ناتوانی در ادراک بیماری برای همی پلژی با آگاهی حفظ از نابینایی کامل قشر بدنبال خونریزی داخل جمجمه

Abstract A 51-year-old woman presented with anosognosia for hemiplegia (AHP), neglect, and a complete loss of vision, for which she was almost immediately aware. Neuroimaging studies revealed intracranial hemorrhages in the medial temporal lobes bilaterally, extending back to the occipital cortex, but sparing the calcarine cortex. A large right frontal-parietal hemorrhage which extended to the posterior body of the corpus callosum was also observed. The patient’s vision slowly improved, and by 11 months post onset, formal visual fields revealed improvement primarily in the left upper quadrants only. In contrast, resolution of her AHP occurred between the 26th and 31st day post onset. Awareness of motor impairment was correlated with her ability to initiate finger tapping in her left hemiplegic/paretic hand. During the time she was unaware of her motor deficits but aware of her visual impairments, her dreams did not reflect concerns over visual or motor limitations. The findings support a “modular” theory of anosognosia.

. Introduction Early reports of anosognosia for left hemiplegia were made by von Monakow, Anton, Pick, and Babinski (Papagno and Vallar, 2003). Subsequent group studies on anosognosia for hemiplegia (AHP) noted that this clinical condition is frequently associated with large cerebrovascular accidents (CVAs) typically involving the distribution of the right middle cerebral artery (MCA) (Pedersen et al., 1996 and Orfei et al., 2007). AHP can exist in patients who are aware of other neurological and/or neuropsychological disturbances. Bisiach et al. (1986) demonstrated that AHP could exist in patients with partial visual field loss (e.g., a homonymous hemianopia) who were aware of their visual impairments (and vice versa). This finding led to two theoretical propositions. First, “unawareness of a failure of a particular function betrays a disorder of the highest levels of organization of that function” as initially proposed by Anton (see Bisiach et al., 1986, p. 480). Second, that “awareness” of a given function may be “decentralized and approportioned to the different functional blocks to which it refers” (Bisiach et al., 1986, p. 480). This suggests a “modular” model of anosognosia (Bisiach and Geminiani, 1991). Berti et al. (2005) presented neuroimaging findings supporting this proposition. While the debate continues as to the crucial neural networks responsible for AHP (Prigatano, 2009), lesions involving the right frontal-parietal cortex and insular cortex are commonly associated with AHP (Berti et al., 2005, Karnath et al., 2005 and Vocat and Vuilleumier, 2010). Anton’s syndrome is another classic form of anosognosia (Prigatano, 2009). In this case, the patient is completely cortically blind but unaware of their blindness. The natural course of Anton’s syndrome and its neuroimaging correlates have not been well studied (Prigatano and Wolf, 2010). Yet, Anton’s syndrome is typically associated with bilateral posterior cerebral artery (PCA) occlusions/hemorrhages (e.g., Argenta and Morgan, 1998). We examined and followed a patient who presented with left AHP and complete cortical blindness for 1 year post stroke. Unlike Anton’s syndrome patients, this patient was aware of her blindness. We were interested in determining the neuroimaging correlates of this latter clinical condition and how her vision might change with time. In addition, we monitored the resolution of AHP and its behavioral correlates. If Berti et al.’s (2005) assertion is correct, the patient should become aware of her motor limitations once she is able to carry out an intended motor (finger) movement. If AHP resolves because other associated neurological and neuropsychological disturbances improve (i.e., neglect diminishes and memory gets better), then spontaneous recovery from AHP would not be specifically associated with the ability to initiate movement. Finally, we explored whether the patient’s dreams during the time she presented with AHP, neglect, and awareness of her complete cortical blindness revealed an implicit awareness of her motor deficits, despite her explicit verbal denial of her hemiplegia. It has been suggested that implicit awareness may exist, even when explicit denial of a motor deficit is present (Ramachandran, 1994 and Vocat and Vuilleumier, 2010). Dream material might reveal implicit awareness of an impaired function.

