Autotopagnosia is a rare neuropsychological syndrome characterized by disordered localization of body parts. Reports remain scarce and the cognitive mechanisms underlying this syndrome are not fully understood. We describe the case of a 65-year-old Japanese man whose clinical and neuropsychological profiles and neuroimaging findings supported a diagnosis of probable Alzheimer's disease. Notably, he had episodic memory deficits and visuospatial impairment without aphasia, along with Gerstmann syndrome and marked autotopagnosia. Neuropsychological examinations assessed body-part knowledge and processing, combining pictorial representations, spoken instructions, and tactile input with pointing and naming responses; single-case comparisons were benchmarked against age-matched, cognitively healthy adults (n = 20). The patient could name body parts and retain general knowledge and visual recognition of them, yet consistently failed to localize those parts on whole-body stimuli: his own body, another person's body, and a full-body diagram. Language-only probes of inter-part spatial relations were impaired, whereas non-spatial definitions were preserved. This cross-modal profile is not attributable to a single sensory modality or language/motor factor, nor is it readily explained by accounts invoking failures to map visual/somatosensory inputs to body-part location or the primary disruption of an egocentric, multisensory body schema. Instead, it is most consistent with a modality-independent disruption of body-part localization knowledge, i.e., a high-level body-centered spatial map linking body-part labels to their canonical positions on the human body. Our findings suggest that autotopagnosia can be parsimoniously unified through this mechanism. These observations underscore the need for standardized, modality-diverse examinations to clarify the mechanisms underlying this rare clinical phenomenon.

We report a patient with posterior cortical atrophy (PCA) who manifested as agraphia for kanji and statokinetic dissociation (Riddoch phenomenon). A 52-year-old, right-handed woman complained that beginning at age 50, she could write only kana (a phonographic script) but not kanji (a morphographic script). She could not write even her own name in kanji. Neuropsychologic examinations disclosed kanji-dominant agraphia, acalculia, right-left disorientation, finger agnosia, constructional apraxia, and simultanagnosia. Many of these, including agraphia, are components of Gerstmann syndrome. She manifested no aphasia or alexia, while not only writing but also copying of kanji was impaired. Speech functions, behavior, and personality were relatively spared. The patient also displayed statokinetic dissociation (Riddoch phenomenon): kinetic Goldmann fields were normal, but static Humphrey visual fields showed an incongruous right homonymous hemianopsia. MRI showed atrophy of the left parietal lobe. 99mTc ethyl cysteinate dimer (ECD) single-photon emission computed tomography (SPECT) showed hypoperfusion , predominantly in the left hemisphere and especially left the parietal lobe . These clinical and neuroradiologic findings are consistent with PCA. In patients with PCA, suspected incomplete homonymous hemianopsia should be confirmed with a Humphrey visual field test. Ishihara pseudoisochromatic plates may not be reliable; color vision should be checked using the panel D-15 test.

Brain abscesses often present with headache, altered state of consciousness, and/or fever. Depending on their location, they may present with other clinical manifestations. Gerstmann syndrome, characterized by acalculia, agraphia, digital agnosia, and right-left confusion, occurs classically with lesions of the dominant parietal lobe. A 50-year-old immunocompetent female presented to the emergency department with seizures, headaches, and visual hallucinations. Brain magnetic resonance imaging revealed a right space-occupying lesion causing a mass effect consistent with a brain abscess. The patient was promptly started on ceftriaxone and metronidazole, followed by successful surgical drainage of the abscess. Cultures confirmed an infection with Streptococcus intermedius. During follow-up, the patient exhibited symptoms of acalculia, agraphia, digital agnosia, and right-left confusion, consistent with Gerstmann syndrome, attributed to significant postoperative edema. Although these cognitive sequelae showed partial improvement over time, they substantially impacted the patient's functional abilities and psychological well-being. Gerstmann syndrome is traditionally associated with lesions in the left angular gyrus. However, in our case, the lesion was located on the right side. Interestingly, there is only one other documented case of Gerstmann syndrome linked to a brain infection in the medical literature. Furthermore, our patient presented without the typical risk factors for brain abscesses, such as immunosuppression, an identifiable infectious source, or epidemiological connections commonly associated with this pathogen. This case highlights a rare and impactful condition, significantly affecting the patient's quality of life while also contributing valuable insights to the understanding of this uncommon neurological syndrome.

Hyperglycemic hyperosmolar nonketotic syndrome (HHNS) is a complication of type 2 diabetes mellitus that can progress to coma and death if left untreated. Focal hyperglycemic seizures are still an uncommon but noteworthy association of HHNS and most commonly involve the occipital and parietal lobes. Gerstmann syndrome, also called angular gyrus syndrome, consists of a tetrad of finger agnosia, acalculia, left-right disorientation, and agraphia that is usually accompanied by aphasia and most commonly presents in parietal lobe pathology. Here we report a case of a 50-year-old right-handed male with complaints of focal right-sided upper limb and facial seizures and findings of acalculia, finger agnosia, left-right disorientation, semantic aphasia, and loss of comprehension. Laboratory reports suggested HHNS seizures that presented clinically as Gerstmann syndrome. Magnetic resonance imaging (MRI) of the brain revealed dominant (left in our case) parietal lobe pathology. Although it is understood that HHNS is linked with focal neurological deficits, the exact mechanism by which this happens is still unknown, and Gerstmann syndrome associated with hyperglycemic seizures is still underreported, necessitating additional research.