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.
Gestural Facilitation of Word Retrieval
The interplay between limb apraxia and aphasia is important to consider as we promote using gestures to enhance communication and language recovery in patients with aphasia. With colleagues at Old Dominion University and the University of Florida, we have engaged in a series of studies examining gestural training to facilitate word retrieval in patients with aphasia. In the training protocol, participants learn to form an appropriate gesture corresponding to a given picture, rehearse the words spoken, and then pair the gesture and spoken word to encourage gestural facilitation of word retrieval. Our study shows that this verbal+gestural training protocol is effective for improving retrieval of both nouns and verbs in patients with varied patterns of aphasia (Raymer et al., 2006). One important issue, however, was to determine the extent to which limb apraxia affected the ability to produce gestures during word retrieval training. Even people with severe limb apraxia improved their ability to produce recognizable gestures. Furthermore, there was no relationship between severity of limb apraxia and treatment effects for word retrieval. Gestural facilitation of word retrieval was effective in individuals with mild and severe limb apraxia. We also found that the effects of verbal+gestural training were as strong as effects of a more conventional treatment method encouraging activation of semantic and phonologic information during word retrieval training.
Several people who participated in our studies did not improve word retrieval with training, whether wirh verbal+gestural or semantic-phonologic training. Most had particularly severe word retrieval impairments. An advantage of verbal+gestural training for these individuals was that many who did not increase their use of spoken words nonetheless demonstrated remarkable improvements in the use of gestures. In fact, the physician of one participant called to say how amazed she was at the improvements her patient had made since participating in our aphasia treatment research. Although the patient did not increase word retrieval abilities, he significantly improved his ability to produce meaningful, recognizable gestures. Furthermore, because all participants in our recent studies participated in videotaped conversations with a spouse or caregiver, we documented that he dramatically increased use of conversational gestures following treatment, more than any other participant in our studies. We suspected that the physician appreciated the improved communication afforded through the patient's increased use of gestures in conversation.
Unfortunately, not all words can be expressed through gestures. Bruce Crosson and colleagues at the University of Florida (Richards et al., 2002) have implemented a different type of word retrieval treatment using non-symbolic limb movements that can be used in training for all types of words, regardless of whether the word has a characteristic pantomime. In their intentional movement training, participants perform a complex non-meaningful movement of the left limb in left space, first in the form of reaching and turning a lever in a box, and later reducing the movement to a circular motion with the left hand, all when paired with rehearsal of spoken target words. The premise of the treatment is that the complex left limb movement engages intact right frontal regions to facilitate activation of that region for word retrieval as well.
The advantage of intentional training is that the complex circular movement can be used quite naturally during conversation, without regard to the topic, whereas pantomime facilitation of word retrieval is limited to concepts that can be expressed by pantomime. Whether it is the rhythm of the intentional movement or the ability of the movement to engage other parts of the brain to improve language recovery is not clear. But these preliminary studies suggest that complex limb movements, not just pantomimes, have the potential to enhance communication attempts in individuals with aphasia and limb apraxia.
Recent discussions of supported communication in patients with aphasia emphasize the use of gesture to enhance communication with conversational partners. Clinicians must bear in mind that severe limb apraxia can hinder gestural communication in some patients with aphasia. Patients may need training to address the limb apraxia directly, which several studies indicate is amenable to treatment. At times people with aphasia insist they want to speak and are unwilling to use gestures, as was one of my patients with severe aphasia. We had to work gently and diligently to help her see that not only could gestures be an effective means to communicate some ideas, but they also could promote retrieval of spoken words. Once she understood that gestures might help her recover verbal abilities, she started to incorporate them in communication attempts.
Table 1: Apraxia errors observed in pantomime testing [PDF]