Continous somatosensory evoked potentials and brain injury in neonatal hypoxic-ischaemic encephalopathy treated with hypothermia.

AIM: To explore whether continuous somatosensory evoked potentials (SEPs) monitoring and video electroencephalograms (VEEG) accurately predict lesions observed on brain magnetic resonance imaging (MRI) in neonates with hypoxic-ischaemic encephalopathy (HIE) receiving therapeutic hypothermia. METHOD: This prospective study included 31 neonates (16 males, 15 females; mean [SD] gestational age 39 weeks [1.67]) who received therapeutic hypothermia for HIE. Therapeutic hypothermia was provided for 72 hours, with a target temperature of 33.0°C to 34.0°C and this was followed by a rewarming rate of approximately 0.5°C per hour, up to 36.5°C. SEPs and VEEG were evaluated simultaneously and continuously for 1 hour under normothermic conditions. MRI was carried out at a mean (SD) age of 6 (2) days. RESULTS: Our results showed a statistically significant correlation between continuous SEP and MRI scores (r=0.37, p=0.03), but not between the VEEG and MRI scores (r=0.30, p=0.09). Receiver operating characteristic analysis confirmed that continuous SEPs were highly specific and sensitive at predicting MRI abnormalities, whereas the VEEG had high specificity but low sensitivity. INTERPRETATION: Continuous monitoring of SEPs could provide early and important prognostic information in neonates with HIE. WHAT THIS PAPER ADDS: Early continuous somatosensory evoked potential (SEP) monitoring is correlated with hypoxic-ischaemic encephalopathy (HIE) lesions. Video electroencephalograms (VEEGs) are associated with lesions diagnosed after magnetic resonance imaging. Both showed high specificity, but VEEGs did not show high sensitivity. Continuously monitoring SEPs provides important information about HIE.

Asymmetry in sleep spindles and motor outcome in infants with unilateral brain injury.

AIM: To determine whether interhemispheric difference in sleep spindles in infants with perinatal unilateral brain injury could link to a pathological network reorganization that underpins the development of unilateral cerebral palsy (CP). METHOD: This was a multicentre retrospective study of 40 infants (19 females, 21 males) with unilateral brain injury. Sleep spindles were detected and quantified with an automated algorithm from electroencephalograph records performed at 2 months to 5 months of age. The clinical outcomes after 18 months were compared to spindle power asymmetry (SPA) between hemispheres in different brain regions. RESULTS: We found a significantly increased SPA in infants who later developed unilateral CP (n=13, with the most robust interhemispheric difference seen in the central spindles. The best individual-level prediction of unilateral CP was seen in the centro-occipital spindles with an overall accuracy of 93%. An empiric cut-off level for SPA at 0.65 gave a positive predictive value of 100% and a negative predictive value of 93% for later development of unilateral CP. INTERPRETATION: Our data suggest that automated analysis of interhemispheric SPA provides a potential biomarker of unilateral CP at a very early age. This holds promise for guiding the early diagnostic process in infants with a perinatally identified brain injury. WHAT THIS PAPER ADDS: Unilateral perinatal brain injury may affect the development of electroencephalogram (EEG) sleep spindles. Interhemispheric asymmetry in sleep spindles can be quantified with automated EEG analysis. Spindle power asymmetry can be a potential biomarker of unilateral cerebral palsy.

Botulinum toxin for the management of spasticity in multiple sclerosis: the Italian botulinum toxin network study.

