Word Memory Test Profiles in Two Cases with Surgical Removal of the Left Anterior Hippocampus and Parahippocampal Gyrus

摘要

One principle underlying the use of the Word Memory Test (WMT) as an effort test is that with good effort, recognition scores above the cutoffs will be observed. However, to understand the limits of effort testing, it is necessary to study people known to have severe impairment and significant neuropathology involving memory structures. Goodrich-Hunsaker and Hopkins (2009) reported that three amnesic patients with bilateral hippocampal damage had severely impaired free recall of the WMT word list but passed the recognition subtests of the WMT, which are often called effort subtests. We tested two patients with surgical resections in the left anterior temporal region to treat chronic intractable epilepsy; both patients had suffered postoperative strokes. Patient A was a 15-year-old boy and Patient B was a 58-year-old woman. Despite destruction of the left anterior hippocampus and the parahippocampal gyrus and despite impairment of free recall, both cases passed the easy WMT effort subtests. These data reinforce previous findings that people with severe impairment of free recall will score much higher on the verbal recognition memory subtests than on the more difficult memory subtests. Even severe memory impairment and/or removal of hippocampal areas do not necessarily lead to failure on the easy WMT recognition subtests.