A 63-Year-Old Man With Progressive Visual Symptoms

Abstract

A 63-year-old man presented with a 4-year history of insidious onset and gradual progression of visual symptoms consisting of difficulty with locating objects within a complex visual scene (unable to see things "right in front of him," especially with clutter), impaired navigation while driving, and inability to perform complex motor tasks under visual guidance (ie, unloading the dishwasher). He subsequently developed alexia, agraphia, and acalculia. He was diagnosed as having a right homonymous hemianopsia by a neuroophthalmologist after he was hit by a truck from the right side while riding a bicycle. He later hit a parked car on his right while driving. His memory in daily life was intact. Within the first year of symptom onset, he developed mild language impairment characterized by word finding difficulty, anomia, and eventually mild comprehension deficits with intact repetition and speech production, consistent with transcortical sensory aphasia.His initial neurological examination findings were significant only for a right homonymous hemianopsia, with a notable absence of parkinsonism or asymmetric motor findings. There was no contributory medical history or systemic symptoms.His father developed dementia at age 52 years and died at age 57. The clinical diagnosis was Alzheimer disease (AD), but no autopsy was performed. There was no other significant family history including no history of Parkinson disease or amyotrophic lateral sclerosis.Neuropsychological testing performed 4 years after symptom onset revealed relatively intact memory function with impairments in visuospatial processing including impaired performance on Wechsler Adult Intelligence Scale, Third Edition Matrix Reasoning and clock drawing. There was also evidence of impaired phonemic fluency and word retrieval with intact semantic memory. Subsequent neurological examination findings revealed Bálint syndrome (simultanagnosia, oculomotor apraxia, and optic ataxia) with transcortical sensory aphasia, bilateral limb apraxia (right>left) with cortical sensory loss, and asymmetric rigidity of the right arm and leg.

Executive dysfunction contributes to verbal encoding and retrieval deficits in posterior cortical atrophy

“…Although much of the literature examining clinical deficits in PCA has focused on visual and visuospatial deficits, a few reports have included descriptions of working memory, executive function, and episodic memory deficits in this population (Ahmed et al, 2016; Crutch et al, 2013; Gardini et al, 2011; Migliaccio et al, 2012; Mitchell et al, 2016). Consistent with these reports, we observed a range of performance on verbal executive function and language tests, with some but not all patients demonstrating deficits relative to the normative population specifically in working memory, lexical-phonological controlled retrieval (e.g., initiation of responses, letter fluency), and lexical-semantic retrieval (e.g., naming, category fluency, conversational word-finding difficulty).…”

“…Consistent with these reports, we observed a range of performance on verbal executive function and language tests, with some but not all patients demonstrating deficits relative to the normative population specifically in working memory, lexical-phonological controlled retrieval (e.g., initiation of responses, letter fluency), and lexical-semantic retrieval (e.g., naming, category fluency, conversational word-finding difficulty). Indeed, a “logopenic syndrome” has been described in PCA patients, and characterized by anomia, verbal fluency impairment, slowed speech rate, and length-dependent auditory-verbal working memory deficits (Crutch et al, 2013; Magnin et al, 2013; Mitchell et al, 2016). As hypothesized, these executive deficits in working memory and lexical retrieval were strongly related to impairments in verbal encoding and delayed recall, but not related to recognition memory.…”

“…Posterior cortical atrophy (PCA) is a focal neurodegenerative syndrome that primarily affects the parietal cortex, with or without involvement of occipital or posterior temporal cortex. Although PCA may infrequently arise due to non-Alzheimer’s disease (AD) pathologies (Mitchell et al, 2016), it is more commonly thought of as an atypical or “visual variant” of AD (Borruat, 2013; Kaeser, Ghika, & Borruat, 2015; Levine, Lee, & Fisher, 1993). Patients with PCA typically present with early visual/spatial dysfunction due to neurodegeneration in these posterior cortical regions, and exhibit a variety of visual and non-visual signs referable to posterior cortices including diminished ability to identify or reach for objects, deficits in numeracy, literacy, and praxis, and other elements of Balint’s and Gerstmann’s syndromes as initially described by Benson and colleagues (Benson, Davis, & Snyder, 1988).…”

“…In a single case study of a PCA patient, deficits in autobiographical memory were reported, and thought to be associated with hypoperfusion in the precuneus and parahippocampal gyrus (Gardini et al, 2011). Deficits in episodic memory were recently linked with atrophy and tau deposition in the lateral parietal cortex in some PCA patients (Bejanin et al, 2017), while executive function deficits specific to controlled lexical retrieval processes (e.g., verbal fluency tasks) and/or length-dependent auditory-verbal working memory (e.g., reverse digit span tasks) have also been described in the literature (Crutch, Lehmann, Warren, & Rohrer, 2013; Magnin et al, 2013; Mitchell et al, 2016). Consistent with these findings in PCA, studies of other posterior cortical lesion patients have also suggested involvement of posterior parietal and temporal regions in executive functions of working memory (Berryhill & Olson, 2008; Koenigs, Barbey, Postle, & Grafman, 2009) and verbal fluency (Abraham, Beudt, Ott, & Yves von Cramon, 2012).…”

Alexia Without Agraphia: A Rare Entity

“…Alexia without agraphia is a neuro-ophthalmologic condition in which the patient loses the ability to read; however, the ability to write is grossly intact. The rarity of this condition is justified by the fact that it is an indirect involvement of an angular gyrus in the dominant hemisphere which represents an area for word recognition, affecting the reading capacity only contrary to reading and writing ability impairment occurring together [4]. …”