Globus Pallidus Lesions Associated with High Mountain Climbing

Acute mountain sickness (AMS) occurs commonly in hikers who are rapidly exposed to high altitude environments. Despite the numerous reports of AMS, few studies have reported pallidal lesions associated with altitude sickness. A previously healthy 49-yr-old Korean patient, after ascent to 4,700 m, suffered symptoms consistent with AMS. After returning home, the patient showed changes in personality characterized by abulia, indifference, and indecisiveness. T2 weighted brain magnetic resonance imaging showed high signal lesions involving bilateral globus pallidus. Our case suggests that globus pallidus injury should be included in the differential diagnosis of patients with personality or cognitive change after recovery from AMS.

Hanja Alexia with Agraphia After Left Posterior Inferior Temporal Lobe Infarction: A Case Study

Korean written language is composed of ideogram (Hanja) and phonogram (Hangul), as Japanese consists of Kanji (ideogram) and Kana (phonogram). Dissociation between ideogram and phonogram impairment after brain injury has been reported in Japanese, but few in Korean. We report a 64-yr-old right-handed man who showed alexia with agraphia in Hanja but preserved Hangul reading and writing after a left posterior inferior temporal lobe infarction. Interestingly, the patient was an expert in Hanja; he had been a Hanja calligrapher over 40 yr. However, when presented with 65 basic Chinese letters that are taught in elementary school, his responses were slow both in reading (6.3 sec/letter) and writing (8.8 sec/letter). The rate of correct response was 81.5% (53 out of 65 letters) both in reading and writing. The patient's performances were beyond mean-2SD of those of six age-, sex-, and education-matched controls who correctly read 64.7 out of 65 and wrote 62.5 out of 65 letters with a much shorter reaction time (1.3 sec/letter for reading and 4.0 sec/letter for writing). These findings support the notion that ideogram and phonogram can be mediated in different brain regions and Hanja alexia with agraphia in Korean patients can be associated with a left posterior inferior temporal lesion.

Horizontal versus Vertical Reading in Neglect Dyslexia: A Case Study

BACKGROUND: Neglect dyslexia is a type of neglect syndrome, in which patients with unilateral hemisphere injury omit or misread the contralateral side of a text or the initial letters of a word. Hangul can be arrayed vertically (vertical reading, VR) as well as horizontally (horizontal reading, HR). Thus, HR and VR can be differentially affected in neglect dyslexia. We conducted an experiment in a 66 year-old woman who suffered from neglect dyslexia after a right cerebral infarction. We compared HR with VR in terms of error frequencies and patterns. METHODS: Stimuli for neglect dyslexia consisted of 227 words. The 227 words were written horizontally or vertically (total 554 words) and were pre-sented in random order. The patient was asked to read the words and the examiner recorded the patient's responses and reaction times. RESULTS: The differences in HR and VR were as follows: 1) the error frequency in HR (59.0%) was higher than the error frequency in VR (20.3%), 2) the most frequent error in HR was syllabic deletion (79.1%) whereas phonemic substitution (89.1%) predominated in VR, 3) the error rate was highest at the first syllabic position in HR whereas no position effect was noted in VR. CONCLUSIONS: Patients with neglect dyslexia make less error in VR than in HR. The neural processing of HR may be different from that of VR. VR may be an alternative reading strategy that may be useful during the recovery stage of neglect dyslexia.

The Reliability and Validity of the Korean Instrumental Activities of Daily Living (K-IADL)

BACKGROUND: The measurement of functional disabilities in patients with dementia is one of the essential parts of evaluation for dementia from the viewpoint of diagnosis and therapeutic intervention. Nevertheless, few standardized scales for the instrumental activities of daily living (IADL) are available in Korea. The purpose of this study was to test the reliability and validity of the Korean IADL (K-IADL). METHODS: K-IADL is comprised of 11 items that were selected by the Representative Committee of the Korean Dementia Research Group. These include: (1) shopping, (2) mode of transportation, (3) ability to handle finances, (4) house keeping, (5) preparing food, (6) ability to use a tele-phone, (7) responsibility for own medication, (8) recent memory, (9) hobbies, (10) watching television, and (11) fixing around the house. K-IADL was administered to informants of 114 dementia patients and age and sex matched 106 con-trols. The informants rated each item as follows: 0=normal, 1=with some assistance, 2=with much assistance, 3=unable to do, NA=not applicable. RESULTS: Internal consistency (Cronbach's alpha=0.96) and the test-retest reliability(r=0.94) of K-IADL were significant. A principle component factor analysis extracted a single factor that accounted for 70.3% of the total variance (Eigenvalue: 7.74), and K-IADL was correlated significantly with other general cognitive indices, demonstrating good validity. With a cut-off point of 0.43, the K-IADL had a sensitivity of 83% and a specificity of 82% in the diagnosis of dementia. CONCLUSIONS: Our results showed that K-IADL could be a reliable and valid tool for the quantification of functional disabilities of Korean dementia patients.

Is Brain Biopsy Rational in Shunt Operation of Normal Pressure Hydrocephalus in Elderly?

