birkett, 1997). Golper et al. demonstrated that individuals with aphasia who behaviorally demonstrate intact or nearly intact nonlanguage cognitive skills scored comparably to individuals with dementia on the MMSE. Golper et al. concluded that such mental status tests were invalid for individuals with focal cortical damage, citing a concern that health care professionals inexperienced with language-impaired adults may misinterpret the low scores of individuals with aphasia.
Clearly, there is a need to develop measures of mental status that rely less on language abilities while still retaining sensitivity to distinguish among healthy aging, demented, and aphasic individuals who have sustained focal lesions. Recently, several investigators have suggested alternative measures for this purpose (Hobson et al., 2003; Sanchez et al., 1997). Sanchez et al. explored the utility of a spatial location test plus the MSQ in two groups: (a) geriatric psychiatric inpatients with a variety of disorders (“controls”), and (b) patients within residential institutions referred for psychiatric evaluation who were believed to have left brain damage. Although Sanchez et al. present data supporting the use of their selected measures to distinguish between left-brain-damaged adults and their comparison sample, it is unclear to what extent the left-brain-damaged participants were aphasic and what concomitant disorders these adults may have had that precipitated psychiatric referral, since neither concern was mentioned in the article. Hobson et al. (2003) suggested cognitive screening with a brief battery designed for traumatically brain-injured patients employing “yes” or “no” responses to questions (Cossa, Fabiani, Farinato, Laiacona, & Capitani, 1999). Performance in a sample of consecutive hospital stroke admissions (N = 149) and controls (N = 120) was described. However, Hobson et al. excluded patients with “significant” speech and language difficulties, and no language assessment data are provided. The measures proposed by Sanchez and Hobson may have promise for future research on cognitive screening of individuals with aphasia, but clarification and greater specification of subject inclusion and exclusion criteria are required.
Alternately, a logical starting point for developing a test modified to be sensitive to language limitations is the MMSE, as it is well established and familiar to professionals from a variety of disciplines. Although the MMSE has demonstrated limitations, particularly in its lack of sensitivity to mild and early cases of dementia, and oversensitivity to educational and age differences in individuals (Tombaugh & McIntyre, 1992), it remains among the most frequently used brief cognitive screening measures, with demonstrated criterion validity and test-retest reliability (Brayne, 1998; Stuss, Meiran, Guzman, Lafleche, & Willmer, 1996). In the present study, an adapted version of the MMSE designed to decrease language demands (LMMS) was piloted as part of a larger research program designed to examine and compare the cognitive performance of adults with acquired language deficits resulting from stroke and individuals with dementia on a variety of measures. As one project in this program, this study was designed to determine whether a language-modified version of the MMSE could be developed with acceptable levels of validity and reliability and whether performance of normal older adults, individuals with stroke-related aphasia, and persons with AD could be differentiated with this measure.
