Deep Tendon Reflex

In a normal person, when a muscle tendon is tapped briskly, the muscle immediately contracts due to a two-neuron reflex arc involving the spinal or brainstem segment that innervates the muscle. The afferent neuron whose cell body lies in a dorsal root ganglion innervates the muscle or Golgi tendon organ associated with the muscles; the efferent neuron is an alpha motoneuron in the anterior horn of the cord. The cerebral cortex and a number of brainstem nuclei exert influence over the sensory input of the muscle spindles by means of the gamma motoneurons that are located in the anterior horn; these neurons supply a set of muscle fibers that control the length of the muscle spindle itself.

Hyporeflexia is an absent or diminished response to tapping. It usually indicates a disease that involves one or more of the components of the two-neuron reflex arc itself.

Hyperreflexia refers to hyperactive or repeating (clonic) reflexes. These usually indicate an interruption of corticospinal and other descending pathways that influence the reflex arc due to a suprasegmental lesion, that is, a lesion above the level of the spinal reflex pathways.

Benign Childhood Epilepsy

Epilepsy is defined as 2 or more unprovoked seizures. The various types of epilepsy differ in many aspects, including (1) age of onset, (2) semiology, (3) EEG findings, and (4) outcome. In 1987, Freeman et al reported that most children with generalized tonic-clonic seizures have a benign developmental disorder that reduces their seizure threshold and will be outgrown. This disorder has been termed benign childhood epilepsy and is thought to be secondary to CNS immaturity.

In this article the term benign epilepsy is used to refer to a group of pediatric epileptic disorders in which remission and lack of significant neurologic sequelae are expected in the vast majority of patients. These disorders are idiopathic, occur in otherwise healthy children, and have (with rare exceptions) a strong genetic component. They include both generalized epilepsies and partial epilepsies. These epilepsies are presented according to the age of onset, starting from the neonatal period.

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