Liepmann was the first to actually conduct tests on these patients in his laboratory. These tests are known as multiple-object tasks or MOT. Each task requires the patient to use more than one object; the researcher describes a task to the patient and asks them to execute that task as described. Liepmann gave the patients all the necessary articles, such as a candle and a matchbox, which were placed before the patient. He then observed the patients to see how they interacted with each object. In the case of the matchbox, one patient brought the whole box up next to the wick, instead of just one match. Another opened the box and withdrew a match, then brought it to the wick unlighted. Still another patient struck the candle against the striking surface on the matchbox. Thus Liepmann was able to witness the discontinuity of the patients' actions with respect to everyday objects and to categorize the errors that the patients made, namely: mislocation of actions, object misuse, omissions, perplexity, and sequence errors. Even though afflicted persons are unable to correctly perform simple tasks using multiple items as provided, they are able to accurately identify the objects involved in simple tasks. For example, they are able to match a given sequence of photographs with the correct label, such as: the process of making coffee, buttering bread, or preparing tea. These patients are also able to successfully identify objects when a researcher verbally describes the function of the tool. Another test involves matching the appropriate object with its function. Finally, the fact that patients can identify the actions of a given tool from a sequence of photographs, shows that they completely understand object usage. The deficit is therefore not that patients lack the knowledge of how to use an object; they fully understand the function of each tool. Rather, the problem lies in that, when they attempt to interact with the tools (in a multiple-object task) in order to execute those functions, that execution is flawed.
Ideational apraxia
Paragrammatism
Musical anhedonia
Body substance isolation
Social-emotional agnosia
Agrammatism
Homicidal ideation
Emotional detachment