The relationship between executive functioning, processing speed, and white matter integrity in multiple sclerosis

Abstract

The primary purpose of the current study was to examine the relationship between performance on executive tasks and white matter integrity, assessed by diffusion tensor imaging (DTI) in Multiple Sclerosis (MS). A second aim was to examine how processing speed affects the relationship between executive functioning and FA. This relationship was examined in two executive tasks that rely heavily on processing speed: the Color-Word Interference Test and Trail-Making Test (Delis-Kaplan Executive Function System). It was hypothesized that reduced fractional anisotropy (FA) is related to poor performance on executive tasks in MS, but that this relationship would be affected by the statistical correction of processing speed from the executive tasks. 15 healthy controls and 25 persons with MS participated. Regression analyses were used to examine the relationship between executive functioning and FA, both before and after processing speed was removed from the executive scores. Before processing speed was removed from the executive scores, reduced FA was associated with poor performance on Color-Word Interference Test and Trail-Making Test in a diffuse network including corpus callosum and superior longitudinal fasciculus. However, once processing speed was removed, the relationship between executive functions and FA was no longer significant on the Trail Making test, and significantly reduced and more localized on the Color-Word Interference Test.

Perfusion shift from white to gray matter may account for processing speed deficits in schizophrenia

“…The analysis of regional trends further corroborated our hypothesis by demonstrating that reduced integrity of associative, rather than motor and sensory, WM regions may explain the processing speed deficits in both groups. This is consistent with previous research showing that the integrity of associative WM fibers that carry multimodal, higher order functional information, is critical for maintaining normal speed of information processing [Borghesani et al, ; Genova et al, ; Kochunov et al, ; Llufriu et al, ; Peters et al, ]. R WM/GM appeared to be specifically associated with processing speed.…”

Neuroimaging of corpus callosum in central nervous system demyelinating disorders

“…[29][30][31][32][33] Sigal et al [11] used DTI to investigate CC integrity in MS patients and age matched controls. In agreement with other studies, [15,26,28,31] MS patients had significant reduction in CC 's FA compared with control group in all subregion of CC, indicating axonal loss and dysfunction in callosal fibers. Most recent studies agree on the fact that in MS patients all MRI indices and parameters are altered pathologically especially in the CC structure.…”

“…There are also some other parameters in the matter of directional diffusivity such as: radial and axial diffusivity, which have been used by many recent studies. [15,25,26,28] Such parameters interestingly found to be helpful in detecting microscopic and structural changes in lesional and NAWM. Most of recent studies showed increased ADC and reduced FA in both pathologic and NAWM.…”

“…[7][8][9][10][11] In this article, we review different aspects of imaging and involvement patterns of CC in various CNS demyelinating disorders to determine more helpful ways of discrimination of such diseases and also, to demonstrate the role of white matter lesions (particularly in CC) in evaluation of prognosis of these demyelinating disorders. [12][13][14][15][16] To our knowledge there was no article previously, discussing and comparing CC features in different CNS demyelinating disorders similar to ours.…”

Cortical morphometry and structural connectivity relate to executive function and estradiol level in healthy adolescents

“…White matter results indicated decreases in EF behavior relating to putting order into work and play (Plan/Organize subscale) was associated with decreased FA in the forceps minor. Research demonstrates the forceps minor is a fiber bundle which connects the lateral and medial surfaces of the frontal lobes and crosses the midline via the genu of the corpus callosum (Genova, DeLuca, Chiaravalloti, & Wylie, ). When damaged by disease, the forceps minor is linked to robustly diminished processing speed and cognitive impairment, indicating its interhemispheric connections between the PFC contribute to EF (Biesbroek et al, ; Genova et al, ).…”