Neglect 3 right of the true midposition (Schenkenberg. of arrays in which targets are difficult to discrimi- Bradford,Ajax,1980).Patients make larger nate from distracter stimuli (Rapcsak,Verfaellie. errors with longer lines (Chatterjee.Dajani.& Fleet,Heilman.1989)may increase the sensitiv- Gage 1994a)If stimuli are placed in space con ity of cancellation tasks.Thus,using arrays with a tralateral to their lesion.patients frequently make large number of stimuli (generally more than fifty) larger errors (Heilman Valenstein.1979).Thus and with distracters that are difficult to discrimina using long lines (generally greater than 20cm) from the targets increases the sensitivity of cancel placed to the left of the patic s trunk increases the onal neglect. sensitivity of detecting extrapersonal neglect using In drawing tasks.pa line bisection tasks Cancellation tasks assess how well a patient me ory (fi s 1.3 and 1.4).Wher explores the contralesional side of extrar asked to with multiple objects. e (figure 1.2).Patients are gets which they nted with a ts with cts in the parts, tasks are adm inis ithou left side of individual whe ns and the in the art at the 6 y,pate in a ve left sided 992a. may ven misplace neglect 1973)and ofte ody,s quadra at a target in th 1992 owe to be ading ta asks can be given by having patie nt Ricci 1999 nan, 1997. patient cancel negiect may sided targets repeatedly. Inc sing the number of D inging their gaze to the left margi ne page targets may uncover neglect that is not evident on ng t may arrays with fewer targets(Chatterjee,Mennemeier. lines starting in the middle of the page and prod Heilman.1992b:Chatterjee et al..1999).The use sequences of words or sentences that do not make sense.When reading single words,they may eithe omit left-sided letters or substitute confabulated letters (Chatterjee,1995).Thus the word "walnut might be read as either "nut"or "peanut."This reading disorder is called "neglect dyslexia" (Kinsboure Warrington.1962). Extinction to Double Simultaneous Stimulation Patients who are aware of single left-sided stimuli may neglect or "extinguish"these stimuli when left-sided stimuli are presented simultaneously with right-sided stimuli(Bender Furlow,1945) Figure 1.2 Extinction may occur for visual,auditory,or tactile ample of a cancellation task showing left neglect.Tha stimuli (Heilman.Pandya.Geschwind,1970). Visual extinction can be assessed by asking patients SK Is given wit ut me constraints and without restrict ng eye or hea moven to count fingers or to report finger movementsright of the true midposition (Schenkenberg, Bradford, & Ajax, 1980). Patients make larger errors with longer lines (Chatterjee, Dajani, & Gage, 1994a). If stimuli are placed in space con￾tralateral to their lesion, patients frequently make larger errors (Heilman & Valenstein, 1979). Thus, using long lines (generally greater than 20cm) placed to the left of the patient’s trunk increases the sensitivity of detecting extrapersonal neglect using line bisection tasks. Cancellation tasks assess how well a patient explores the contralesional side of extrapersonal space (figure 1.2). Patients are presented with arrays of targets which they are asked to “cancel.” Cancellation tasks are also administered without restricting head or eye movements and without time limitations. Patients typically start at the top right of the display and often search in a vertical pattern (Chatterjee, Mennemeier, & Heilman, 1992a). They neglect left-sided targets (Albert, 1973) and often targets close to their body, so that a target in the left lower quadrant is most likely to be ignored (Chatterjee, Thompson, & Ricci, 1999; Mark & Heilman, 1997). Sometimes patients cancel right￾sided targets repeatedly. Increasing the number of targets may uncover neglect that is not evident on arrays with fewer targets (Chatterjee, Mennemeier, & Heilman, 1992b; Chatterjee et al., 1999). The use of arrays in which targets are difficult to discrimi￾nate from distracter stimuli (Rapcsak, Verfaellie, Fleet, & Heilman, 1989) may increase the sensitiv￾ity of cancellation tasks. Thus, using arrays with a large number of stimuli (generally more than fifty) and with distracters that are difficult to discriminate from the targets increases the sensitivity of cancel￾lation tasks in detecting extrapersonal neglect. In drawing tasks, patients are asked to either copy drawings presented to them or to draw objects and scenes from memory (figures 1.3 and 1.4). When asked to copy drawings with multiple objects, or complex objects with multiple parts, patients may omit left-sided objects in the array and/or omit the left side of individual objects, regardless of where they appear in the array (Marshall & Halligan, 1993; Seki & Ishiai, 1996). Occasionally, patients may draw left-sided features of target items with less detail or even misplace left-sided details to the right side of their drawings (Halligan, Marshall, & Wade, 1992). Reading tasks can be given by having patients read text or by having them read single words. Patients with left-sided neglect may have trouble bringing their gaze to the left margin of the page when reading text. As a consequence, they may read lines starting in the middle of the page and produce sequences of words or sentences that do not make sense. When reading single words, they may either omit left-sided letters or substitute confabulated letters (Chatterjee, 1995). Thus the word “walnut” might be read as either “nut” or “peanut.” This reading disorder is called “neglect dyslexia” (Kinsbourne & Warrington, 1962). Extinction to Double Simultaneous Stimulation Patients who are aware of single left-sided stimuli may neglect or “extinguish” these stimuli when left-sided stimuli are presented simultaneously with right-sided stimuli (Bender & Furlow, 1945). Extinction may occur for visual, auditory, or tactile stimuli (Heilman, Pandya, & Geschwind, 1970). Visual extinction can be assessed by asking patients to count fingers or to report finger movements Neglect 3 Figure 1.2 Example of a cancellation task showing left neglect. That task is given without time constraints and without restrict￾ing eye or head movements