Short report Figure 1 Bilateral thalamic lesions associated with hemispatial neglect and impaired sustained attention, and amelioration with guanfacine. (A) Bilateral thalamic lesions as demonstrated by T2-weighted MRI scanning. The red arrow indicates one of the left-sided lesions, involving the medial thalamic nuclei, including the medio-dorsal nucleus. There are also smaller adjacent lesions in the pulvinar (blue arrow). The yellow arrow indicates the right-sided lesion, which is also in the pulvinar. (B) Line bisection. The rightward deviation on bisecting 17 cm lines decreased signiﬁcantly after commencement of guanfacine (deviation given in mm). (C) Line cancellation. The total number of lines cancelled by the patient increased on 2 mg of guanfacine. (D) Perceptual sensitivity on the sustained attention task improved signiﬁcantly on guanfacine treatment. Pre, preguanfacine; Post 1, initial assessment after commencement of 2 mg of guanfacine; Off, assessment at 2 months after guanfacine had been ceased for 2 weeks; Post 2, assessments at 6 months after initiation of guanfacine; Post 3, assessment at 16 months after initiation of guanfacine. tests were used to assess neglect, while a computerised task was used to measure the deﬁcit in sustained attention. The neglect tests used were line cancellation, in which subjects are instructed to cancel all the lines they can ﬁnd (total 40) distributed across an A4 sheet of paper and bisection of 17 cm horizontal lines, where the mean deviation rightwards from centre was taken from three attempts. The computerised task which has been used previously7 was presented on a Dell Lati- tude D820 laptop computer, and entailed the subject depressing the central button on a response box (RB-530 Cedrus Corp.), whenever an infrequently occurring black circle (8 mm diam- eter) occurred. The circle remained on the screen for 1 s and was presented on a grey background with interstimulus intervals of 1e7 s. 100 stimuli were presented over a total period of 8 min. Responses quicker than 100 ms were classiﬁed as anticipa- tions, and therefore as commission errors, as were responses occurring more than 1600 ms after target onset. Perceptual sensitivity, or d9, which is derived from signal detection theory8 and takes into account commission as well as omission errors, was the behavioural outcome measure of this task and calcu- lated according to the formula below: d 9 ¼ F 1ðHÞ F 1 F ð Þ where H is the hit rate, and F is the false alarm rate. The higher this value, the better the subject was at accurately detecting targets. These tests were performed on two consecutive days prior to commencing guanfacine, as well as at several time points after its introduction. The dose of guanfacine was titrated up slowly over 3 days in the following increments: 0.5 mg, 1 mg and 2 mg as single daily doses. The ﬁrst on-guanfacine testing session was performed the day 2 mg was reached. J Neurol Neurosurg Psychiatry 2011;82:688e690. doi:10.1136/jnnp.2009.195792 An additional testing session off-guanfacine was performed 2 months later (due to initial difﬁculty obtaining the drug locally) at which point the patient had not received guanfacine for 2 weeks. Three on-guanfacine testing sessions were performed 6 months after the initial commencement of 2 mg of guanfacine daily, and a ﬁnal session occurred a further 10 months later. Therefore, in total, the patient underwent three testing sessions off and ﬁve on guanfacine. Testing was always performed during the afternoon. Guanfacine has previously been well tolerated in studies investigating its efﬁcacy in children and adolescents with attention deﬁcit/hyperactivity disorder; however, the most commonly experienced side effects include drowsiness, sedation and dizziness.5 9 The patient reported here did not experience any side effects. RESULTS Figure 1A demonstrates the thalamic lesions on T2-weighted MRI, along with performance on attention tests on and off guanfacine. The thalamic lesions localise to the medial thalamic nuclei (including the mediodorsal nucleus) and pulvinar on the left and to the pulvinar on the right.10 Lesions of the right pulvinar have previously been linked to the pathogenesis of neglect,11 while the patient’s remaining small lesions (in the cerebellum, temporal and occipital lobes) all lie outside areas commonly associated with the syndrome, such as the inferior parietal lobe, temporoparietal junction and inferior frontal lobe.12 13 All three measures used to assess attention deﬁcits improved on guanfacine. Permutation testing was used to investigate whether these effects were statistically signiﬁcant. This estab- lished procedure has speciﬁcally been used in single-case designs 689