Hai, Benson G. Ong MD; Odderson, Ib R. MD, PhD
Alien hand syndrome is a perplexing and uncommon clinical diagnosis. We report an unusual manifestation of alien hand syndrome in a 73-yr-old man with a right anterior cerebral artery infarct affecting the right medial frontal cortex and the anterior portion of the corpus callosum. We conclude that alien hand syndrome should be considered in patients who present with a feeling of alienation of one or both upper limbs accompanied by complex purposeful involuntary movement.
Alien hand syndrome (AHS) is a perplexing and uncommon clinical diagnosis. It was first described in 1908 by Goldstein 1 in a woman who believed her left hand had a will of its own and experienced involuntary movements such as grabbing and self-choking. Postmortem examination revealed multiple vascular brain lesions involving the right hemisphere and the corpus callosum.1, 2
AHS has been defined as denial of hand ownership and the inability to transfer functions between hemispheres in three patients with corpus callosum tumors.3 Its hallmark is the patient's perception of alienation and loss of control over one or both upper limbs coincident with observable complex goal-directed involuntary movements.4
AHS has been associated with various conditions commonly affecting the corpus callosum, such as contralateral frontal strokes, corpus callosum infarction, anterior communicating artery rupture, corpus callosectomy, combination of a posterior corpus callosum lesion and contralateral thalamic sensory lesion, bifrontal penetrating cerebral injury, callosal tumors,4 and seizures.5 More recently, it has also been described in patients with Alzheimer's disease,6 corticobasal ganglionic degeneration,4 and Cruetzfeldt-Jakob disease.7
We report an unusual case in which a patient with a right hemispheric stroke experienced embarrassing manifestations of AHS in the form of masturbating behaviors, and in which we quantitated side-to-side differences in hand function.
A 73-yr-old, right-handed man was accompanied by his wife to the emergency room because of sudden onset of left-sided weakness. He had poor balance, slurred speech, and mild left facial droop, as well as a history of a right occipital infarct without any residual deficits. His physical examination was remarkable for a left neglect. He had a crural paresis on the left side with less than antigravity strength of the left leg and a left-sided pronator drift. Deep tendon reflexes were normal throughout and plantar responses were flexor in both feet. He did not have any cerebellar ataxia or dysmetria. He was able to stand with maximum assistance, but unable to initiate walking.
A head CT scan showed no hemorrhage or acute infarct; however, it did show an old right occipital lobe infarct. His stroke work-up included a transthoracic echocardiogram and a carotid Doppler that were unremarkable. He was started on aspirin for stroke prophylaxis.
When transferred to the rehabilitation service 4 days later, he was noted to have left upper limb apraxia with involuntary movements. He stated, "my left hand has a mind of his own." He developed a tonic grasp reflex with inability to release. He also had a tendency to reach and grasp onto objects with the left hand, such as the telephone cord or the remote control for the television, and was unable to release despite verbal commands. He would persistently grab his comb or fix the collar of his shirt. He also demonstrated difficulty performing bimanual activities, such as eating. The patient's wife also expressed deep concern when her husband's left hand would publicly expose his genitals and begin masturbating. This occurred on many occasions when the patient was conversing with his caregivers and was confirmed by the authors on their daily rounds. The behavior was never seen to occur through the action of the right hand. The patient also denies any history of excessive self-stimulation, sexual dysfunction, or exhibitionism. During his hospital stay, the patient expressed frustration and dismay when he realized that he was masturbating publicly and with his inability to voluntarily release his grasp of objects in the left hand.
A clinical impression of AHS was made, and magnetic resonance imaging of the brain showed an acute infarct in the medial right frontal lobe in the anterior cerebral artery distribution involving the right anterior cingulate gyrus and the corpus callosum (Figs. 1 and 2). The Jebsen-Taylor Hand Function Test demonstrated a greater impairment of the left hand (Table 1). For the left hand, only one of seven hand tasks was within 2 SD of the mean, compared with three of seven tasks for the right hand.
A Modified Minnesota Rate of Manipulation Test for both hands and an eye-hand coordination test (model VK1200, Eye-Hand Coordinator, Vision Kinetics, Kirkland, WA) also showed that the left hand was significantly slower than the right hand (Tables 2 and 3).
After 3 wk of acute inpatient rehabilitation, the patient was able to walk with a standard walker and negotiate stairs with rails with contact guard assist. He also began to use his left hand for bimanual activities. He was subsequently discharged to home with his family.
One month after discharge, his visual neglect and astereognosis had resolved, but he continued to demonstrate mild agraphesthesia of the left hand. He walked independently without any assistive device. He stated that his left hand "still has a mind of his own and won't turn things loose." The patient's wife reported several occasions when his left hand would still act on its own. The patient once adjusted the thermostat with his left hand without realizing it. Another time, at a bingo game, his left hand unknowingly grabbed a chair and pulled it along as he walked to the bathroom. He was able to release the chair when his wife asked him to open his hand. The patient demonstrated evidence of intermanual conflict. For example, the patient tended to simultaneously bring both hands to his mouth when eating, one holding a piece of chicken and the other holding the fork. However, the patient had ceased performing involuntary public masturbation activities with the left hand.