BACKGROUND: Botulinum toxin (BT) is an effective and safe treatment for spasticity, with limited evidence in multiple sclerosis (MS). We aim to describe the use of BT for the management of MS spasticity in the clinical practice, its combination with other anti-spastic treatments in MS and possible MS clinical correlates. METHODS: This is a multicentre cross-sectional observational study including 386 MS patients, receiving BT for spasticity in 19 Italian centres (age 53.6 ± 10.9 years; female 228 (59.1%); disease duration 18.7 ± 9.2 years; baseline Expanded Disability Status Scale (EDSS) 6.5 (2.0-9.0)). RESULTS: BT was used for improving mobility (n = 170), functioning in activities of daily living (n = 56), pain (n = 56), posturing-hygiene (n = 63) and daily assistance (n = 41). BT formulations were AbobotulinumtoxinA (n = 138), OnabotulinumtoxinA (n = 133) and IncobotulinumtoxinA (n = 115). After conversion to unified dose units, higher BT dose was associated with higher EDSS (Coeff = 0.591; p < 0.001), higher modified Ashworth scale (Coeff = 0.796; p < 0.001) and non-ambulatory patients (Coeff = 209.382; p = 0.006). Lower BT dose was used in younger patients (Coeff = - 1.746; p = 0.009), with relapsing-remitting MS (Coeff = - 60.371; p = 0.012). BT dose was higher in patients with previous BT injections (Coeff = 5.167; p = 0.001), and with concomitant treatments (Coeff = 43.576; p = 0.022). Three patients (0.7%) reported on post-injection temporary asthenia/weakness (n = 2) and hypophonia (n = 1). CONCLUSION: BT was used for spasticity and its consequences from the early stages of MS, without significant adverse effects. MS-specific goals and injection characteristics can be used to refer MS patients to BT treatment, to decide for the strategy of BT injections and to guide the design of future clinical trials and observational studies.

Muscle-ultrasound evaluation in healthy pediatric subjects: Age-related normative data.

INTRODUCTION: The muscle ultrasound examination (MUS) is a noninvasive and inexpensive technique for evaluating neuromyopathies. Standardized MUS normative data are incomplete in pediatric subjects. METHODS: We performed a MUS study with 120 healthy children (59 males; mean age, 10.44 years; age range, 2-16 years). We measured the width and the echogenicity bilaterally in the following muscles: biceps brachii and brachialis, brachioradialis, forearm-flexors, rectus femoris and vastus intermedius, tibialis anterior, extensor hallucis longus, lateral and medial gastrocnemius. RESULTS: The muscle thickness increased with age for all muscles. Confidence limits were set for each age group muscle width. Echogenicity increased with age only in some muscles. DISCUSSIONS: Our MUS study provides new data on physiological muscle structural changes in healthy children to address the limited available references in this age group. Muscle Nerve 58: 245-250, 2018.

Multimodal neurophysiological monitoring in healthy infants born at term: normative continuous somatosensory evoked potentials data.

AIM: To describe accurate, standardized 1h-multimodal neurophysiological monitoring (1h-MNM), while simultaneously recording VEEG, aEEG, and SEP-C bilaterally from median nerves, and to collect neonatal normative SEP-C data related to behavioural states. METHOD: Twenty healthy, term newborn infants (13 males, 7 females; gestational age 37-42wks; mean 39.6wks, standard deviation [SD] 1.3wks) underwent 1h-MNM within 2 days of life, with focus on recording of the SEP-C (band-pass setting 1-100 Hz, rate of stimulation 1.1 Hz, 50 alternate stimuli). RESULTS: 1h-MNM was easily obtained with identification of cervical (N13) and cortical (N1, P1) SEP-C responses in all infants. SEP-C minimal and maximum N1 latencies/N1-P1 amplitudes were identified, bilaterally, during periods of spontaneous sleep active-quiet-active (AS-QS-AS) and quiet-wakefulness. Minimal latencies and amplitudes occurred in 60% of active sleep/quiet-wakefulness, with the maximums in 70% of quiet sleep. The SEP-C mean values were latencies of N13=13.6ms (SD 1.4ms) and N1=33.6ms (SD 3.9ms) to 34.2ms (SD 4.8ms) in left and right hemisphere respectively; central-conduction-time (CCT) (N13-N1), 20.0ms (SD 4.3ms) to 20.6ms (SD 4.8ms); N1-P1 amplitude=4.6ms (SD 2.7ms) to 3.8µV (SD 2.2µV). INTERPRETATION: 1h-MNM can record simultaneously VEEG/aEEG/SEP-C in newborn infants, showing the modulation of SEP cortical responses in relation to behavioural states in all infants studied using an appropriate neonatal method. We emphasize the importance of obtaining neonatal SEP-C normative data to better identify pathological findings in neonatal brain injury.

The cognitive reserve theory in the setting of pediatric-onset multiple sclerosis.