8. Results 8.1. Neuroimaging findings Neuroimaging obtained approximately 10 days post onset of her AHP and cortical blindness revealed abnormal T2 hyperintensity and gyriform enhancement within the medial temporal lobes bilaterally, extending to involve the cortex of the occipital lobes. This enhancement, due to subacute infarction, was adjacent to the temporal optic radiations bilaterally. There was, however, a sparing of the primary visual cortex (Fig. 1). In addition to regions of subacute infarction, postoperative change with enhancement was present involving the paramedian right parietal lobe and the posterior right frontal lobe (Fig. 2). This extended to the vertex. Involvement of the posterior body of the corpus callosum on the right (not shown in Fig. 1 and Fig. 2) was also noted. The insular cortex was spared, as depicted in Fig. 2B. The splenium of the corpus callosum appeared unaffected. A second MRI obtained 4 months after the onset of her neurologic condition showed essentially the same findings. An MRI of the brain conducted 12 months post onset showed sparing of the primary visual (striate) cortex bordering the calcarine fissure with encephalomacia in the right parietal region (Fig. 3). Contrast enhanced T1 weighted axial image from MRI of the brain obtained 10 days ... Fig. 1. Contrast enhanced T1 weighted axial image from MRI of the brain obtained 10 days post onset of AHP and cortical blindness, revealing gyriform cortical enhancement due to infarct within the medial temporal lobes bilaterally, extending to involve portions of the cortex of the occipital lobes. The affected area does include the temporal optic radiations, but there is sparing of the medial occipital lobes including primary visual cortex. Figure options (A) Contrast enhanced T1 weighted axial image from MRI of the brain 10 days post ... Fig. 2. (A) Contrast enhanced T1 weighted axial image from MRI of the brain 10 days post onset of AHP and cortical blindness, revealing an area of mixed gyriform and postoperative enhancement within the paramedial right parietal and posterior right frontal lobe on T1 weighted post contrast imaging. This was seen on other sections from the same exam to extend to the vertex. The primary motor and sensory cortex are involved. Scattered small areas of contrast enhancement represent small regions of white matter ischemia. (B) Contrast enhanced T1 weighted axial image from MRI of the brain 10 days post onset of AHP and cortical blindness. The image section is slightly cephalad to the image of Fig. 2A. Gyriform enhancement due to infarct is again present within the paramedian parietal lobe, however there is sparing of the insula. Figure options High resolution sagittal T2 weighted fast spin echo image from an MRI exam ... Fig. 3. High resolution sagittal T2 weighted fast spin echo image from an MRI exam obtained on a 3 Tesla scanner approximately 365 days post onset of her intracranial hemorrhage. While a large area of encephalomacia is observed in the parietal region, the cortex bordering the calcarine fissure is spared. This was confirmed on other imaging planes and sequences, and in particular, no abnormal FLAIR signal was present in the striate (primary visual) cortex on multiple images not depicted in this figure. Figure options 8.2. Behavioral correlates of recovery of AHP Table 1 summarizes behavioral observations made during the patient’s 20th–31st day post onset of her AHP and cortical blindness. On days 20 and 24, the patient had a complete lack of awareness of her left-sided motor difficulties, as reflected by her Bisiach Score for Anosognosia = 3. During the same time, the patient showed severe left hemispatial neglect. When first asked to take her right hand and touch her left hand, she stopped at the midline (as reflected by Condition A in Fig. 4). During this time she could not move her fingers in her left hand and obtained a 0 score on the Halstead Finger Tapping Test. Right-handed finger speeds were below normal limits for age, gender, and educational background (raw score = 21, T score = 23). At this time, she could recall zero out of three words after a 5–10-min distraction, suggesting severe verbal memory difficulties. She was able to detect tactile stimulation in the right hand, but not the left (see Table 1). Table 1. Clinical course of recovery from AHP and its correlates in a 51-year-old woman who presented with AHP, neglect, and cortical blindness, but aware of her blindness. Time since onset of AHP Bisiach’s score for AHP Motor exploration measure of neglect Halstead finger tapping raw scores/10-sec intervals Number of three words recalled with distraction Tactile perception of hand stimulation RH LH 20 days post 3 Condition A RH = 21 LH = 0 0/3 Yes No 24 days post 3 Condition B RH = 36 LH = 0 1/3 Yes No 26 days post 1 Condition C RH = 29.6 LH = 13.6 2/3 Yes No 27 days post 2 Condition D RH = 24 LH = 12.6 0/3 Yes No 31 days post 0 Condition E RH = 29.4 LH = 13.8 1/3 Yes No 365 days post 0 Condition E RH = 47 LH = 23 3/3 Yes Yesa a Evidence of extinction on bilateral testing. Table options Drawings depicting the patient’s response to the request: “Take your right hand ... Fig. 4. Drawings depicting the patient’s response to the request: “Take your right hand and touch your left arm”. Different responses were recorded during and after the period of AHP (also see Table 1). Figure options At the time she became aware of her hemiplegia (day 26, Bisiach score of 1), she was able to move her fingers in the left hand for the first time (Halstead Finger Tapping mean raw score = 13.6 taps, T score = 19). Just prior to being able to move her left index finger, speed of finger tapping improved in the right “unaffected” hand (see Fig. 5). On the following day (day 27) she showed a slight worsening of her AHP, but her tapping scores were similar. By the 31st day, AHP had resolved (Bisiach score of 0). Her finger tapping speeds showed variability over time, but remained impaired in the left hand over the next 30 days. Her right, “unaffected” hand progressively improved and was within the normal range by 44 days post onset of her initial AHP. One year later, finger tapping speeds were comparable to what was observed when the patient was last tested 59 days post onset of her AHP. Halstead Finger Tapping (raw) scores in both hands before and after the ... Fig. 5. Halstead Finger Tapping (raw) scores in both hands before and after the resolution of the AHP. Figure options Even when AHP resolved, the patient continued to demonstrate neglect, although some improvement was noted (see Fig. 4, Conditions B through E). Also during this time when eating she would not explore the left side of her plate for food. Verbal memory deficits also persisted after AHP resolved (see Fig. 4 and Table 1). Before and after AHP resolved, the patient continued to report complete loss of vision. At no time was there evidence of an aphasic disturbance. She generally was oriented to time and location within 20 days of her hospital stay. She was able to engage in conversation and answered all questions that were raised by the examiners. During this time she could detect tactile sensation of the right hand, but not the left.