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1.  Cognitive deficits following exposure to pneumococcal meningitis: an event-related potential study 
Pneumococcal meningitis (PM) is a severe and life-threatening disease that is associated with cognitive impairment including learning difficulties, cognitive slowness, short-term memory deficits and poor academic performance. There are limited data on cognitive outcomes following exposure to PM from Africa mainly due to lack of culturally appropriate tools. We report cognitive processes of exposed children as measured by auditory and visual event-related potentials.
Sixty-five children (32 male, mean 8.4 years, SD 3.0 years) aged between 4-15 years with a history of PM and an age-matched control group of 93 children (46 male; mean 8.4 years, SD 2.7 years) were recruited from a well-demarcated study area in Kilifi. In the present study, both baseline to peak and peak-to-peak amplitude differences are reported.
Children with a history of pneumococcal meningitis had significantly longer auditory P1 and P3a latencies and smaller P1 amplitudes compared to unexposed children. In the visual paradigm, children with PM seemingly lacked a novelty P3a component around 350 ms where control children had a maximum, and showed a lack of stimulus differentiation at Nc. Further, children with exposure to PM had smaller peak to peak amplitude (N2-P1) compared to unexposed children.
The results suggest that children with a history of PM process novelty differently than do unexposed children, with slower latencies and reduced or absent components. This pattern suggests poorer auditory attention and/or cognitive slowness and poorer visual attention orienting, possibly due to disruption in the functions of the lateral prefrontal and superior temporal cortices. ERPs may be useful for assessment of the development of perceptual-cognitive functions in post brain-injury in African children by providing an alternate way of assessing cognitive development in patient groups for whom more typical standardized neuropsychological assessments are unavailable.
PMCID: PMC3347992  PMID: 22462525
2.  Atypical brain response to novelty in rural African children with a history of severe falciparum malaria 
Plasmodium falciparum is the most common parasitic infection of the central nervous system causing neuro-cognitive deficits in 5–26% of paediatric cases. The burden cannot be reliably estimated because of lack of sensitive, culture-fair and robust assessments in rural settings. Auditory and visual brain event related potentials (ERPs) are used to compare novelty processing in children exposed to severe malaria with community controls. Fifty children previously admitted and discharged from Kilifi District Hospital with severe falciparum malaria were selected and compared with 77 unexposed agematched children. The results showed that up to 14% of children exposed to severe malaria had significantly different responses to novelty compared to unexposed children. Children exposed to severe malaria had smaller P3a amplitudes to novelty in both auditory [F (3, 119) = 4.545, p = 0.005] and visual [F (3, 119) = 6.708, p < 0.001] paradigms compared to unexposed children. In the auditory domain the differences in processing of novelty were not related to early component processing. The percentage of children with severe malaria showing impaired performance using ERPs is within the range previously reported using neuropsychological tests. The overall pattern suggests that severe malaria affects prefrontal and temporal cortices normally activated by stimulus novelty.
PMCID: PMC2923746  PMID: 20566207
Severe falciparum malaria; Event-related potentials; Cognitive; Children
3.  Auditory and visual novelty processing in normally-developing Kenyan children 
Clinical Neurophysiology  2010;121(4):564-576.
The aim of this study was to describe the normative development of the electrophysiological response to auditory and visual novelty in children living in rural Kenya.
We examined event-related potentials (ERPs) elicited by novel auditory and visual stimuli in 178 normally-developing children aged 4–12 years (86 boys, mean 6.7 years, SD 1.8 years and 92 girls, mean 6.6 years, SD 1.5 years) who were living in rural Kenya.
The latency of early components (auditory P1 and visual N170) decreased with age and their amplitudes also tended to decrease with age. The changes in longer-latency components (Auditory N2, P3a and visual Nc, P3a) were more modality-specific; the N2 amplitude to novel stimuli decreased with age and the auditory P3a increased in both latency and amplitude with age. The Nc amplitude decreased with age while visual P3a amplitude tended to increase, though not linearly.
The changes in the timing and magnitude of early-latency ERPs likely reflect brain maturational processes. The age-related changes to auditory stimuli generally occurred later than those to visual stimuli suggesting that visual processing matures faster than auditory processing.
ERPs may be used to assess children’s cognitive development in rural areas of Africa.
PMCID: PMC2842935  PMID: 20080442
Event-related potentials; Normative data; Novelty processing; Children; Africa
4.  Continuous EEG monitoring in Kenyan children with non-traumatic coma 
Archives of Disease in Childhood  2012;97(4):343-349.
The aim of this study was to describe the EEG and clinical profile of seizures in children with non-traumatic coma, compare seizure detection by clinical observations with that by continuous EEG, and relate EEG features to outcome.
This prospective observational study was conducted at the paediatric high dependency unit of Kilifi District Hospital, Kenya. Children aged 9 months to 13 years presenting with acute coma were monitored by EEG for 72 h or until they regained consciousness or died. Poor outcome was defined as death or gross motor deficits at discharge.
82 children (median age 2.8 (IQR 2.0–3.9) years) were recruited. An initial medium EEG amplitude (100–300 mV) was associated with less risk of poor outcome compared to low amplitude (≤100 mV) (OR 0.2, 95% CI 0.1 to 0.7; p<0.01). 363 seizures in 28 (34%) children were observed: 240 (66%) were electrographic and 112 (31%) electroclinical. In 16 (20%) children, electrographic seizures were the only seizure types detected. The majority (63%) of electroclinical seizures had focal clinical features but appeared as generalised (79%) or focal with secondary generalisation (14%) on EEG. Occurrence of any seizure or status epilepticus during monitoring was associated with poor outcome (OR 3.2, 95% CI 1.2 to 8.7; p=0.02 and OR 4.5, 95% CI 1.3 to 15.3; p<0.01, respectively).
Initial EEG background amplitude is prognostic in paediatric non-traumatic coma. Clinical observations do not detect two out of three seizures. Seizures and status epilepticus after admission are associated with poor outcome.
PMCID: PMC3329232  PMID: 22328741

Results 1-4 (4)