Ancient human parallel lineages within North America contributed to a coastal expansion.

Little is known regarding the first people to enter the Americas and their genetic legacy. Genomic analysis of the oldest human remains from the Americas showed a direct relationship between a Clovis-related ancestral population and all modern Central and South Americans as well as a deep split separating them from North Americans in Canada. We present 91 ancient human genomes from California and Southwestern Ontario and demonstrate the existence of two distinct ancestries in North America, which possibly split south of the ice sheets. A contribution from both of these ancestral populations is found in all modern Central and South Americans. The proportions of these two ancestries in ancient and modern populations are consistent with a coastal dispersal and multiple admixture events.

Hyperkinetic seizures in children.

The objective of this study was to delineate the clinical and video-electroencephalographic (EEG) manifestations of children with complex partial seizures with a predominant "hyperkinetic" presentation. Certain types of partial seizures can be difficult to differentiate from nonepileptic seizures because of their intense motor presentation and, at times, lack of alteration of consciousness. Based on a published semiologic seizure classification, this type of seizures can be described as "hyperkinetic," characterized by intense motor activity involving the extremities and trunk. We report five children diagnosed with hyperkinetic seizures by video-EEG monitoring. All patients were referred for video-EEG evaluation because of an initial suspicion of pseudoseizures. Presented in this study is a review of the patients' clinical data, including video-EEG evaluation. There were three boys and two girls; the mean age at presentation was 10 +/- 3 years. In four patients, there was a history of behavioral disorder, with two patients carrying a diagnosis of attention-deficit hyperactivity disorder (ADHD). One girl had significant developmental delay and an abnormal neurologic examination. Brain magnetic resonance imaging was normal in three patients and abnormal in two. The semiology of the seizures consisted of stereotypic intense motor activity, mainly upper extremity flailing and kicking. Screaming and shouting were noted in three cases, and intense fear was present in two patients. The hyperkinetic ictal activity progressed to tonic-clonic seizures in two patients. Seizures occurred out of sleep or on awakening in four patients. The interictal EEG activity was normal in one patient and revealed a continuous generalized slowing and slowing of the posterior dominant rhythm in two patients. One of the latter patients had interictal epileptiform activity in the frontal and midline regions. An intermittent rhythmic slow activity of the left hemisphere with superimposed bifrontal sharp waves was noted in the fifth patient. The ictal EEG revealed profuse superimposed electromyographic (EMG) activity in all patients, making some of the EEG interpretation difficult to analyze, particularly a longitudinal bipolar montage. However, with digital manipulation of the ictal EEG data, such as changes in EEG sensitivity, application of fast frequency filters, and use of different EEG montages, it was possible to discern an ictal EEG pattern or postictal slowing following the diffuse EMG artifact in all patients. On clinical follow-up, adequate seizure control was achieved in three patients. Based on the clinical history, one patient was diagnosed with autosomal dominant nocturnal frontal lobe epilepsy. Diagnosis of hyperkinetic seizures can be difficult because of the similarity of the clinical manifestations with nonepileptic events such as certain parasomnias and pseudoseizures. Video-EEG is the most effective way of diagnosing this type of seizure.