Diffusion Imaging of Cerebral Diaschisis in Neonatal Arterial Ischemic Stroke.

BACKGROUND: Neonatal arterial ischemic stroke is a leading cause of cerebral palsy and lifelong disability. Diffusion-weighted imaging has revolutionized diagnosis and facilitated outcome prognostication in acute neonatal arterial ischemic stroke. Diaschisis refers to changes in brain areas functionally connected but structurally remote from primary injury. We hypothesized that acute diffusion-weighted imaging can quantify cerebral diaschisis and is associated with outcome from neonatal arterial ischemic stroke. METHODS: Subjects were identified from a prospective, population-based research cohort (Alberta Perinatal Stroke Project). Inclusion criteria were unilateral middle cerebral artery neonatal arterial ischemic stroke, diffusion-weighted magnetic resonance imaging within 10 days of birth, and more than 12-months follow-up (pediatric stroke outcome measure). Diaschisis was characterized and quantified using a validated software method (ImageJ). Volumetric analysis assessed atrophy of affected structures. Diaschisis scores were corrected for infarct size and compared with outcomes (Mann-Whitney). RESULTS: From 20 eligible neonatal arterial ischemic strokes, two were excluded for poor image quality. Of 18 remaining (61% male, median age 3.2 days), 16 (89%) demonstrated diaschisis. Thalamus (88%) was the most common location in addition to corpus callosum (50%). Age at imaging was not associated with diaschisis. Affected structures demonstrated atrophy on imaging. Long-term outcomes available in 81% (median age 7.5 years) were not associated with diaschisis scores. CONCLUSIONS: Cerebral diaschisis occurs in neonatal arterial ischemic stroke and can be quantified with diffusion-weighted imaging. Occurrence is common and should not be mistaken for additional infarction. Determining clinical significance will require larger samples with well-characterized long-term outcomes.

Aphonogelia After Recovery From Severe Traumatic Brain Injury: A Case Report.

During rehabilitation from a severe traumatic brain injury, a 16-year-old girl became aware that she had lost the ability to laugh out loud. This rare phenomenon previously has been described as "aphonogelia." A discussion of therapeutic avenues that were explored with this patient is presented in the first case, to our knowledge, of aphonogelia after a traumatic brain injury. LEVEL OF EVIDENCE: V.

Magnetic resonance imaging findings of bilateral thalamic involvement in severe paroxysmal sympathetic hyperactivity: a pediatric case series.

PURPOSE: Paroxysmal sympathetic hyperactivity is a complication of brain injury that has mainly been described in the adult brain injury literature. METHODS: We present a case series of three pediatric patients that developed paroxysmal sympathetic hyperactivity of varying severity following hypoxic brain injury. RESULTS: Comparison of brain magnetic resonance imaging revealed bilateral and symmetric global ischemic changes in all three cases. However, the thalamus was not affected in the patient with the mild case of paroxysmal sympathetic hyperactivity. In contrast, bilateral and symmetric damage to the thalamus was observed in the two severe cases. CONCLUSIONS: Our case series suggests that in hypoxic brain injury, evidence of bilateral ischemic injury to the thalamus on magnetic resonance imaging may be an important early predictor of severity and length of paroxysmal sympathetic hyperactivity. While this is an interesting observation, definite proof of our hypothesis requires further research including analysis of larger numbers of patients and comparison of MRI findings in children with hypoxic brain injury that do not develop paroxysmal sympathetic hyperactivity.

Infraslow EEG changes in infantile spasms.

PURPOSE: Infantile spasms (IS) are a devastating epileptic encephalopathy syndrome of infancy. Analysis of infraslow EEG activity (ISA) has shown potential in the presurgical evaluation of patients with epilepsy and in differentiating between focal and generalized epilepsy syndromes. Infraslow EEG activity analysis may provide insights into the pathophysiology of some difficult-to-treat epilepsy syndromes, such as IS. To our knowledge, there are no published reports describing ISA in patients with IS. The purpose of this study was to describe ictal patterns of ISA in patients with IS and to correlate with clinical data. METHODS: EEG recordings of all cases of IS in the past 10 years at the Alberta Children's Hospital were reviewed. Inclusion criteria were a technically adequate video EEG recording that captured at least one spasm. For each patient, the first 10 confirmed spasms were examined. Spasms were evaluated for changes in ISA, which were either generalized, lateralized, or absent ISA (g-ISA, l-ISA, or n-ISA, respectively). Results were correlated with treatments, clinical course, and information pertinent to likely etiology of the IS. RESULTS: A total of 77% of spasms were associated with ISA; 57% with g-ISA, 20% l-ISA, and 21% n-ISA. All patients with exclusively g-ISA showed at least a partial response to initial therapy, while this was the case in 66.7% of those with at least some l-ISA and 50% of those with exclusively n-ISA. Other seizure types occurred in 60% of patients with exclusively g-ISA versus 83% with some l-ISA and all patients with exclusively n-ISA. CONCLUSIONS: Ictal ISA was observed in the majority of IS. Trends were observed suggesting that the presence of exclusive g-ISA changes may be a positive prognostic factor in IS.

Functional asymmetry in human primary auditory cortex: identified from longitudinal fMRI study.

The leftward hemispheric dominance in language processing may be associated with fundamental functional asymmetry in the primary auditory cortex (PAC). Based on repeated functional MRI (fMRI) measurements, we investigated the presence of functional asymmetry in the human PAC using binaural presentation of linguistic sounds (two-syllable nouns) and simple tonal stimulation. Eight right-handed volunteers underwent nine fMRI sessions, approximately eight weeks apart, spanning the duration of more than a year. The PAC from each hemisphere was manually segmented and the volume of activation, detected within the segmented region-of-interest, was measured across the subjects and sessions to generate functional laterality indices. Although variations existed in activation volume between sessions and subjects, we found predominant and consistent leftward functional asymmetry in PAC during both linguistic and non-linguistic sound stimulations.