威廉斯综合征儿童的视觉注意功能

Visual search attention in children with Williams syndrome

目的探讨威廉斯综合征（WS）儿童的视觉注意功能。方法2004年7月至2007年1月共135例儿童参加了测试。WS组22例，平均12（6～16）岁，其中男13例，女9例；唐氏综合征（DS）组25例，平均年龄12（7—16）岁，男21例，女4例；同年龄对照组45名，平均年龄12（6—16）岁，男27名，女18名；同智龄对照组43名，平均年龄4（2～8）岁，男23名，女20名。采用皮勃迪图片词汇测试（PPVT）进行智龄匹配。使用一套视觉搜索任务测试4组儿童的选择性注意、转移性注意和持续性注意功能并进行比较。结果（1）单目标搜索任务中，没有与目标相似的干扰因素存在时，WS组儿童的正确反应率比同年龄对照组儿童低（71％±25％VS87％±14％，P=0．001），平均反应时间长（5s vs 3s，P=0．000），平均反应距离长（相对单位：25VS18，P=0．000），与DS组儿童比较，WS组儿童平均反应时间较长（5s vs 3s，P=0．022），但是与同智龄对照组儿童的表现相当；错误类型分析发现仅形状错误发生率比同年龄对照组儿童高（15％ vs 0，P=0．000）。在增加与目标刺激颜色相同、形状相近的干扰刺激后，WS组儿童的表现比同年龄对照组及同智龄对照组都差，表现为正确反应率低（39％±20％ vs 77％±23％VS66％±23％，均P=0．000），平均反应时间长（13s vs 3s vs 5s，均P=0．000），搜索距离长（41VS20VS27，P=0．000、P=0．004），形状错误发生率比同年龄对照组及同智龄对照组都高（14％vs 0 vs 7％，P=0．000、P=0．017），但是与DS组儿童差异无统计学意义。（2）双目标交替搜索的转移性任务显示WS组儿童的转移性注意正确反应率较同年龄对照组低，平均反应时间长，搜索距离长（52％±28％、11s、54±27VS78％±22％、4s、31±13，均P=0．000），各指标与DS组儿童及同智龄对照组儿童差异均无统计学意义。WS组转移错误发生率比同年龄对照组和同智龄对照组儿童高（13％、0、4％，P=0．000、P=0．004）。（3）警觉任务发现WS组儿童持续性注意的正确反应率较同年龄对照组儿童低（52％±25％ vs 80％±21％，P=0．000），平均反应时间长（4s±1s vs 3s±1s，P=0．000），错误点击数高（8vs3，P=0．000），但和DS组比较差异无统计学意义。结论WS组儿童存在视觉注意功能缺陷。

Objective To explore the characteristics of visual search attention in children with Williams syndrome （WS）. Methods Twenty-two children with WS, 13 male and 9 female, aged 12 （6 - 16）, 25 chronological age （CA） and mental age （MA）-matched children with Down＇s syndrome （DS）, 45 biological age-matched children, and 43 mental age-matched children, aged 4 ± 2 （ 2 - 8 ） underwent Peabody picture vocabulary test （PPVT）. Visual search attention including selective, switch, and sustained attention, was tested using a set of computerized visual search tasks via a touch-screen. In the dual target tasks, participants were required to alternate between two different targets. Sustained attention was investigated with vigilance task test. Results （ 1 ） In the single-target searching task with no target similar distracter, the accurate response rate of the WS patients was 71% ± 25%, significantly lower than that of the CA-matched children （87% ± 14%, P = 0. 001）. The searching time of the WS children was 5 s, significantly longer than that of the CA-matched children （3 s, P = 0. 000）. The distance for touch of the WS children was 25 relative units, significantly longer than that of the CA-matched children （18 relative units, P = 0. 000）. The mean reaction time of the WS children was 5 s, significantly longer than that of the children with Down＇s syndrome （3 s, P =0. 022）. The shape error rate of the WS children was 15%, significantly higher than that of the CA-matched children （0, P =0. 000）. When non-targets similar to the targets were added, the accurate response rate of the WS group was 39% ± 20%, significantly lower than those of the CA-matched and MA-matched children （77% ± 23% and 66% ± 23% respectively, both P = 0. 000） ; the mean searching time of the WS children was 13 s, significantly longer than those of the CA-matched and MA-matched children （3 s and 5 s respectively, both P = 0. 000） ; and the distance per touch of the WS children was 41 relative units, significantly longer than those of the CA-matched and MA- matched children （20 and 27 relative units, P = 0.000 and P = 0.004）. （2） The results of the dual target tasks showed that the accurate response rate of the WS children was 52% ± 28% , significantly lower than that of the CA-matched children （78% ±22%, P =0. 000）, the mean searching time of the WS children was 11 s, significantly longer than that of the CA-matched children （4 s, P =0. 000） ; and the distance per touch of the WS children was 54 ± 27 relative units, significantly longer than that of the CA-matched children （31 ± 13 relative units, P = 0. 000）. However, there were not significant differences in the accurate response rate, mean searching time, and distance per touch between the WS and DS children. The switching error rate of the WS children was 13%, significantly higher than those of the CA and MA-matched children （0 and 4% respectively, P = 0.000 and P = 0. 004 ）. （3） The vigilance task test showed that the accurate response rate of the WS children was 52% ± 25%, significantly lower than that of the CA-matched children （80% ± 21%, P = 0.000） ; the mean searching time of the WS children was 4 s ± 1 s, significantly longer than that of the CA-matched children （ 3 s ± 1 s, P = 0. 000） ; and the error hit number of the WS children was 8, significantly more than that of the CA-matched children （3, P = 0. 000）. However, there were not significant differences in the accurate response rate, mean searching time, and error hit number between the WS and DS children. Conchusion Distinct visual search deficits exist in WS children.