Correlation of magnetic resonance imaging with neuropsychological testing in multiple sclerosis

Abstract

Article abstract-Previous research has suggested that cerebral lesions observed on magnetic resonance imaging (MRI) of MS patients are clinically "silent." We examined the validity of this assertion by correlating neuropsychological test performance with MRI findings in 53 MS patients. We used a semiautomated quantitation system to measure three MRI variables: total lesion area (TLA), ventricular-brain ratio (VBR) Magnetic resonance imaging (MRI) is extremely sensitive for the detection of focal areas of demyelination in patients with MS.lv2 The clinical significance of these lesions remains unclear. Their correlation with neurologic symptoms and degree of disability has been uniformly disappointing,3-6 prompting the view that MS lesions occur in brain regions that are clinically "silent." Others7v8 have recommended the use of neuropsychological testing to evaluate the possible relationship between cerebral demyelination and cognitive dysfunction.Two studiesgJO attempted to relate cognitive dysfunction to lesions identified by MRI. Franklin et a19 examined 60 patients with chronic progressive MS and found a significant correlation (r = 0.35) between an overall brain lesion score and a summary score derived from a brief cognitive screening battery. Huber et all0 administered a brief battery of neuropsychological tests to 30 MS patients, nine of whom were classified as "demented," 11 moderately cognitively impaired, and 12 minimally impaired. These investigators observed no significant group differences on three MRI indexes: total lesion score, cerebral atrophy, and severity of periventricular involvement. On the fourth index, atrophy of the corpus callosum, the "demented" patients had significantly higher ratings than the moderate and minimal cognitive impairment groups. These two studies found significant correlations between MRI variables and cognitive testing, yet the strength of the correlations was modest. Three methodologic factors may have contributed to their limited success in obtaining meaningful correlations. First, both studies relied on rating scales to measure the size of lesions from MRIs. Rating scales by definition are subjective and prone to human error. In addition, rating scales provide a more restricted range of data values than quantitative systems that measure lesions in area units; this restricted range may seriously limit the size of obtained correlations. Second, both studies used brief cognitive screening examinations. MS does not produce a uniform decline of all cognitive skills7J1; although these brief batteries covered a number of cognitive functions, they may have missed salient cognitive deficits. A more comprehensive neuropsychological examination may be more successful in measuring those cognitive functions that are influenced by MS-related cerebral pathology. Finally, cognitive test performance is affected by education and age.12 Thus, relatively uneducated or older patients may be classified as impaired on testing when they are functioning close to their premorbid level. Conver...

Cognitive clinico‐radiological paradox in early stages of multiple sclerosis

“…Particularly, T1 lesion volume (T1‐LV) and T2 lesion volume (T2‐LV),8, 9 damage of normal‐appearing white matter,10, 11 occurrence of cortical lesions,12, 13 and gray matter,14, 15 or thalamic atrophy11, 16 have been suggested as important brain imaging correlates of cognitive impairment.…”

Patterns of Cognitive Impairment in Secondary Progressive Stable Phase of Multiple Sclerosis: Correlations with MRI Findings

“…Neuropsychological assessment in MS patients has received growing attention in the last years, in order to better define the prevalence of cognitive dysfunction, to explore its nature and to find the correlates of these deficits with clinical and neuroradiological features [1, 2, 3, 4, 18, 19]. …”

“…The random occurrence of MS lesions, both in space and time, accounts for the extreme variability of clinical presentation. Although motor disorders have the greatest influence on the evaluation of disability, as measured by the scales widely used for the staging of MS patients, cognitive deficits are emerging as the main cause of changes in professional and social life [1, 2, 3, 4]. In fact, cognition is the neurological function which can be most strongly influenced by the accumulation of demyelinating lesions in the brain.…”

“…However, even if it is not easy to reach an absolute methodological equality, a series of studies [2, 9, 10, 11]have at least marked the boundaries of neuropsychological evaluation.…”

“…On the other hand, several studies have demonstrated a significant correlation between the global cognitive impairment and the severity of magnetic resonance imaging (MRI) findings, such as white matter abnormalities of the hemispheres, corpus callosum atrophy and ventricular dilatation [2, 9, 10, 11, 12, 13, 14]. Furthermore, some specifically addressed studies have shown correlations between MRI indexes and performances in some cognitive domains, especially in the so-called frontal lobe functions [15].…”