We have reported a rare case of AHS in a patient with a right anterior cerebral artery infarct primarily affecting the right medial frontal lobe and the anterior portion of the corpus callosum. This patient had an unusual and disturbing manifestation of uncontrolled involuntary genital fondling with the nondominant, apraxic hand and with mirroring hand movements during eating. We have quantitated side-to-side differences of hand function using the Jebsen-Taylor Hand Function Test, the eye-hand coordination test, and the Modified Minnesota Rate of Manipulation Test. However, the significant slowing of the affected limb during voluntary, timed, test-related tasks was not noticeable during automated tasks, such as eating and genital self-fondling. A similar prolonged reaction time on the affected side was demonstrated in a recent motor control study of wrist movements in a patient with AHS. These findings suggest the possibility of the presence of a dexterous "alien" mode of control that can be distinguished from a more clumsy and slow "voluntary" mode of control.
Although alien hand signs vary according to the anatomical location of the lesion, the hallmark of AHS is the patient's perception of alienation from, and loss of control over, one or both upper limbs coincident with observable complex involuntary movements.4 So far, at least two types of AHS have been described. The callosal type, as seen in our patient (lesion involving the corpus callosum with or without frontal damage), is characterized by frequent intermanual conflict and apraxia of the affected limb. The frontal type (lesion involving the left mediofrontal and callosal) is associated with dominant hand grasp reflex, compulsive movements (such as groping), restraining actions, and compulsive manipulation of tools.8
Through the years, AHS has been associated with various diseases, but most commonly with stroke. More recently, it has been reported in patients with corticobasal ganglionic degeneration,4 and Alzheimer's disease,6 and as a postictal manifestation of seizures.5 The anatomical basis of AHS continues to be as fascinating and controversial as when it was first described by Goldstein in 1908.1 Several hypotheses have been suggested, but the most accepted anatomical explanation seems to be a lesion in the medial frontal lobe and surrounding structures-namely, the supplementary motor area (SMA), anterior cingulate gyrus, medial prefrontal cortex, and anterior corpus callosum. The SMA is involved in the control of motor planning and initiation, as well as motor inhibition. In addition to direct projections to the primary motor cortex, the SMA has extensive cortical and subcortical connections, particularly to areas subserving motor control, and is reciprocally connected with the contralateral SMA and primary motor cortex. The left SMA exerts only a unilateral inhibition of the primary cortex, whereas the right SMA exerts both an ipsilateral as well as a contralateral inhibiton of the primary cortices. A lesion involving both the left SMA, as well as the anterior corpus callosum, as seen in patients with frontal type AHS, releases the left primary cortex from both ipsilateral and contralateral inhibition leading to excessive hand grasp reflex, compulsive movements, and manipulation of tools of the right, dominant hand. On the other hand, lesion involving the corpus callosum with or without right frontal damage, as seen in patients with callosal type of AHS, presents with frequent intermanual conflict and apraxia of the left, nondominant hand.8, 9
Having a lesion over the right SMA secondary to an infarct of the medial right frontal lobe, our patient demonstrated alienation and loss of voluntary control of the left hand, which is consistent with the above anatomical explanation. Regional cerebral blood flow studies in normal subjects performing a sequence of finger movements with one hand showed an increase in blood flow in the SMA bilaterally, even when the subject imagined the unilateral movement sequence without actually making any movement.9 However, this hypothesis cannot completely explain the alien hand signs seen in patients with corticobasal ganglionic degeneration.
Masturbation has been associated with temporal lobe epilepsy: however, we are not aware of any reports on stroke precipitating this behavior.10, 11
Although AHS is a rare phenomenon, this condition should be considered in patients who present with a feeling of alienation of one or both upper limbs accompanied by complex purposeful involuntary movement. It must be differentiated from limb neglect and anosognosia, which present with dissociation from the limb as perceived object (i.e., where the limb is not perceived as a part of the "self"), but without involuntary movement and without dissociation from control over purposeful complex action of the affected limb (i.e., where the actions of the limb are perceived as self-generated). Further studies are required to elucidate a definite anatomical explanation that can lead to accurate diagnosis, specific treatment, and rehabilitation of these patients.
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10. Cherian MP: Excessive masturbation in a young girl: a rare presentation of temporal lobe epilepsy. Eur J Pediatr 1997;156:249 Bibliographic Links [Context Link]
11. Jacome DE, Risko MS: Absence status manifested by compulsive masturbation. Arch Neurol 1983:40:523-4 Bibliographic Links [Context Link]
Key Words: Alien Hand Syndrome; Masturbation; Hand Function Tests
