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Objectives and Background: This experiment sought to quantify the extent to which patients with Huntington disease (HD) have difficulties in orienting attention, via a vibrotactile version of a Posner-type cost-benefit paradigm., Method: Participants were required to push a button in response to a vibration delivered to the index finger of either hand. Prior to each stimulus vibration, a precue (valid, neutral, or invalid) was delivered to the finger. Benefits and costs were calculated from valid and invalid precues., Results: Although patients with HD were overall slower than the controls, their performance was no different; both patients and controls demonstrated increased benefits from valid compared with invalid and neutral cues. Of interest was the finding that patients, unlike controls, performed significantly slower with the cue presented to the left compared with the right side. The crossed arm configuration proved to be too difficult for the patients with HD, and thus an analysis on these data was not permitted., Conclusions: Patients may experience difficulties in allocating attentional resources toward their left nonpreferred hand. Overall, findings demonstrate that patients with HD, with minimal caudate damage at early stages of disease onset, may not experience problems in their ability to orient attention.

Tourette's Syndrome (TS) is a basal ganglia (BG) disorder characterized by involuntary motor and vocal tics, impairment of voluntary motor function, and attentional dysfunctions. This experiment aimed to investigate motor reprogramming and inhibitory control in adult TS patients. Ten TS patients and 10 age- and sex-matched controls performed sequences of movements in response to the illumination of LED lights, and were required to interrupt a predictable, reciprocating sequence of leftward and rightward movements in order to move to an unpredictable target that occurred either in the direction opposite to that expected, or in the opposite direction and at twice the expected distance. Results showed that TS patients were no slower than controls in reprogramming the direction and distance of movements, thus showing no overall deficits in inhibitory control. Of interest, however, was a directional asymmetry (right bias) in movement preparation time in TS patients. Patients with TS may have a superiority in allocating attentional resources toward the right side, contralateral to the implicated reduced BG volume in this disorder. These findings extend earlier work reporting anomalous BG lateralization in TS.

Gilles de la Tourette syndrome is characterised by tics, although patients also commonly present with attentional problems. This experiment aimed to ascertain whether TS patients have problems in orienting attention, via the use of a vibrotactile choice reaction time task. Participants were required to push a button in response to a faint vibration delivered to the index finger. Prior to each stimulus vibration, a pre-cue (valid, neutral or invalid) was administered to the finger. The performance benefits and costs participants gained from valid and invalid precues were calculated. Contrary to our prediction TS patients did not show significantly different costs or benefits. Furthermore, both patients and controls showed an equal and increased benefit in the crossed arm posture, compared to the uncrossed. These results suggest TS patients do not generally have problems in orienting attention. In addition, in the tactile modality, both patients and controls may benefit from directed attention when difficulty levels are maximal.