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### Clinical and neuropsychological studies  Many studies have examined the effects of In an intriguing report from a group studying social cognition in TS,  TS on neuropsychological variables. Some of these variables seem directly related to tic generation (i.e., difficulties with motor inhibition) but many studies have revealed wide-ranging effects. subjects and controls demonstrated intact mentalizing when observing animated triangles demonstrating simple and complex interactions \citep*{26177119}.  However,given the high rates of comorbidities, researchers are generally trying to perform studies with sufficient power to separate effects associated with  TS itself and those related subjects also tended  to TS-comorbidities. attribute human-like intentions when two triangles were moving randomly. This tendency was not explained by clinical symptoms or by other constructs such as executive function or alexithymia.  Social, cognitive, and sensorimotor abilities associated with TS have been studied by many researchers. In an intriguing report from a group studying social cognition in TS, TS subjects and controls demonstrated intact mentalizing when observing animated triangles demonstrating simple and complex interactions \citep*{26177119}. However, TS subjects also tended to attribute human-like intentions when two triangles were moving randomly. This tendency was not explained by clinical symptoms or by other constructs such as executive function or alexithymia. Two studies examined the effects of comorbidities on social and cognitive skills. Social responsiveness and cognitive flexibility were examined in TS children and adolescents \citep{25631951}. TS subjects were rated as having poorer social motivation and skills, using the Social Responsiveness Scale, compared to age-matched controls. TS subjects also took significantly longer to complete the Trail Making Tests which measure cognitive flexibility and visual motor integration. However, of the 31 TS subjects, 11 had OCD, 18 had ADHD and 8 had an anxiety disorder. Once these comorbidities were taken into account, group differences on the Trail Making Tests and the Social Responsiveness Scale were no longer significant. These findings demonstrate the need for studies to have adequate sample sizes to provide sufficient power to disentangle effectsdue to TS directly and those  related specifically to tics versus  to comorbid conditions. other symptoms.  Another study was designed to separate effects due attributable  to OCDand TS  \citep{25296570}. Sustained attention, using a continuous performance test, was examined in 48 children and adolescents who had OCD alone, tic disorders (TD) alone or both OCD and TD. A high rate of ADHD was seen in all groups (62% of the OCD+TD group, 27% in the TD alone group, and 20% in the OCD alone group). Anxiety was also frequent (77% in the OCD+TD group compared to 49% for the other two groups combined). The OCD+TD group had more errors of omission and higher reaction time variability. These results of this study provide additional evidence that the OCD+TD phenotype is associated with more severe symptoms including attentional difficulties and symptoms of anxiety.Sensory sensitivity was compared in adults with "pure" TS and controls by establishing thresholds for externally applied stimuli \cite{26818628}. No differences were found between the two groups supporting the view that the sensory abnormalities seen in TS may be related to abnormal interoceptive awareness or abnormal central sensorimotor processing.  Twoother  studies examined motor control. In a clever analysis of video recordings of the eyes \citep{26175694}, spontaneous blink rate, which is related to dopamine levels, was higher in children with TS than in controls both during task performance and during a rest period. In contrast, pupil diameter, which is related to norepinephrine levels, was correlated with anxiety in TS subjects although not in controls. Researchers also used a cognitive control task to measure ability to properly update current task information, ignore competing information when selecting between response options, and retrieve and use relevant response contingencies. Accuracy on this cognitive control task accounted for half of tic severity variance. In an unrelated study, TS children, without ADHD or OCD, had significantly greater difficulty maintaining postural stability than did age- and gender-matched controls, especially when subjects had access only to accurate vestibular, rather than visual or somatosensory, cues \citep{25683311}. Somatosensory sensitivity was compared in adults with "pure" TS and controls by establishing thresholds for externally applied stimuli \cite{26818628}. No differences were found between the two groups supporting the view that the sensory abnormalities seen in TS may be related to abnormal interoceptive awareness or abnormal central sensorimotor processing.  Three recent studies examined the effects of attention on tic frequency and the results have implications for how treatment protocols could be modified to increase effectiveness. The role of attention on tic frequency was examined under several conditions \citep{25185800}. Tic frequencies were lower for 12 TS subjects during a baseline condition when they were alone in a room compared to when they were alone in a room looking at themselves in a mirror. A second study was performed to determine whether the increase in frequency was due to increased attention to the tics themselves or due to increased self-awareness in general. In addition to the conditions previously described, 16 subjects were also shown videos of themselves while they were not ticcing. Tic frequency was again lower during the baseline compared to the mirror condition. Tic frequency was even lower when subjects were watching the video of themselves while not ticcing. The authors suggest that future treatments teach patients to attend to states when they experience fewer tics. Another study of TS adults \citep{25486384} compared tic frequency while subjects were engaged in tasks that involved attending to particular fingers, colored circles, or whether a tic had occurred during a specific 2-second interval. Observations for these tasks were made both during free ticcing and tic suppression. Not surprisingly, more tics were seen during a baseline free ticcing condition. During the attention tasks, tic frequency was greatest while subjects focused on their tics. In contrast, tic frequency decreased during the color attention condition and decreased further during the finger attention condition. When subjects suppressed their tics, they reduced their baseline tic frequency similarly across all attention conditions. The results are consistent with the idea that internally-directed attention, especially with a focus on tics, may contribute to momentary increases in tic severity. The authors suggested that behavioral treatment might be more effective if it focused on teaching patients to focus on external events and voluntary actions when they are in situations that are most likely to result in ticcing. Anecdotal evidence has suggested that tics decrease when people are involved in musical activity, so \citet{Bodeck_2015} systematically studied the effects of music. Questionnaires completed by 29 patients supported the idea that listening to music and performing music decrease tic frequency. TS subjects were then observed in a variety of conditions. Tics were almost completely eliminated when subjects were performing music. Listening to music and mental imagery of musical performance also resulted in decreases in tic frequency. The authors suggested that focused attention, along with fine motor control and goal-directed behavior, produced the decrease in tics.