Differences in vulnerability between the hemispheres in early childhood and adulthood

Njiokiktjien, C

doi:10.1134/s0362119706010051

Cited by 18 publications

(21 citation statements)

References 58 publications

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“…Asymmetrical injury to WM in the watershed areas shows a very high correlation with cerebrovascular insufficiency . In addition, it has been suggested that the left hemisphere may be more vulnerable than the right to detrimental influences, including hypoxia . In our study sample, all of the 29 participants were right‐handed, which may also be a contributing factor to the observed asymmetry.…”

Section: Discussionmentioning

confidence: 82%

Brain white matter changes in CPAP‐treated obstructive sleep apnea patients with residual sleepiness

Xiong

Zhou

Nisi

et al. 2016

Magnetic Resonance Imaging

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Purpose To investigate white matter (WM) structural alterations using diffusion tensor imaging (DTI) in obstructive sleep apnea (OSA) patients, with or without residual sleepiness, following adherent continuous positive airway pressure (CPAP) treatment. Possible quantitative relationships were explored between the DTI metrics and two clinical assessments of somnolence. Methods Twenty nine male patients (30–55 years old) with a confirmed diagnosis of OSA were recruited. The patients were treated with CPAP therapy only. The Psychomotor Vigilance Task (PVT) and Epworth Sleepiness Scale (ESS) were performed after CPAP treatment and additionally administered at the time of MRI scan. Based on the PVT results, the patients were divided into a non-sleepy group (lapses≤5) and a sleepy group (lapses > 5). DTI was performed at 3T, followed by an analysis using tract-based spatial statistics (TBSS) to investigate the differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ1), and radial diffusivity (λ23) between the two groups. Results A higher MD (p < 0.05) was observed in the sleepy group than the non-sleepy group in the whole-brain TBSS analysis in the WM. The increased MD (17.8% of the fiber tracts; p<0.05) was caused primarily by an elevated λ23. Axial diffusivity (λ1) exhibited no significant difference (p > 0.17). The alterations in FA or MD of individual fiber tracts occurred mainly in the internal/external capsule, corona radiata, corpus callosum, and sagittal stratum regions. The FA and MD values correlated with the PVT and ESS assessments from all patients (R ≥ 0.517, p < 0.05). Conclusions Global and regional WM alterations, as revealed by DTI, can be a possible mechanism to explain why OSA patients with high levels of CPAP use can have differing responses to treatment. Compromised myelin sheath, indicated by increased radial diffusivity, can be involved in the underlying WM changes.

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Section: Discussionmentioning

confidence: 82%

Brain white matter changes in CPAP‐treated obstructive sleep apnea patients with residual sleepiness

Xiong

Zhou

Nisi

et al. 2016

Magnetic Resonance Imaging

View full text Add to dashboard Cite

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“…However, increased left hemisphere susceptibility has been consistently noted in several other neurological conditions. Potential reasons for this preferential vulnerability include asymmetry in hemodynamics and developmental trajectory (Njiokiktjien, 2006). The language-dominant hemisphere tends to be more highly connected (Parker et al, 2005) which is associated with greater energy demands (Lord et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Atypical Structural Connectome Organization and Cognitive Impairment in Young Survivors of Acute Lymphoblastic Leukemia

et al. 2016

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Survivors of pediatric acute lymphoblastic leukemia (ALL) are at increased risk for cognitive impairments that disrupt everyday functioning and decrease quality of life. The specific biological mechanisms underlying cognitive impairment following ALL remain largely unclear, but previous studies consistently demonstrate significant white matter pathology. We aimed to extend this literature by examining the organization of the white matter connectome in young patients with a history of ALL treated with chemotherapy only. We applied graph theoretical analysis to diffusion tensor imaging obtained from 31 survivors of ALL age 5-19 years and 39 matched healthy controls. Results indicated significantly lower small-worldness ( p = 0.007) and network clustering coefficient ( p = 0.019), as well as greater cognitive impairment ( p = 0.027) in the ALL group. Regional analysis indicated that clustered connectivity in parietal, frontal, hippocampal, amygdalar, thalamic, and occipital regions was altered in the ALL group. Random forest analysis revealed a model of connectome and demographic variables that could automatically classify survivors of ALL as having cognitive impairment or not (accuracy = 0.89, p < 0.0001). These findings provide further evidence of brain injury in young survivors of ALL, even those without a history of central nervous system (CNS) disease or cranial radiation. Efficiency of local information processing, reorganization of hub connectivity, and cognitive reserve may contribute to cognitive outcome in these children. Certain connectome properties showed U-shaped relationships with cognitive impairment suggesting an optimal range of regional connectivity.

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“…Past studies point to multiple factors that may result in a greater vulnerability of the left hemisphere to various developmental insults (Njiokiktjien, 2006). It was postulated that the left hemisphere is immature at birth and then undergoes a rapid, but prolonged maturation process, rendering it more vulnerable (especially the white matter) to early brain insults (Corballis & Morgan, 1978).…”

Section: Discussionmentioning

confidence: 99%

“…Potentially more intricate connections of the hippocampus with the rest of the brain in the dominant hemisphere can give rise to more excitotoxic damage from seizures, or to more neuronal loss from deafferentation secondary to hippocampal atrophy (Bonilha et al., 2007; Coan et al., 2009). Furthermore, vascular differences in blood perfusion to the left versus right hemisphere may result in more frequent and extreme damage to the left hemisphere in both children and adults (Njiokiktjien, 2006). Together, these studies suggest that patients with LTLE are more susceptible to bilateral neocortical atrophy resulting from refractory seizures, and that this pattern may be accentuated in their more vulnerable, ipsilateral hemisphere.…”

Section: Discussionmentioning

confidence: 99%

MRI analysis in temporal lobe epilepsy: Cortical thinning and white matter disruptions are related to side of seizure onset

et al. 2011

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Summary Purpose Past studies reported more widespread structural brain abnormalities in patients with left compared to right temporal lobe epilepsy (TLE), but the profile of these differences remain unknown. This study investigated the relationship between cortical thinning, white matter compromise, epilepsy variables, and the side of seizure onset, in patients with TLE. Methods We performed diffusion tensor imaging tractography and cortical thickness analyses of 18 patients with left TLE (LTLE), 18 patients with right TLE (RTLE), and 36 controls. We investigated the relationship between brain structural abnormalities, side of seizure onset, age of seizure onset, and disease duration. Key findings TLE groups displayed cortical thinning and white matter compromise, predominately on the side ipsilateral to the seizure onset. Relative to RTLE, patients with LTLE showed more widespread abnormalities, particularly in white matter fiber tracts. Greater compromise in white matter integrity was associated with earlier age of seizure onset, while cortical thinning was marginally associated with disease duration. Significance These data support previous findings of LTLE showing greater structural compromise than RTLE, and suggest that mechanisms may not be uniform for gray and white matter compromise in patients with LTLE and RTLE. These results may indicate that LTLE is different than RTLE, possibly due to greater vulnerability of the left hemisphere to early injury and the progressive effects of seizures.

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Differences in vulnerability between the hemispheres in early childhood and adulthood

Cited by 18 publications

References 58 publications

Brain white matter changes in CPAP‐treated obstructive sleep apnea patients with residual sleepiness

Brain white matter changes in CPAP‐treated obstructive sleep apnea patients with residual sleepiness

Atypical Structural Connectome Organization and Cognitive Impairment in Young Survivors of Acute Lymphoblastic Leukemia

MRI analysis in temporal lobe epilepsy: Cortical thinning and white matter disruptions are related to side of seizure onset

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