BACKGROUND: The study of cognitive reserve (CR) in relationship with cognitive impairment (CI) in pediatric-onset multiple sclerosis (POMS) may provide cues to identifying subjects at higher risk of impairment and scope for therapeutic strategies. OBJECTIVES: To assess the potential impact of CR on cognition in a cohort of POMS patients. METHODS: In all, 48 POMS patients were followed up for 4.7 ± 0.4 years. CI was defined as the failure of ⩾3 tests on an extensive neuropsychological battery. Change of neuropsychological performance was assessed through the Reliable Change Index (RCI) method. At baseline, CR was estimated by measuring the intelligence quotient (IQ). The relationships were assessed through multivariable regression analyses. RESULTS: At baseline, CI was detected in 14/48 (29.2%) patients. Two out of 57 healthy control (HC; 3.5%) met the same criteria of CI (p < 0.001). A deteriorating cognitive performance using the RCI method was observed in 18/48 patients (37.6%). Among the 34 cases who were cognitively preserved at baseline, a higher reserve predicted stable/improving performance (odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.03-1.20; p = 0.006). CONCLUSION: Our results suggest that higher CR in POMS patients may protect from CI, particularly in subjects with initial cognitive preservation, providing relevant implications for counseling and rehabilitation strategies.

Evaluation of the Relationship between Pain Exposure and Somatosensory Evoked Potentials in Preterm Infants: A Prospective Cohort Study.

BACKGROUND AND AIM: First, to compare somatosensory evoked potentials (SEPs) in preterm newborns without major brain injury studied at term equivalent age (TEA) with a term historical control group. Second, to investigate the impact of pain exposure during the first 28 days after birth on SEPs. Third, to evaluate the association between SEPs and Bayley-III at 2 years corrected age (CA). METHODS: Infants born at <32 weeks' gestational age (GA) were studied with continuous-SEPs. First, SEP differences between preterm and term infants were analyzed. Second, regression analyses were conducted to explore the association between SEPs and painful procedures, and then between SEPs and neurodevelopment. RESULTS: 86 preterm infants were prospectively enrolled. Preterm infants exhibited prolonged N1 latencies, central conduction times (CCTs), lower N1-P1 amplitudes, and more recurrently abnormal SEPs compared to term infants. Higher pain exposure predicted longer N1 latency and slower CCT (all p < 0.005), adjusting for clinical risk factors. Younger GA and postmenstrual age (PMA) at SEP recording were associated with longer N1 latency and lower N1-P1 amplitude (all p < 0.005). A normal SEP at TEA positively predicted cognitive outcome at 2 years CA (p < 0.005). CONCLUSION: Pain exposure and prematurity were risk factors for altered SEP parameters at TEA. SEPs predicted cognitive outcome.

Morphine exposure and prematurity affect flash visual evoked potentials in preterm infants.

Objective: The present study aimed to explore first the impact of perinatal risk factors on flash-VEP waves and morphology in a group of preterm infants studied at term equivalent age (TEA). Second, to correlate VEP morphology with neurological outcome at 2 years corrected age (CA). Methods: Infants with a gestational age (GA) at birth <32 weeks, without major brain injury, were enrolled. Multivariate regression analyses were performed, and the models were run separately for each dependent variable N2, P2, N3 latencies and P2 amplitude. Logistic regression was applied to study N4 component (present/absent) and VEP morphology (regular/irregular). The predictors were GA, bronchopulmonary dysplasia (BPD), postmenstrual age at VEP registration, cumulative morphine and fentanyl dose, and painful procedures. Lastly, linear regression models were performed to assess the relation between the Bayley-III cognitive and motor scores at 2 years CA and VEP morphology, in relation to GA, BPD, painful procedures and cumulative morphine dose. Results: Eighty infants were enrolled. Morphine was the predictor of N2 (R2 = 0.09, p = 0.006), P2 (R2 = 0.11, p = 0.002), and N3 (R2 = 0.13, p = 0.003) latencies. Younger GA was associated with lower amplitude (R2 = 0.05, p = 0.029). None of the independent variables predicted the presence of N4 component, nor VEP morphology in the logistic analysis. VEP morphology was not associated with cognitive and motor scores at 2 years. Conclusions: Morphine treatment and prematurity were risk factors for altered VEPs parameters at TEA. In our cohort VEP morphology did not predict neurological outcome. Significance: Morphine administration should be evaluated according to potential risks and benefits, and dosage individually accustomed, according to pain and comfort scores, considering the possible risk for neurodevelopmental impairment.

Aggregate Channel Features for newborn face detection in Neonatal Intensive Care Units.

