[Abnormal electroencephalography results and specific language impairment: towards a theoretical neurodevelopmental model?]

Resting-state EEG alpha rhythm spectral power in children with specific language impairment: a cross-sectional study

PURPOSE

This study investigated EEG alpha rhythm spectral power in children with Specific Language Impairment (SLI) and compared it to typically developing children to better understand the electrophysiological characteristics of this disorder. Specifically, we explored resting-state EEG, because there are studies that point to it being linked to speech and language development.

METHODS

EEG recordings of 30 children diagnosed with specific language impairment and 30 typically developing children, aged 4.0-6.11 years, were carried out under eyes closed and eyes open conditions. Differences in alpha rhythm spectral power in relation to brain topography and experimental conditions were calculated.

RESULTS

In the eyes closed condition, alpha rhythm spectral power was statistically significantly lower in children with specific language impairment in the left temporal (T5) and occipital electrodes (O1, O2) than in typically developing children. In the eyes open condition, children with SLI showed significantly lower alpha rhythm spectral power in the left temporal (T3, T5), parietal (P3, Pz), and occipital electrodes (O1, O2). There were no statistically significant differences between the groups in relation to the relative change (the difference between average alpha rhythm spectral power during eyes closed condition and average alpha rhythm spectral power during eyes open condition divided by average alpha rhythm spectral power during eyes closed condition) in the alpha rhythm spectral power between the conditions.

CONCLUSION

Lower alpha rhythm spectral power in the left temporal, left, midline parietal, and occipital brain regions could be a valuable electrophysiological marker in children with SLI. Further investigation is needed to examine the connection between EEG alpha spectral power and general processing and memory deficits in patients with SLI.

Evaluation of patients with epileptiform activities in the posterior temporal-parietal-occipital regions

OBJECTIVE

The aim of this study was to determine the type, etiology and the rates of epilepsy and to identify accompanying cognitive and behavioral problems in patients with epileptiform abnormalities in the posterior cerebral localization.

METHODS

In this study, 3500 patients with at least one EEG record at the EEG Laboratory of Clinical Child Neurology Department of Cerrahpaşa Medical Faculty of Istanbul University were evaluated in 2014-2015. Three hundred forty-six patients were included in the study.

RESULTS

Of the 346 patients included in the study, 42.4% were female and 57.5% were male. The age range of the cases was 1-21 (mean: 8.7) years. Epileptiform activities were observed in post TPO region isolatedly in 58,95% (n = 204), post-TPO epileptiform focus with focal epileptiform focus in different localizations in 31.21% (n = 108), generalized epileptiform activity with more than one epileptiform focus in 9.8% (n= 34). In the period of EEG examinations 250 (72.25%) patients had a history of epileptic seizures and / or epilepsy, while 96 (27.74%) had non-epileptic clinical conditions such as behavioral disorder and autism.

CONCLUSION

In the EEG recordings we examined, sharp and spike wave activities were frequently observed in the post TPO region isolatedly. We believe that this study, which investigated the relationship between focal epilptiform activity in post TPO region and different clinical conditions, will serve as an example for other studies.

Developmental Language Disorder: Wake and Sleep Epileptiform Discharges and Co-morbid Neurodevelopmental Disorders

Developmental language disorder (DLD) is frequently associated with other developmental diseases and may lead to a handicap through adolescence or adulthood. The aim of our retrospective study was to characterize DLD subgroups, their etiological factors and clinical comorbidities, and the role of epileptiform discharges in wake and sleep recordings. Fifty-five children (42 male, mean age 6.2 ± 1.4 years, range 4-9 years) were included in the present study and underwent phoniatric, psychologic, neurologic, as well as wake and nocturnal electroencephalography (EEG) or polysomnography (PSG) examinations. A receptive form of DLD was determined in 34 children (63.0%), and an expressive form was found in 20 children (37.0%). Poor cooperation in one child did not permit exact classification. DLD children with the receptive form had significantly lower mean phonemic hearing (79.1% ± 10.9) in comparison with those with the expressive form (89.7% ± 6.2, p < 0.001). A high amount of perinatal risk factors was found in both groups (50.9%) as well as comorbid developmental diseases. Developmental motor coordination disorder was diagnosed in 33 children (61.1%), and attention deficit or hyperactivity disorder was diagnosed in 39 children (70.9%). Almost one half of DLD children (49.1%) showed abnormalities on the wake EEG; epileptiform discharges were found in 20 children (36.4%). Nocturnal EEG and PSG recordings showed enhanced epileptiform discharges, and they were found in 30 children (55.6%, p = 0.01). The wake EEG showed focal discharges predominantly in the temporal or temporo-parieto-occipital regions bilaterally, while in the sleep recordings, focal activity was shifted to the fronto-temporo-central areas (p < 0.001). Almost all epileptiform discharges appeared in non-rapid eye movement (NREM) sleep. A close connection was found between DLD and perinatal risk factors, as well as neurodevelopmental disorders. Epileptiform discharges showed an enhancement in nocturnal sleep, and the distribution of focal discharges changed.