Early detection of AD in its initial or preclinical stage has become increasingly important. We report a 73-year-old woman who was confirmed to have AD by a cortical biopsy performed concomitantly during a shunt operation for hydrocephalus. The triads of hydrocephalus improved after the operation, as did follow-up neuropsychological and FDG-PET findings. However, 2.5 years after the operation, the patient developed cognitive declines with abnormal behaviors, which was considered to be an evolved form of AD from the preclinical stage.

Primary Progressive Amnesia 3 Cases: a Case Study

BACKGROUND: Isolated amnesia without dementia results from various etiologies. When caused by degenerative etiol-ogy, it is recognized as a subtype of Alzheimer's disease (AD) and was termed progressive isolated amnesia or primary progressive amnesia (PPAm). Patients with PPAm have rarely been reported. We describe neuropsychogical and neu-roimaging findings in 3 patients with PPAm. METHODS: Patient 1 (M/74) showed progressive amnesia for 8 years and then developed probable AD. Patient 2 (M/76) and 3 (F/69) showed severe progressive amnesia without dementia for 9 years. Neuropsycholgical evaluations were conducted 3 times in each patient at 1 to 4 year interval. Hippocampal vol-ume was measured by a manual tracing in 1.6 mm thick coronal MRI slices which was obtained perpendicular to the long axis of the hippocampus. RESULTS: Neuropsychological tests revealed verbal and nonverbal memory loss with preservation of attention, language, praxis, visuospatial and frontal-executive functions. Right and left hippocampal vol-umes for patient 1, 2 and 3 were 1580.46/1586.38, 682.96/609 and 1152.84/1272.50 mm3 respectively, a result indica-tive of severe hippocampal atrophy. CONCLUSIONS: Neuropsychological profiles and clinical course of our patients fur-ther support the view that PPAm results from degenerative etiology. Severe atrophy of the hippocampus with relative preservation of other association cortices suggest that PPAm may be another focal cortical atrophy syndrome involving medial temporal region.

Neuropsychological and Neuroimaging Findings of Semantic Dementia

BACKGROUND: Semantic dementia (SD) is a temporal variant of frontotemporal lobar degeneration (FTLD), which is characterized by naming difficulty, decreased comprehension of words, prosopagnosia and object visual agnosia. We report clinical features, neuropsychological and neuroimaging findings of 4 patients with SD. METHODS: Of 55 patients diagnosed as having FTLD between Jan 1995 and May 2001 at Samsung Medical Center, four patients fulfilled the diagnostic criteria of SD proposed by consensus on FTLD diagnostic criteria. We investigated their clinical features such as presenting symptoms and abnormal behaviors, neuropsychological and neuroimaging findings. Neuropsychological tests included the Seoul Neuropsychological Screening Battery, the Korean-version of Western Aphasia Battery and Hanja reading and writing. All patients underwent brain MRI and FDG-PET. RESULTS: All of the patients showed naming difficulty as a presenting symptom. Language assessments showed severe naming and compre-hension difficulties with preserved fluency and repetition, which were compatible with transcortical sensory aphasia. Whereas Hangul reading aloud and writing were intact, three patients were impaired at Hanja reading and writing. Other neuropsychological tests were remarkable for prosopagnosia, object visual agnosia and memory loss. Brain MRI showed asymmetric temporal atrophies, mainly left antero-inferior temporal cortices. FDG-PET also showed hypome-tabolism in bilateral anterior temporal lobes, more severe on the left. CONCLUSIONS: Our SD patients had characteristic neuropsychological and neuroimaging findings, which can be differentiated from other neurodegenerative diseases. We also found Hanja alexia and agraphia in SD patients, which has not been reported yet.

Retrograde Amnesia Following Anterior Thalamic Infarction

BACKGROUND: Retrograde amnesia (RA) refers to the failure to recall events that occurred before a brain injury. RA is known to be associated with brain lesions involving the hippocampus, entorhinal cortex and the frontal lobe. Anterior thalamic lesion often causes anterograde amnesia but rarely causes RA. The aim of the present study is in two parts . First, we discuss the neuroanatomical perspectives of RA based on our case with severe RA after a right anterior thalamic infarction. Second, we introduce a test for RA termed the "Korean Public Events Recall Test (K-PERT)", which was developed based on famous Korean public events from 1966 to 1997. METHODS: A 62-year-old woman with transient RA after a left anterior thalamic infarction 4 years ago presented severe and persistent RA following a right anterior thalamic infarction. We followed up the patient with neuropsychological tests. We also performed the K-PERT on the patient as well as on 14 women of the same age and education. RESULTS: Neuropsychological tests showed severe impairment in autobiographical memory with frontal lobe dysfunction. On K-PERT, the normal controls scored 13.7 +/- 3.7 in recall and 21.2 +/- 3.1 in recognition out of a maximum score of 30, whereas the patient obtained only 3/30 and 4/30, respectively. CONCLUSIONS: In our case, RA might have resulted from damage to the pathway that retrieves old memories, which are stored in the frontal lobe. Thus, anterior thalamus might be viewed as the gate of memory engram. Further studies are needed to elaborate the usefulness of K-PERT as an objective tool for investigating remote memory.