An efficient face detector could be very helpful to point out possible neurological dysfunctions such as seizure events in Neonatal Intensive Care Units. However, its development is still challenging because large public datasets of newborns' faces are missing. Over the years several studies introduced semi-automatic approaches. This study proposes a fully automated face detector for newborns in Neonatal Intensive Care Units, based on the Aggregate Channel Feature algorithm. The developed method is tested on a dataset of video recordings from 42 full-term newborns collected at the Neuro-physiopathology and Neonatology Clinical Units, AOU Careggi, Firenze, Italy. The proposed system showed promising results, giving (mean ± standard error): log-Average Miss Rate = 0.47 ± 0.05 and Average Precision Recall = 0.61 ± 0.05. Moreover, achieved results highlighted interesting differences between newborns without seizures, newborns with electro-clinical seizures, and newborns with electrographic-only seizures. For both metrics statistically significant differences were found between patients with electro-clinical seizures and the other two groups. Clinical Relevance- The proposed method, based on quantitative physio-pathological features of facial movements, is of clinical relevance as it could speed up pain or seizure assessment of newborns in Neonatal Intensive Care Units.

Unilateral Transient Enhanced SEP during Integrated Multiparameter Neurophysiological Monitoring in a Newborn with Symptomatic Seizure.

During Integrated Multiparametric Neurophysiological Monitoring (IMNA), a newborn with suspected hypoxia at birth and microhaemorrhagic and ischaemic lesions presented some clonic-tonic episodes with specific EEG patterns characterized by rolandic and temporal spikes and the appearance of a unilateral enhanced Somatosensory Evoked Potential (SEP) (10.45 µv). Since the literature does not seem to describe cases of giant SEP in newborns, in this case report, we will discuss the hypotheses underlying this potential. It could be assumed that the ischaemic and haemorrhagic lesions presented by the newborn may have developed as a result of neurotransmitter balance failure. This may be the origin of the EEG picture, which, consequently, could have triggered a potential with high amplitude.

Heart Rate Variability Analysis for Seizure Detection in Neonatal Intensive Care Units.

In Neonatal Intensive Care Units (NICUs), the early detection of neonatal seizures is of utmost importance for a timely clinical intervention. Over the years, several neonatal seizure detection systems were proposed to detect neonatal seizures automatically and speed up seizure diagnosis, most based on the EEG signal analysis. Recently, research has focused on other possible seizure markers, such as electrocardiography (ECG). This work proposes an ECG-based NSD system to investigate the usefulness of heart rate variability (HRV) analysis to detect neonatal seizures in the NICUs. HRV analysis is performed considering time-domain, frequency-domain, entropy and multiscale entropy features. The performance is evaluated on a dataset of ECG signals from 51 full-term babies, 29 seizure-free. The proposed system gives results comparable to those reported in the literature: Area Under the Receiver Operating Characteristic Curve = 62%, Sensitivity = 47%, Specificity = 67%. Moreover, the system's performance is evaluated in a real clinical environment, inevitably affected by several artefacts. To the best of our knowledge, our study proposes for the first time a multi-feature ECG-based NSD system that also offers a comparative analysis between babies suffering from seizures and seizure-free ones.

Comparison of Sympathetic Skin Response (SSR) between Electrical and Acoustic Stimuli in a Healthy Pediatric Population.

Data in the literature report that latency and morphology in the cutaneous sympathetic skin response (SSR) do not change according to the type of stimulus delivered, unlike the amplitude which shows greater values in relation to the intensity of the physical impact caused in patient. Since the acoustic stimulus represents a method better tolerated by the pediatric patient, the aim of this study is to evaluate the presence or absence of significant differences in SSR between electrical and acoustic stimuli. The SSR was performed for each child of 18 recruited in this study, deriving from the palm of the hand and the sole of the foot and initially delivering an electrical stimulus at the level of the median nerve at the wrist. Two acoustic stimuli were subsequently delivered with the aid of audiometric headphones. Our results show no significant differences for the amplitude values obtained (p values > 0.05). For the latency there was a statistically significant difference (p-value = 0.001) for the left hand, subsequently not confirmed by the comparison performed between the two sides (p-values = 0.28 and 0.56). If these preliminary data are confirmed by a larger sample, the acoustic stimulus could be introduced in a standardized protocol for performing SSR in pediatric patients.

Consensus protocol for EEG and amplitude-integrated EEG assessment and monitoring in neonates.

