Visual hallucinations have been reported in a variety of pathological states, including Charles Bonnet Syndrome (visual hallucinations of the blind), migraine headache, Lewy body dementia, Parkinson's disease, narcolepsy, delirium tremens, schiz- ophrenia, use of hallucinogenic drugs, and peduncular hallucinosis (Manford & Andermann, 1998). Peduncular hallucinosis (PH) is characterized by complex visual hal- lucinations (CVH); the images are detailed, colored, and animated. The content of the imagery is stereo- typed, often limited to people or ani- mals in miniature proportions (Danziger, Meary, & Mercier, 1997). Most cases of PH are caused by ischemic insults (Liedholm, Ange- gard, & de Flon, 1999); the imagery starts a few days after the stroke. Other etiologic factors reported in the literature include neoplastic lesions (Miyazawa, Fukui, & Otani, 2001; Navdi & van Dellen, 1994) or surgical manipulation of the brainstem Questions or comments about this article may be directed to: Mitra Assadi, MD, by phone at 856/342-2445 or by e-mail at assa di-mitra@cooperhealth.edu. Dr. Assadi is an assistant professor of neurology at the University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden (UMDNJ/RWJMS), Cooper Health System, in Camden, NJ. Susan Baseman, MS APRN BC, is the asso- ciate program director for neurosciences at UMDNJ/RWJMS, Cooper Health System. Daniel Hyman, DO, is an assistant profes- sor of medicine at UMDNJ/RWJMS, Coop- er Health System: Copyright ©2003 American Association of Neuroscience Nurses 0047-2606 /03/3503/ 00175$5.00 Clinical Corner Roxanne Pickett-Hauber, Section Editor Tc SPECT Scan in a Patient with Occipital Lobe Infarction and Complex Visual Hallucinations Mitra Assadi, Susan Baseman, Daniel Hyman (Kumar & Kaur, 2000; Quasho, Lunar- di, & Mancinelli, 1998; Tasukamoto, Matsushima, & Fujiwara, 1993). Regardless of etiology, there is involve- ment of the deep gray matter, specifi- cally, the brainstem or the thalami. Alterations in the sleep-wakefulness cycle also have been observed with PH, more so in patients with brain- stem lesions. The hallucinations are present on and off during wakefulness and peak in the evening (Manford & Andermann, 1998). Patients are fully aware of the unreal nature of the visu- al imagery. In most cases, complete resolution of the hallucinations occurs in few days. Peduncular hallucinations were described by Lhermitte (1922) in the beginning of the last century. He had observed frequent involve- ment of the midbrain, which led to selecting the term peduncular hal- lucinosis. This was a_ simple descriptive terminology implying the neuro-anatomical correlate for this condition. Typically, PH is associated with a normal visual cortex. On the other hand, similar clinical manifestations have been described, albeit rare, in patients with occipital lobe infarction. The anatomical substrate for CVH is unknown. Manford and Ander- mann (1998) attribute the phenome- non to faulty cortical stimulation due to abnormal visual input or process- ing (the cortical release theory). They reviewed the occurrence of CVH in a number of conditions, including PH, epilepsy, narcolepsy-catalepsy syn- drome, and others. These various pathologies all have in common some mechanism that could potentially Journal of Neuroscience Nursing, June 2003 ¢ Volume 35, Number 3 disrupt thalamocortical projections. Presumably, this results in a loss of inhibition at the levels of the visual association cortex and causes the hal- lucinations. Manford and Ander- mann postulated that the occurrence of strikingly similar hallucinations from these apparently diverse patho- logical conditions may be due to this abnormal cortical release phenome- non and the resulting loss of cortico- cortical inputs and effects on the reticular activating system. The following case report describes a patient with occipital lobe infarction and CVH and provides radiographic evidence for the cortical release theory by reporting increased uptake in the right temporal lobe on the brain Te SPECT (technetium single-photon emission computed tomography) scan. Case Report This 84-year-old woman was admitted to the hospital due to con- gestive heart failure. She underwent surgery for aortic valve replacement and coronary bypass. She was in intermittent atrial fibrillation and was anticoagulated. On the seventh day after her operation, she report- ed complex visual hallucinations. She described seeing dwarfs on the left side of the room only. The images were colored, animated, and extremely realistic. The hallucina- tions were present on and off dur- ing waking hours. She found them entertaining and was fully aware of their unreal nature. Sleep distur- bances were denied. Neurology consultation was per- formed, and the examination demon- strated normal higher cortical function 175 as well as normal ocular motility and pupillary reactions. A new left-sided hemianopia was documented. No sensory or motor deficits were found. There were no reflex asymmetries. A computed tomography (CT) scan of the brain showed a hemorrhagic stroke involving the right calcarine cortex (Fig 1). A Te SPECT scan demonstrated decreased uptake in the right calcarine cortex. In addition, an area of increased uptake was demon- strated in the right temporal lobe (Fig 2). The hallucinations diminished rapidly and subsided in 72 hours. Discussion Tc-99m_ ethylcysteinate dimer (ECD) SPECT imaging is a form of functional imaging that has the potential to assist the clinician in localizing brain abnormalities associ- ated with a variety of neurological disorders based on changes in cere- bral blood flow. The brain uptake of Tc-99m ECD is proportional to Fig 1. Head CT shows evidence of hemorrhagic stroke in the right calcarine cortex. 