Kent M. Perryman

Posterior Cortical Atrophy: Clinical Characteristics and Differences Compared to Alzheimer’s Disease

Background: Predominant and progressive complex visual disorders are often due to posterior cortical atrophy (PCA), a rare early-onset dementing syndrome presenting with visual complaints. In clinicopathological studies, PCA is most commonly considered a form of Alzheimer’s disease (AD); no prior study has evaluated clinical differences between PCA and AD. Methods: This study identified 15 patients who presented with progressive complex visual disorders and predominant occipitoparietal hypoperfusion on SPECT. These patients were retrospectively compared on clinical variables with 30 patients with clinically probable AD matched for gender, age and duration of illness. Results: The PCA patients presented with alexia, elements of Balint’s syndrome, apperceptive visual agnosia, dressing apraxia and environmental disorientation along with elements of Gerstmann’s syndrome. Compared to the AD patients, the 15 PCA patients (mean age of onset 58 years, range 51–64) had significantly better verbal fluency, less memory difficulty, more depression and greater insight into their illness but similar familial and apolipoprotein E risk factors. In the PCA patients, MRI often showed occipitoparietal atrophy without detectable mesiotemporal atrophy. Conclusions: PCA is a distinct clinical syndrome and not just AD with prominent visual deficits. Compared to AD controls, PCA patients have better language and memory but more insight and depression and more posterior atrophy on MRI. These results indicate clinical criteria for the diagnosis of PCA and recommend specific interventions such as visual aids and antidepressant medications. Similar risk factors and course suggest that PCA is most commonly an early-onset posteriorly shifted AD variant.

Frontotemporal dementia versus Alzheimer's disease: Differential cognitive features

Frontotemporal dementia (FTD) is a common neurodegenerative dementia that can be difficult to distinguish clinically from Alzheimers disease (AD).The differential distribution of pathology in FTD and AD predicts the presence of differential cognitive features on mental status examination. We compared 39 FTD patients with 101 AD patients on the Consortium to Establish a Registry in AD examination supplemented by cognitive areas from the Neurobehavioral Cognitive Status Examination. The FTD patients were diagnosed using noncognitive clinical and neuro-imaging criteria and were comparable to the AD patients in terms of gender, educational level, and dementia severity ratings. The FTD patients performed significantly better than the AD patients on constructions and calculations. These findings were at the lower limits of normal for older normal controls and persisted after covarying for younger age and higher Mini-Mental Status Examination scores in the FTD group. In addition to personality and neuroimaging features, relatively preserved performance of elementary drawings and calculations in FTD suggests additional features for distinguishing FTD patients from comparably demented AD patients. NEUROLOGY 1996;47: 1189-1194

Differences between Alzheimer's disease and vascular dementia on information processing measures.

This study evaluated information processing differences between 30 vascular dementia (VaD) patients, 30 Alzheimers disease (AD) patients, and 30 normal elderly (NE) controls. They were administered a complex reaction time test, a continuous performance test (CPT), and a neuropsychological battery. Compared to NE, both dementia groups had significantly slower motor reaction times and made more errors on the CPT. Compared to AD patients, the VaD patients were slower in stimulus categorization time and had increasing omission errors and persistent commission errors throughout the CPT trial, VaD, which usually includes frontal-subcortical circuit injury, can impair mental speed and stimulus response initiation.

Behavioral Differences Between Frontotemporal Dementia and Alzheimer's Disease: A Comparison on the BEHAVE-AD Rating Scale

Frontotemporal dementia (FTD) is a dementing syndrome characterized by the occurrence of neuropsychiatric features early in the clinical course. Patients with Alzheimers disease (AD) also have neuropsychiatric symptoms, but these symptoms typically emerge later in the course after the development of memory and other cognitive impairment. The BEHAVE-AD, an instrument developed to evaluate neuropsychiatric features in dementia, may help characterize the behavioral features of FTD and differentiate FTD from AD. This study evaluated BEHAVE-AD results of 29 patients with the diagnosis of FTD compared to those of 29 patients with the diagnosis of probable AD of similar dementia severity. The FTD patients had significantly worse global BEHAVE-AD scores compared to the AD patients. Verbal outbursts and inappropriate activity characterized the FTD patients, and three BEHAVE-AD subscales correctly classified 69% of the patients. The assessment of neuropsychiatric symptoms with a standardized scale or inventory can help distinguish dementia patients with FTD and AD.