The aim of this work is to establish inclusive guidelines on electroencephalography (EEG) applicable to all neonatal intensive care units (NICUs). Guidelines on ideal EEG monitoring for neonates are available, but there are significant barriers to their implementation in many centres around the world. These include barriers due to limited resources regarding the availability of equipment and technical and interpretive round-the-clock personnel. On the other hand, despite its limitations, amplitude-integrated EEG (aEEG) (previously called Cerebral Function Monitor [CFM]) is a common alternative used in NICUs. The Italian Neonatal Seizure Collaborative Network (INNESCO), working with all national scientific societies interested in the field of neonatal clinical neurophysiology, performed a systematic literature review and promoted interdisciplinary discussions among experts (neonatologists, paediatric neurologists, neurophysiologists, technicians) between 2017 and 2020 with the aim of elaborating shared recommendations. A consensus statement on videoEEG (vEEG) and aEEG for the principal neonatal indications was established. The authors propose a flexible frame of recommendations based on the complementary use of vEEG and aEEG applicable to the various neonatal units with different levels of complexity according to local resources and specific patient features. Suggestions for promoting cooperation between neonatologists, paediatric neurologists, and neurophysiologists, organisational restructuring, and teleneurophysiology implementation are provided.

Neuropsychological features in childhood and juvenile multiple sclerosis: five-year follow-up.

OBJECTIVE: The aim of the study was to perform a third cognitive assessment in our pediatric-onset multiple sclerosis (MS) patient cohort and determine predictors of the individual cognitive outcome. METHODS: After 4.7 ± 0.7 years from baseline evaluation, 48 of 63 patients in the original cohort were reassessed on an extensive neuropsychological battery and compared with 46 healthy controls. Two alternate versions of the tests were used at different assessment points. Cognitive impairment was defined as the failure of ≥3 tests; individual change in the cognitive impairment index was measured. RESULTS: At year 5, 38% of the subjects with MS fulfilled our criterion for impairment. Between years 2 and 5, regarding individual cognitive impairment index change, 66.7% of the patients improved. However, comparing baseline and 5-year testing (when the same versions of the tests were used), cognitive impairment index deterioration was observed in 56% of the patients, improvement in 25%, and stability in 18.8%. A deteriorating performance was related to male sex, younger age and age at MS onset, and lower education. None of these variables, however, was retained in the multivariate analysis. CONCLUSIONS: Cognitive outcome in pediatric-onset MS can be heterogeneous. Progression of cognitive problems in a few subjects and potential for compensation and improvement in others call for systematic cognitive screening in this population and development of effective treatment strategies.

Short term outcome of term newborns with unexpected umbilical cord arterial pH between 7.000 and 7.100.

BACKGROUND: The relationship between cord arterial pH (CA-pH) > 7.000 and the neonatal outcome is not clear. AIMS: To evaluate if asymptomatic infants born with unexpected cord arterial pH (CA-pH) between 7.000 and 7.100 develop clinical, biochemical, and instrumental signs of hypoxic cerebral, renal, and heart failure more frequently than symptomatic infants. STUDY DESIGN: Term infants with CA-pH of 7.000-7.100 and appropriate birth weight were prospectively and consecutively enrolled and classified as asymptomatic, when they had no resuscitation, early respiratory distress or early abnormal neurologic signs, and symptomatic infants. Clinical, biochemical, and instrumental signs of hypoxic cerebral, renal, and heart failure were evaluated in the two groups. RESULTS: A total of 53 infants were enrolled. Twenty-eight (53%) were asymptomatic. CA-pH was similar in both the groups, while the cTnI serum concentration in the first day of life and the occurrence of poor feeding were higher in the symptomatic than in asymptomatic infants. An arterial lactate level of ≥ 4.1 mmol/l measured in the first hour of life was an independent risk factor for the development of a symptomatic course. CONCLUSIONS: In our population the majority of infants born with a CA-pH between 7.000 and 7.100 were asymptomatic and would not have needed immediate admission to the neonatal care unit. Symptomatic infants showed a higher occurrence of subclinical heart injury and poor feeding.

The prognostic role of evoked potentials in neonatal hypoxic-ischemic insult.

