The late features of kernicterus include all except

Hypotonia is not a feature of kernicterus . Initial findings associated with kernicterus may vary from case to case, but often include lack of energy (lethargy) or drowsiness, poor feeding habits, fever, a shrill high-pitched cry, and/or absence of ceain reflexes (e.g., Moro reflex, etc.). Affected infants may eventually experience respiratory distress, mild to severe muscle spasms including those in which the head and heels are bent backward and the body bows forward (opisthotonus), and/or diminished muscle tone (hypotonia). As an affected infants ages, other symptoms and physical findings may develop including delayed and/or abnormal motions or motor development; convulsions or seizures; impaired ability to coordinate voluntary movements (ataxia); abnormal muscle rigidity resulting in muscle spasms (dystonia); slow, continuous, involuntary, writhing movements (athetosis) of the arms and legs (limbs) and/or entire body; problems with sensory perception; lack of upward gaze; and/or hearing loss. In some cases, affected infants may exhibit mental retardation and difficulty speaking (dysahria). In most cases, the syndrome characteristic of kernicterus develops by three to four years of age. Reference: GHAI Essential pediatrics, 8th edition