Compulsive Behaviors as Presenting Symptoms of Frontotemporal Dementia

Frontotemporal dementia (FTD) is a common neurodegenerative dementia syndrome. Compulsive behaviors frequently occur in FTD and may be presenting symptoms of this disorder. This study evaluated compulsive behaviors as presenting symptoms in 29 patients with FTD compared to 48 patients with Alzheimers disease (AD) enrolled in the UCLA Alzheimers Disease Center. The FTD patients met the Lund and Manchester criteria for FTD and had predominant frontal hypoperfusion on single-photon emission computer tomography neuroimaging. The AD patients met National Institute of Neurological and Communicative Disorders-Alzheimers Disease and Related Disorders criteria for clinically probable AD. Compulsive behaviors occurred in 11 FTD patients (38%) versus 5 AD patients (10%) (χ2 = 6.73, P < .01). This difference persisted after controlling for the younger age of the FTD group. There was a range of compulsive behaviors, with the most frequent being repetitive checking activities. Compulsive behaviors are common presenting symptoms among FTD patients and may result from an inability to inhibit urges to perform compulsive movements from damage to frontal-striatal circuits.

Effects of normal aging on the performance of motor-vehicle operational skills

Operational skills involved in controlling a motor vehicle were measured in two groups of very healthy elderly drivers and a young control group to test the hypothesis that there are age-related declines in operational performance that may influence driver safety. An actual behind-the-wheel, standardized road test was employed using a motor vehicle equipped with sensors to record speed, braking activity, and lane position, as well as direction and magnitude of front-wheel and eye-movement excursions. The data from these sensors were used as dependent measures of operational performance. Older drivers made fewer steering and eye-movement excursions and drifted across the center line more frequently than the young control group. Younger drivers drove significantly faster and executed more braking applications than did their older counterparts. The motor-vehicle operational performance of older healthy drivers was related to visual-spatial attentional declines and the useful field of vision associated with the normal aging process.

Disrupted Facial Empathy in Drawings from Artists With Frontotemporal Dementia

The sense of empathy may be altered by brain disease. We report the drawing performance of four artists who developed frontotemporal dementia (FTD). The first three, but not the fourth, had a prominent decrease in empathy for others as well as alterations in their caricatures of people. Their drawings of faces became distorted, menacing, skeleton-like, or ‘alien’. None of the four had facial recognition difficulties, problems in interpreting facial emotions, or a decreased appreciation of the distinction between animate and inanimate objects. Functional brain imaging in the patients revealed bilateral frontal hypometabolism or hypoperfusion, and the three with altered drawings had additional prominent involvement of the right temporal lobe. These FTD patients and the literature suggest that FTD, possibly with greater right temporal involvement, disrupts the sense of empathy from human faces.

Epileptic forced thinking from left frontal lesions

Forced thinking is an incompletely understood and rarely described epileptic aura.We studied three patients with forced thinking from left frontal lesions, two neoplastic and one vascular. All three experienced repetitive, intrusive thoughts at the onset of seizures. Their forced thinking was associated with the desire to vocalize, orobuccal movements, and speech arrest. The episodes occurred with other ictal manifestations and responded to antiseizure therapy. These patients suggest that epileptic forced thinking is a heterogeneous phenomenon; forced thinking from left frontal lesions is a manifestation of expressive language and is distinct from experiential thoughts arising from temporal limbic foci. NEUROLOGY 1996;47: 79-83

Delayed matching-to-sample performance during a double-blind trial of tacrine (THA) and lecithin in patients with alzheimer's disease

During a double blind, inpatient-outpatient study of THA (tacrine) and lecithin in Alzheimers disease, data on a laboratory-based delayed-matching-to-sample (DMS) test was collected on six of 10 subjects. DMS measures proved more sensitive to drug effects than clinical measures of cognitive performance. Both clinical and DMS measures suggest that patients with mild to moderate impairment are more likely to show modest improvement in performance than advanced cases. Outcome measures are related to possible mechanisms of attention and memory.

Procaine-induced seizures in epileptic monkeys with bilateral hippocampal foci☆

Intravenous procaine HCl given at low doses (0.5-2.5 mg/kg) to two monkeys with bilateral alumina hippocampal foci depressed interictal spiking or had little effect. At 5.0 mg/kg unilateral limbic activation occurred. At 10.0 mg/kg unilateral or bilateral limbic activation and generalized seizures could be evoked within 3-10 min. At higher doses (15 and 20 mg/kg) bilateral limbic activation or brief (one min) generalized seizures occurred. The unilateral-onset psychomotor seizures were not identical to spontaneous psychomotor seizures, and the generalized seizures never occurred spontaneously in these monkeys. However, these results do indicate that procaine challenges may selectively activate limbic epileptogenic areas without activation of debilitating generalized tonic-clonic seizures.