Latah: an Indonesian startle syndrome.

The nature of culture-specific startles syndromes such as "Latah" in Indonesia and Malaysia is ill understood. Hypotheses concerning their origin include sociocultural behavior, psychiatric disorders, and neurological syndromes. The various disorders show striking similarities despite occurring in diverse cultural settings and genetically distant populations. They are characterized clinically by exaggerated startle responses and involuntary vocalizations, echolalia, and echopraxia. Quantifying startle reflexes may help define Latah within the 3 groups of startle syndromes: (1) hyperekplexia, (2) startle-induced disorders, and (3) neuropsychiatric startle syndromes. Twelve female Latah patients (mean age, 44.6 years; SD, 7.7 years) and 12 age-, sex- and socioeconomically matched controls (mean age, 42.3 year; SD, 8.0) were studied using structured history taking and neurological examination including provocation of vocalizations, echolalia, and echopraxia. We quantified auditory startle reflexes with electromyographic activity of 6 left-sided muscles following 104-dB tones. We defined 2 phases for the startle response: a short latency motor startle reflex initiated in the lower brain stem <100/120 ms) and a later, second phase more influenced by psychological factors (the "orienting reflex," 100/120-1000 ms after the stimulus). Early as well as late motor startle responses were significantly increased in patients compared with controls (P ≤ .05). Following their startle response, Latah patients showed stereotyped responses including vocalizations and echo phenomena. Startle responses were increased, but clinically these proved insignificant compared with the stereotyped behavioral responses following the startle response. This study supports the classification of Latah as a "neuropsychiatric startle syndrome."