Understanding the association between psychomotor processing speed and white matter hyperintensity: A comprehensive...

Area of Science:

• Neuroscience
• Gerontology
• Radiology

Background:

• Cognitive processing speed declines with aging, impacting daily function.
• White matter hyperintensity (WMH) is a common age-related marker of cerebrovascular damage.
• WMH is associated with slower psychomotor processing speed in the elderly.

Purpose of the Study:

• To investigate the association between WMH and psychomotor speed changes.
• To explore the roles of brain structure (WMH, white matter integrity) and function (brain activity) in psychomotor speed decline.
• To comprehensively assess elderly adults using multi-modal MRI and behavioral tests.

Main Methods:

• Acquired multi-modal MRI data from 60 elderly adults.
• Assessed psychomotor processing speed using the Trail Making Test Part A (TMT-A).
• Performed linear and hierarchical regression analyses correlating TMT-A with WMH volume, white matter diffusivity (fractional anisotropy), gray matter volume, and resting-state brain activity.

Main Results:

• WMH volume in the occipital lobe was associated with slower TMT-A performance.
• Reduced fractional anisotropy in the forceps major (occipital association tract) correlated with TMT-A.
• Altered resting-state brain activity in the visual cortex, connected by the forceps major, was also linked to TMT-A.

Conclusions:

• WMH, disrupted white matter tract integrity (forceps major), and altered functional brain activity in connected regions contribute to age-related decline in psychomotor processing speed.
• This study highlights a complex link between white matter lesions, tract integrity, brain function, and behavior.
• Further research is needed to establish the causal relationships within this WMH-Tract-Function-Behavior pathway.