Apraxia: An Overview
It is undisputed that there is a predisposition in human behavior to imitate and mimic those around us. It is even thought that this ability is endowed in humans from the time of birth. Newborns, for instance, first begin to imitate the gestures of their caregivers. Even adults have a tendency to mimic behaviors or attitudes. One neurological disorder, however, may debilitate this tendency. This is one of the most prominent characteristics of apraxia. According to Rachel Goldman Gross et al, patients suffering from apraxia are plagued with the inability to carry out learned, skilled motor acts despite preserved motor and sensory systems, coordination, comprehension, and cooperation. However, in most cases, this deficit cannot be attributed to elementary motor or sensory systems. Alan Sunderland et al, states that the presence of apraxia is largely attributed to the left hemisphere of the brain, specifically the left inferior parietal lobe. Lesions in the brain do not discriminate and can occur equally to genders, at any age. Natural brain lesions occur as a result of stroke, tumors, head injury, or hemorrhaging. Brain damage can be acquired in a number of ways, including neurosurgery or, more commonly, as a result of a stroke (Ward, pg. 79). In most of the cases I reviewed during my research, apraxia came as a result of the latter, and patients varied in age and gender. Apraxia often occurs simultaneously with aphasia. It has also been reported in cases of Alzheimer’s and Parkinson’s disease. In their book, Apraxia: The Neuropsychology of Action, Leslie J. Gonzalez Rothi and Kenneth M. Heilman explain that more often than not, the term apraxia is used to indicate a disorder of volitional movement where nonvolitional movement is spared. Georg Goldenberg, author of Apraxia: A Cognitive Side of Motor Control, states there are two main distinguishing factors between apraxia and other brain disorders with motor symptoms. First, apraxia impairs both sides of the body equally, even though it is caused by unilateral, left-hemisphere lesions; and, secondly, the severity of the symptoms, or the skillfulness of the movements, depends on the conditions of their execution (Goldberg, pg. 1). The three domains of action that are susceptible to apraxic error are the imitation of gestures, performing meaningful gestures on command, and the imitation or actual use of objects and tools. It is suggested that more restricted lesions will induce selective disturbances of only one or two areas of action and preserve performance in the remaining ones (Goldenberg, 2009). Apraxia is often characterized by postural inaccuracies, which may indicate a broader problem, beyond the motor system, in the retrieval of the spatial and temporal patterns of actions. In addition, this may also suggest that patients with apraxia have lost knowledge about the human body and its position in space. These spatial and postural inaccuracies include the use of the wrong finger, distortions in the orientation of the arm or hand, and/or inappropriate ordering of movement components (Rothi and Heilman, pg. 113). In addition to these spatial and temporal errors, patients with apraxia will often perform body-part-as-object errors in which they use their limb as an object rather than demonstrating how to use the actual object (Gross and Grossman, 2008). Although this is not an exhaustive list of errors made by patients with apraxia, it paints a clear picture of what the disorder may look like. In the following essay, I will give a brief history of apraxia, explore the current models of the disorder, identify the brain mechanisms involved, and provide justification of this knowledge through several tests and studies. Through my best attempt, I will address the daily life and struggles of patients living with apraxia. It is my goal to be coherent of dissociations, double dissociations, and neuroskepticism. I intend to...
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