Targets. Anosognosia for hemiplegia (AHP) is usually secondary to right-hemisphere damage and involves the inability of patients to recognize and admit their hemi-paralysis1. This negatively impacts on rehabilitation (due to lack of motivation) and outcome2. There is a debate on whether AHP affects body and self-representations or motor planning and monitoring2. Although action observation modulates the AHP symptoms3, the relationship between unawareness and action representation is not clear. We explored this topic, by investigating the relationship between motor awareness and representation of the temporal duration of actions. Materials. 60 people participated in the study; 25 hemiplegic patients: 10 right brain damaged with left hemiplegia (RBD), 6 RBD suffering from anosognosia (AHP) and 9 left brain damaged with right hemiplegia (LFB). 35 healthy subjects (age and education-matched) participated as controls. A neuropsychological assessment controlled for neglect, apraxia, memory and comprehension deficits In the experimental task (Action Time Estimation–ATE) some videos of actions with objects were presented in two conditions, showing: i) a hand performing actions (with effector); ii) objects moving without effector. In two control tasks, videos showed a ball moving toward a bar (Movement Time Estimation–MTE) or a still circle (Static Time Estimation–STE). The durations of the videos were 3000ms, 4500ms, 6500ms. Method. In all the tasks, participants were asked to watch each video and estimate its duration by means of a 0-8 seconds scale. For each trial and subject, the ratio between the estimation-duration and the real duration ((estimation-real duration)/(real duration)) was calculated. Results. In the ATE, when the hand was shown, AHP patients performed like controls, while RBD and LBD patients underestimated the action duration (p<0.001). In contrast, both RBD and AHP patients’ performances did not differ from controls’ in control tasks. LBD group significantly underestimates the duration of all the tasks. Discussion. These results indicate that awareness of motor deficits modulates the temporal representation of actions. In fact, hemiplegic aware patients tend to perceive actions performed by others as faster than how these are. Viceversa, AHP did not show this pattern, indicating that unawareness prevents the possibility to update action representations in accordance with the current body-state and abilities. Control tasks exclude the possibility of a general time estimation deficit, which could be instead present in the LBD group. Conclusions. Our results indicate a reciprocal interaction between body and action representations, which is crucial for successful motor rehabilitation programs.
The effects of motor awareness on the temporal representation of the action / Pacella, Valentina; Maria, Bà; Gobbetto, Valeria; Smania, Nicola; Volpe, Daniele; Avesani, Renato; Moro, Valentina. - (2019). (Intervento presentato al convegno 7th scientific meeting of the Federation of the European Societies of Neuropsychology tenutosi a Milan).
The effects of motor awareness on the temporal representation of the action
Valentina Pacella;Maria Bà;Valeria Gobbetto;Daniele Volpe;
2019
Abstract
Targets. Anosognosia for hemiplegia (AHP) is usually secondary to right-hemisphere damage and involves the inability of patients to recognize and admit their hemi-paralysis1. This negatively impacts on rehabilitation (due to lack of motivation) and outcome2. There is a debate on whether AHP affects body and self-representations or motor planning and monitoring2. Although action observation modulates the AHP symptoms3, the relationship between unawareness and action representation is not clear. We explored this topic, by investigating the relationship between motor awareness and representation of the temporal duration of actions. Materials. 60 people participated in the study; 25 hemiplegic patients: 10 right brain damaged with left hemiplegia (RBD), 6 RBD suffering from anosognosia (AHP) and 9 left brain damaged with right hemiplegia (LFB). 35 healthy subjects (age and education-matched) participated as controls. A neuropsychological assessment controlled for neglect, apraxia, memory and comprehension deficits In the experimental task (Action Time Estimation–ATE) some videos of actions with objects were presented in two conditions, showing: i) a hand performing actions (with effector); ii) objects moving without effector. In two control tasks, videos showed a ball moving toward a bar (Movement Time Estimation–MTE) or a still circle (Static Time Estimation–STE). The durations of the videos were 3000ms, 4500ms, 6500ms. Method. In all the tasks, participants were asked to watch each video and estimate its duration by means of a 0-8 seconds scale. For each trial and subject, the ratio between the estimation-duration and the real duration ((estimation-real duration)/(real duration)) was calculated. Results. In the ATE, when the hand was shown, AHP patients performed like controls, while RBD and LBD patients underestimated the action duration (p<0.001). In contrast, both RBD and AHP patients’ performances did not differ from controls’ in control tasks. LBD group significantly underestimates the duration of all the tasks. Discussion. These results indicate that awareness of motor deficits modulates the temporal representation of actions. In fact, hemiplegic aware patients tend to perceive actions performed by others as faster than how these are. Viceversa, AHP did not show this pattern, indicating that unawareness prevents the possibility to update action representations in accordance with the current body-state and abilities. Control tasks exclude the possibility of a general time estimation deficit, which could be instead present in the LBD group. Conclusions. Our results indicate a reciprocal interaction between body and action representations, which is crucial for successful motor rehabilitation programs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
