Brain glucose metabolic changes associated with chronic spontaneous pain due to brachial plexus avulsion: a preliminary positron emission tomography study:

Effect of traumatic upper-limb injury on cognitive functions: A cross-sectional observational study

OBJECTIVES

There is growing evidence of cognitive impairment after traumatic peripheral lesions. The purpose of this study was to explore the association between cognitive function and traumatic upper-limb injury. We assessed difference in cognitive function between participants with and without upper-limb injury, and explored the association between cognitive function and certain variables in injured individuals: gender, age, body mass index (BMI), educational level, and occupation. We sought to identify the factors associated with cognitive function in injured subjects: time since injury, injury side, nerve injury, hand function, pain, and finger sensation.

MATERIAL AND METHODS

A cross-sectional observational study was conducted, with 2 groups: observational group (with traumatic upper-limb injury) and control group (uninjured). The 2 groups were matched for age, gender, BMI, educational level and occupation. Short-term memory and executive functions were assessed using the Rey Auditory and Verbal Learning Test (RAVLT) and Stroop Color and Word Test (SCWT), respectively.

RESULTS

104 participants with traumatic upper-limb injury and 104 uninjured control subjects were included. There was a significant inter-group difference only in RAVLT (p < 0.01; Cohen d, of 0.38). Regression analysis demonstrated an association of pain on VAS (beta = -0.16, p < 0.01) and touch-test (beta = 1.09, p < 0.05) with total RAVLT score (short-term memory) in injured subjects (R2 = 0.19, F (2, 82) = 9.54, p < 0.001).

CONCLUSION

Traumatic upper-limb injury can impact short-term memory, which should be kept in mind during rehabilitation.

Brodmann area 10: Collating, integrating and high level processing of nociception and pain

Multiple frontal cortical brain regions have emerged as being important in pain processing, whether it be integrative, sensory, cognitive, or emotional. One such region, Brodmann Area 10 (BA 10), is the largest frontal brain region that has been shown to be involved in a wide variety of functions including risk and decision making, odor evaluation, reward and conflict, pain, and working memory. BA 10, also known as the anterior prefrontal cortex, frontopolar prefrontal cortex or rostral prefrontal cortex, is comprised of at least two cytoarchitectonic sub-regions, medial and lateral. To date, the explicit role of BA 10 in the processing of pain hasn't been fully elucidated. In this paper, we first review the anatomical pathways and functional connectivity of BA 10. Numerous functional imaging studies of experimental or clinical pain have also reported brain activations and/or deactivations in BA 10 in response to painful events. The evidence suggests that BA 10 may play a critical role in the collation, integration and high-level processing of nociception and pain, but also reveals possible functional distinctions between the subregions of BA 10 in this process.

Vascular dementia with left thalamic infarction: neuropsychological and behavioral implications suggested by involvement of the thalamic nucleus and the remote effect on cerebral cortex. The Osaki-Tajiri project

Vascular dementia (VaD) is a condition whereby decreased cerebral perfusion causes cognitive deterioration. We hypothesized that lesions of the anterior nucleus (AN) including the mammillo-thalamic tract cause a decline in the recollection of past episodes/events, and that the left thalamic infarction can cause frontal dysfunction through the "diaschisis." We investigated 18 VaD cases with only left thalamic infarction. (99m)Tc-ECD single photon emission computed tomography (SPECT) was used to assess regional cerebral blood flow (CBF). To test the first hypothesis, the scores on the Cognitive Abilities Screening Instrument (CASI) domain Recent memory or the rating on the Clinical Dementia Rating (CDR) domain Memory were analyzed. To test the second hypothesis, we selected the six regions of interest that correlated with the two measures, i.e., word fluency and/or depressive state, as assessed with the Geriatric Depression Scale (GDS). We found that all patients had amnesia, especially in the AN group, six of the eight patients had scores of 1+ on the CDR Memory scale, and all but one disclosed the CASI domain Recent memory impairment. There were significant correlations between the left anterior cingulate CBF and word fluency scores, and between the right rectal gyrus CBF and GDS scores. We suggest that these observations are due to a remote effect of the thalamic lesion.