Reconsidering the Clinical Outcome, Effect of Sex, and Diagnostic Criterion of Primary Complex Motor Stereotypies in Children.

BACKGROUND

Complex motor stereotypies (CMS) are repetitive movements classified into "primary" for typically developing individuals and "secondary" for those with other neurological or neurodevelopmental disorders. This study evaluated children diagnosed with primary CMS to assess motor stereotypy outcomes, sex-related differences, and early neurodevelopmental histories that play a key role in diagnostic classification.

METHODS

Sixty-five healthy participants diagnosed with pCMS (44 males, 21 females), mean age 9.1 ± 3.6 years (range 3-17 years), completed follow-up telephone interviews and questionnaires on symptom onset, medical history, and autism screens. Stereotypy severity was rated by both parents and affected children using the Stereotypy Severity Scale and Stereotypy Linear Analog Scale (SLAS).

RESULTS

The mean stereotypy onset was 1.2 ± 1.1 years. Stereotypy Severity Scale Motor and Global Impairment scores were positively correlated and showed that the Impairment score was significantly influenced by the Motor Interference score. Stereotypy severity was reduced in older individuals, primarily due to decreased Motor Intensity scores. Females showed greater Global Impairment after adjusting for age. Comorbidities included anxiety disorders (35%), attention-deficit/hyperactivity disorder (35%), tics/Tourette syndrome (9%), and obsessive-compulsive disorder (6%). A history of motor and/or speech delays was reported in 58%.

CONCLUSIONS

Although stereotypical symptoms were present in all subjects, there was an apparent age-related reduction in movement intensity. Stereotypies in females were associated with greater impairment in self-esteem, family life, school, and social acceptance. The presence of mild, early neurodevelopmental delays, and/or later appearing neuropsychiatric comorbidities is common among children with pCMS and should not be considered exclusionary for the diagnosis.