A tic is a sudden, rapid, recurrent, nonrhythmic motor movement or vocalization. Motor and phonic tics in a course of over 1
year that first occured before 18 years are the main features of Gilles de la Tourette syndrome (GTS). Psychogenic/functional ( P/F)
tics were considered as a diagnosis made per exlusionem in lack of agreement of diagnostic criteria. Recently, emphasis is in r ather
highlighting positive signs when making diagnosis of P/F tics. Several features in clinical course are important to differentia te GTS
from P/F tics. Some of them are acute onset in adulthood, precipitation by physical event, absent family history of tics, varia ble,
complex and inconsistent phenomenology, suggestibiity, distractibility. Premonitory urge, feeling of excessive energy and being
\u27wound up\u27 prior tic, is a usual feature of GTS unlike in P/F tics. If present, such premonitory urge have different qualitativ e and
quantitative marks. Another possible diagnostics tool could be the beireitshaftspotential, an event-related electrical potentia l
associated to initiation of movement which is divided in two phases, early (B1) and late (B2) phase. Early phase, whose occuren ce in
some papers has been reported prior P/F tics, is absent prior performed tic in GTS. In everyday clinical practice differentiati ng GTS
from P/F tics is often very challenging but taking proper medical history, paying more attention to positive signs and possibly using
electroneurophysiology tests could contribute in making the right diagnosis