Neonatal encephalopathy is a significant cause of infant mortality and morbidity with risk of neurological sequelae in the survivors of neonates admitted to Neonatal (N) Intensive Care Unit (ICU). The EEG and Evoked Potentials (EPs) are very informative in the ICU. In particular, it is known that the SomatoSensory (SS) EPs are the best single indicator of early prognosis in adults and children patients with traumatic and/or hypoxic-ischemic coma compared to the Glasgow Coma Scale (GCS) and CTscan. Most paediatric studies excluded newborns in an attempt to eliminate the age effects, because of the structural and functional immaturity of somatosensory system. In fact, newborns differ from adults and paediatric patients for many aspects: hypoxic-ischemic aetiology, SSEPs normative data, grading and predictive values, timing and techniques recording, clinical scales of evaluation. Recently a diagnostic and predictive role of early SSEPs has been established in perinatal hypoxic-ischemic. We reported a literature review of early diagnostic/prognostic role of SSEPs and our preliminary neurophysiological data of prospective study in mild or severe perinatal hypoxic-ischemic insult.

IgG and IgM antibodies to the refolded MOG(1-125) extracellular domain in humans.

Antibodies to MOG in serum have a dubious prognostic value in multiple sclerosis. The MOG recombinant protein conformational properties relevant to the antigenic activity are unknown. We employed a solid-phase ELISA based on a product (rMOG(ED)(His)(6)) expressed in E. coli after subcloning the cDNA of the extracellular domain of rat MOG, performing a refolding procedure on column and affinity purification. The far-UV Circular Dichroism (CD) spectra of rMOG(ED)(His)(6) showed a ß-sheet, a characteristic feature of the Ig-fold. However, in MS sera and controls we failed to detected IgM or IgG antibodies.

Prognostic value of somatosensory evoked potentials in comatose children: a systematic literature review.

PURPOSE: To review the predictive powers of SEPs in comatose children after acute brain injury. METHODS: MEDLINE, EMBASE, OVID, ISI Web of Knowledge, BIOMED Central and the Cochrane Library (1981-2007) were searched. First, predictive values were calculated for each primary study. Second, we analysed effects of different factors on the SEP diagnostic odds ratio by meta-regression. Third, we compared SEP predictive values in children and in adults. RESULTS: We selected 14 studies covering 732 patients; analysis was conducted in 11, while the other 3 were used for simple qualitative examination. In individual papers, the presence of SEP predicted favourable outcomes as shown by the area under both sROC curves being 0.958. The same value was shown by SEP absence for predicting unfavourable outcomes. All covariates showed no significant effects on diagnostic accuracy, but only a slight non-significant trend. For SEP grading, a simple sub-group analysis showed a high predictive value for non-awakening for absence of SEPs (PPV 97.0%) and a high prognostic power to predict awakening for normal SEPs (PPV 92.2%). Pathological SEPs did not show reliable predictivity. In children, the presence of SEPs showed a high prognostic power similar to that in adults. CONCLUSION: This study supports the use of SEPs in the integrated process of outcome prediction after acute brain injury in children. Caution is recommended in predicting unfavourable outcomes in patients with an absence of SEPs in both TBI and HIE comas. Future studies are needed to resolve the issue of the effect of aetiology and age on SEP's predictive power.

A Multicentre Database for Normative Brainstem Auditory Evoked Potentials (BAEPs) in Children: Methodology for Data Collection and Evaluation.

BACKGROUND: The influence of physiological and methodological factors on recordings of brainstem auditory evoked potentials (BAEPs) is greater in children than in adults. OBJECTIVE: To collect and evaluate BAEP data in normal children, and measure intra- and inter-laboratory variability. METHODS: Seven hundred and fifty unselected BAEP recordings were collected and evaluated from children ranging from neonates to 14-year-olds by eight laboratories in Italy. RESULTS: In newborns, three laboratories showed satisfactory concordance; wave I was more broadly distributed than wave V and IPL I-V. The evaluation of pooled BAEP data from the older children showed that laboratories with age-matched data gave overlapping results; those with unmatched-age data differed significantly. The sound intensities of the laboratories did not significantly affect absolute BAEP latencies or IPLs. Females had shorter latencies than males; the difference was not significant. A single exponential regression model was an adequate but not the best predictor of normal data. CONCLUSIONS: The pooled data were consistent with the physiological maturation of the brainstem acoustic pathway. The BAEPs was reliably normalised using the natural logarithm of age. The differences between Centres were related to sample size, measurement accuracy, and inclusion and selection criteria. SIGNIFICANCE: The creation of multicentre common database from an unmatched data collection is feasible and reliable enough for clinical diagnosis and multicentre clinical research.