Introduction

Paroxysmal eye movements are most frequently observed in epileptic seizures. A tonic ocular deviation may be the first sign of an epileptic seizure, but usually the eye movements are associated or followed by other extraocular movements and alteration of consciousness. However, non-epileptic paroxysmal eye movements can be observed in several other neurological disorders of childhood (Table 20.1) and this chapter will deal with some of them.

Ocular tics

Tics are the abnormal movement most frequently observed in children. Their frequency and their association with fascinating disturbances of human behaviour such as compulsion and obsessions, grants them a prominent place amongst paroxysmal movement disorders in children.

Tics are repetitive movements of skeletal (motor tics) or respiratory/nasopharyngo-laryngeal muscles (phonatory tics). They are considered as stereotyped, involuntary, sudden, inopportune, non-propositional, absurd, irresistible movements, of variable intensity.

The term tic designates both a symptom and a disease. As a symptom it has a wide variety of clinical manifestations. Tic diseases are even more polymorphous. They may be limited to simple, transient tics present for less than a year, or as in Tourette disease, patients may present with several types of chronic motor and phonatory tics, which are often associated with compulsive–obsessive disorder, attention deficit, non-appropriate behaviour or sleep disturbances.

Although tics per se are generally easy to identify even for the lay person, they may sometimes be difficult to distinguish from other abnormal movements. Simple tics should be differentiated from myoclonus and complex tics from choreic movements, dystonia and stereotypies. The capability of patients to temporally control their tics is a useful diagnostic feature.