The Value of Electroencephalogram in Assessing Children With Speech and Language Impairments

Purpose We sought to estimate the prevalence of isolated epileptiform activity (IEA) in children with speech and language impairments and discuss the utility of an electroencephalogram (EEG) in assessing these children. Method We conducted a systematic review and searched for eligible studies in 8 databases. All languages were included, and meta-analyses were performed. Results We found 55 prevalence estimates (8 with control group). The odds of having IEA were 6 times greater for children with speech and language impairments than for typically developing children. The overall pooled prevalence of IEA was 27.3%. A wide variation between the prevalence estimates was, to a certain degree, explained by type of impairment (8.1% in speech impairments, 25.8% in language impairments, and 51.5% in language regression). Sleep EEGs detected a significantly higher prevalence than awake EEGs. Although the presence of epilepsy gave a significantly higher prevalence than if epilepsy was not present, 33.5% of children with language impairment but without epilepsy were found to have IEA in sleep EEGs. Conclusions This systematic review shows that IEA is 6 times more prevalent in children with speech and language impairment than in typically developing children. However, the prevalence rates vary to a great extent. Uncovering IEA will, in addition to information from other clinical assessments, provide a more comprehensive understanding of the child's impairments. We argue that, although EEG is of questionable value when assessing children with speech impairments, sleep EEG could be valuable when assessing children with language impairments and, in particular, children who experience language regression.

EEG Abnormalities in Children with Speech and Language Impairment

INTRODUCTION

Epilepsy, a chronic condition of recurrent seizures, affects language, but the extent and nature of the language disturbance varies widely according to the type, severity, and cause of the epilepsy. There is paucity of literature on the electroencephalographic abnormalities in children with speech and language impairment. The present study was therefore planned to find the association of epileptiform EEG abnormalities in children with speech and language impairment and if present, their localization and lateralization to the language areas of the brain that are present predominantly in the left hemisphere.

MATERIALS AND METHODS

The study was conducted on Paediatric patients having speech and language impairment (n=94, age-2 to 8 years) selected on the basis of detailed history and neurologic examination. Video Electroencephalography (EEG) was performed as per American Clinical Neurophysiology Society guidelines using 16 channel RMS computerized EEG machine for a minimum of 40 minutes to capture both wakefulness and sleep along with activation procedures like hyperventilation (if feasible) and photic stimulation. EEG was reviewed for any abnormal EEG background, benign variants, interictal epileptiform discharges and ictal discharges.

RESULTS

In our cohort, 19.7% boys and 22.2% girls presented with seizures in their infancy and this gender difference was found to be statistically significant (p<0.05). EEG was abnormal in 47.9% children (45 out of 94) with no significant gender difference. Epileptiform EEG was seen in 73.6% of children with history of seizures and 41.3% of children without history of seizures (p<0.05). The EEG abnormities included: abnormal background (64.5%), presence of generalized interictal epileptiform discharges (57.8%), focal epileptiform discharges (20%) exclusively from left hemisphere and multifocal interictal epileptiform discharges (33.3%), each occurring in isolation or associated with other abnormities.

CONCLUSION

In the current study, it is definite that presence of generalized abnormalities in EEG are seen in higher frequency and focal interictal epileptiform discharges are solely seen in left hemisphere in children with speech and language impairment. Although, there is no distinct pattern of EEG abnormalities in such patients, we recommend a routine EEG in them and also brain imaging to complement the EEG findings.

Cognitive and electrophysiological characteristics of children with specific language impairment and subclinical epileptiform electroencephalogram

The current study is a preliminary examination of cognitive profiles and cortical distribution of the spectral power of different electroencephalogram (EEG) rhythms in children with specific language impairment and subclinical epileptiform discharges. Although a number of empirical studies point to higher incidence of abnormal EEGs in children with specific language impairment, only a few studies were found examining electrophysiological characteristics, such as locus of discharges and connections with cognitive functioning in this population of children. The sample included 12 children with specific language impairment (SLI) and abnormal EEG who underwent testing of cognitive functioning using the Wechsler Intelligence Scale for Children (WISC). The control sample included 13 children with specific language impairment and regular EEG. Results point to lower scores on several subtests of the performance scale for children with abnormal EEG than for the group with regular EEG. Detailed EEG analysis of cortical distribution of the spectral power of different EEG rhythms partially confirms the results of neuropsychological assessment, pointing to abnormal function of frontal and temporal regions. Higher values of spectral power of the delta brain rhythm in frontal regions are associated with lower results on the WISC performance scale. Results are discussed in the context of subgroups of the population of children with SLI.