176 regional blood flow. Lorberboym, Lampl, Gilad, and Sadeh (2002) reported a limited case study of nine patients with visual hallucinations who were evaluated using Te SPECT imaging. They found that seven of the nine had increased cerebral per- fusion as seen on Te SPECT scan in one or more regions of the brain. Fol- low-up imaging after 1 week in these patients showed significant or com- plete resolution of the perfusion changes noted on the initial scan. This correlated to a partial to com- plete resolution of the hallucinations. They concluded, and the current case study also suggests, that brain imag- ing using Te SPECT may be useful in identifying brain-blood flow abnor- malities associated with visual hallu- cinations in some subgroups of patients, including those with stroke. We have demonstrated abnormal activation of the right temporal lobe in this patient with CVH. This find- ing can be considered as supportive evidence for the cortical release theo- ry. The right temporal lobe is crucial for visual memory. We have acquired this knowledge by studying tempo- ral lobe epilepsy (TLE; Barr, 1997), temporal lobectomy for TLE (Morris, Abrahams, & Polkey, 1995; Nunn, Polkey, & Morris, 1998), and Wada testing. Deficits in visual and spatial memory in patients with right mesiotemporal sclerosis are well doc- umented (Gleissner, Helmstaedter, & Elger, 1998). We propose that activa- tion of the right temporal lobe, as one of the areas closely involved with the visual memory, might be the respon- sible mechanism for CVH. This patient reported experienc- ing visual hallucinations in the hemianopic field only. This phe- nomenon has rarely been reported in the literature (Manford & Ander- mann, 1998). The mechanism for lat- erality of the hallucinations remains unclear. Theoretically, this could be explained by the fact that the stroke Fig 2. An area of increased uptake in the region of the right temporal lobe is demonstrated on Te SPECT scan. Journal of Neuroscience Nursing, June 2003 ¢ Volume 35, Number 3 and subsequent metabolic changes in the temporal lobe involved the right side of the brain. Implications for Care Important implications for nursing can be drawn from this case report. In elderly hospitalized patients, halluci- nations and other visual disturbances are often attributed to hospital psy- chosis, dementia, drug reaction, or simple confusion without a full eval- uation of organic factors. Further, restraints (physical or chemical) may be used based on an assumption that the hallucinating patient is likely to act upon the hallucinations, resulting in injury to herself or others. When a patient reports hallucina- tions, it is incumbent upon the nurse to perform a detailed assessment, including a full physical and neuro- logical assessment. A thorough neu- rological examination will elicit key findings that assist in the correct diagnosis of the problem and help guide appropriate nursing care. The neurological assessment of this patient with complex visual hal- lucinations revealed normal higher cortical function and a new left-sided hemianopia. Another key parameter assessed was the patient's impres- sion of, and response to, the halluci- nations. The patient was aware of the unreal nature of the hallucina- tions, and she seemed unafraid and unlikely to respond inappropriately to them. When these findings were assessed in conjunction with the results of the CT and Te SPECT scans, it became clear that there was an organic, neurological basis to the problem of the complex visual hallucinations. The nurse must accurately assess all reported symptoms and ensure that patient care is based on objective assessment findings, rather than on assumptions that might be biased due to the age of the patient or the unusual nature of the reported symp- tom. This case report highlights the need to suspect neurological distur- bances as possible organic causes of hallucinations and to use all the tools of neurological assessment and neu- roradiological imaging available to correctly diagnose the condition and appropriately manage the patient. Summary We have described a patient with occipital lobe infarction and CVH in the hemianopic field. Increased uptake in the right temporal lobe was documented on the brain Te SPECT scan. We propose that activation of this area might be the underlying mechanism for visual hallucinations. This case report is a clear example of the wide spectrum of the clinical manifestations in stroke victims. We also emphasize the importance of educating the medical staff about the organic basis for human behavior. References Barr, W.B. (1997). Examination of the right temporal lobe's role in nonverbal memo- ry. Brain Cognition, 35, 26-41 Danziger, N., Meary, E., & Mercier, B. 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Peduncular hallucinosis following a transoral odontoidectomy for cranio- vertebral junction malformation. Journal of Neurosurgical Science, 42, 47-49. Tasukamoto, H., Matsushima, T., & Fujiwara, S. (1993). Peduncular hallucinosis following microvascular decompression for trigeminal neuralgia. Surgical Neurology, 40, 31-34. 177