One of my patients with aphasia, a gentleman who had a serious brain hemorrhage more than 10 years ago, recently presented with me to a class of physical therapy students. Because of his profound aphasia, he struggled for words to describe the event that caused his aphasia, an automobile accident that led to a left hemisphere hemorrhage. By pantomiming a driving motion with his arms, he eventually got the idea across. One of the students asked why he gestured: Was it to communicate the idea through pantomime? Was it to help him get words out? He astutely responded that it was both.
Like many individuals with aphasia, this gentleman often resorts to gestures when he is unable to retrieve specific words. Sometimes using a gesture seems to increase the likelihood that he can say the word. As in the gesturing we all do to embellish a message or as we pause to think of words, it is a natural step in communication. Luria (1970) wrote about this phenomenon decades ago, calling the process intersystemic reorganization—using one part of the brain to facilitate increased activity in another part of the brain. Recent research efforts in our lab and others in America and abroad represent renewed interest in the use of gesture to facilitate language recovery in aphasia.
Individuals with severe aphasia often attempt gesturing to communicate. Using gestures is not without complications, however. The brain’s left hemisphere, which controls the ability to retrieve words and construct grammatical sentences, also is the dominant hemisphere for controlling the performance of learned, skilled limb movements. Daily activities in the home and at work, such as writing, cooking, self-care, and manual labor, depend upon stored memories, including the sequences of muscle packages necessary for skilled limb movements. Damage to the left hemisphere can lead to limb apraxia—impairment in the ability to use skilled limb movements.
The typical clinical test that evaluates limb praxis abilities has a patient perform pantomimes to verbal command, including use of transitive tool use gestures (e.g., show me how to use a hammer to pound a nail into the wall), or intransitive symbolic gestures (e.g., show me how you salute). Gesture performance to verbal command is often compared to gesture production for viewed tools or gesture imitation. In general, pantomime to verbal command for transitive gestures tends to be more difficult and, thus, makes detecting limb apraxia more sensitive as compared to other gesture tasks.
Just as the pattern of aphasia varies depending upon what regions of the left hemisphere are disturbed, so too can limb apraxia take different forms. Two types of limb apraxia, described extensively (e.g., Heilman, Watson, & Rothi, 2006), include conceptual apraxia and ideomotor apraxia. Conceptual apraxia represents impairment in conceptual knowledge about tools, the objects they act upon, and the actions required to use them. Patients with conceptual apraxia have difficulty determining the appropriate tool or action needed to complete a given task. In pantomime testing, they may make conceptual errors (e.g., hammering when asked to demonstrate how to use a screwdriver), using no tool (e.g., using their hand to smooth their hair when asked to demonstrate how to use a comb), or providing no response at all.
Ideomotor apraxia, in contrast, represents an impairment related to praxis production knowledge. Although patients with ideomotor apraxia know the tools and actions required, they have difficulty accurately performing the actions. When pantomiming, they make errors in which they move the wrong combination of joints (e.g., fixate at the shoulder rather than the elbow when demonstrating use of a screwdriver, leading to a circular motion rather than a rotating motion), orient their hands in the wrong direction (e.g., use an iron with the palm of the hand oriented perpendicular to the table), or configure their hand poorly (e.g., saluting with the hand in a fist, rather than fingers extended), including use of a body part as tool (e.g., forming the hand in the shape of a tool such as scissors or comb).
Some pantomimes can be unrecognizable, making it difficult to determine whether a patient has conceptual apraxia or severe ideomotor apraxia. The presence of conceptual apraxia and moderate-to-severe ideomotor apraxia can impede the ability of patients with aphasia to use gestures to communicate, as their gestures often are not meaningful or cannot be interpreted readily.
Limb apraxia can cause other problems as well, at times posing a safety risk. The same people who produce unrecognizable gestures may have great difficulty using tools and utensils during daily activities. In a study several years ago, we found that individuals with limb apraxia often have difficulty with routine tasks such as eating (Foundas et al., 1995). Some people had such difficulty using utensils that they gave up and ate their food by shoveling it with a slice of bread or by hand. Others used the wrong objects and implements, such as stirring tea with a knife or sprinkling salt into their tea. When testing one patient in his home for another apraxia study, I observed him struggle to plug in a video recorder and to unlock a deadbolt. Thus individuals with limb apraxia should be closely supervised when using implements, as some apraxic mistakes could place them at risk for injury.
Read the original article at: http://aphasiahelp.blogspot.com.es/2007/07/gestures-and-words-facilitating.html
Anastasia Raymer is a professor in the Department of Early Childhood, Speech Pathology, and Special Education at Old Dominion University in Norfolk, Va. She is chair of the ASHA/American Psychological Association Joint Committee on Interprofessional Relations with Neuropsychology, and is the past coordinator of ASHA Special Interest Division 2, Neurophysiology and Neurogenic Speech and Language Disorders.