Clinico-Pathological Correlations of the Frontal Lobe Syndrome: Results of a Large Brain Bank Study

Neuropsychological profile of a patient with multiple sclerosis and psychiatric symptoms that masked and delayed the diagnosis. A case report using teleneuropsychology

Objective: Multiple sclerosis (MS) may include not only severe neurological signs and symptoms, but also cognitive and psychiatric disturbances. When psychiatric symptoms precede or are comorbid with MS, it poses a clinical challenge, because it may lead to a mistaken diagnosis of MS as a psychiatric disorder, delaying proper treatment. We describe the neuropsychological profile of a female patient with MS whose diagnosis was delayed due to neuropsychiatric symptoms. Method: A comprehensive analysis of the medical history and the results of a teleneuropsychological assessment of a 36-year-old Mexican woman with a diagnosis of relapsing--remitting MS (RRMS) was performed. Results: The patient indicates a long history of psychotic, anxious, and depressive features years before the first neurological symptom that led to MS going unnoticed for several years. Language, attentional, perceptual, motor, and learning skills were found to be preserved. Short-term memory and spatial orientation problems were identified, with decreased processing speed and executive dysfunction, including working memory and planning deficits. Conclusions: The patient has a non-typical presentation of neuropsychological alterations with cognitive and behavioral symptoms that resemble dorsolateral frontal lobe syndrome. This case study highlights the importance of considering MS in differential diagnosis of patients with psychiatric symptoms, even in the absence of obvious neurological signs.

Frontal hypometabolism in neurocognitive disorder with behavioral disturbance

Criteria for the behavioral variant of frontotemporal dementia (bvFTD) include decreased frontal metabolism. FDG-PET was used to investigate whether patients with neurocognitive disorder and behavioral disturbance (bvNCD) who did not fulfill three bvFTD criteria had characteristic brain metabolic pattern. Methods: Patients were referred from memory clinic to nuclear medicine for differential diagnosis of NCD with dysexecutive syndrome and predominant mild frontal atrophy. Patients were classified into two groups before FDG-PET, probable bvFTD (n = 25) or bvNCD (n = 27) when only two bvFTD criteria were met. Results: Voxel-based and multivariate PLS analyses of FDG-PET did not show significant between-group difference at inclusion. After 4.8 years of follow-up, most patients with probable bvFTD received the same diagnosis, 3 remained very stable and one participant was given a psychiatric diagnosis. Five patients with bvNCD fulfilled criteria for probable bvFTD at 4.4 years mean follow up, while 2 participants remained very stable and 3 received alternative neurological or psychiatric diagnoses. When initial FDG-PET were compared between groups stratified at follow up (26 bvFTD versus 17 bvNCD), there was a trend (p<.001uncorrected) for lower prefrontal with relatively preserved premotor metabolism in bvFTD compared to bvNCD. Twelve bvNCD participants had neuropsychological testing before inclusion. They all presented executive dysfunction and normal visuospatial performance, and most (n = 9) had memory encoding impairment. Conclusion: Frontal hypometabolism was observed in a dysexecutive presentation of frontal neurodegenerative disorder (bvNCD) that did not fulfill all clinical criteria for bvFTD.

Impact of Imaging and Cerebrospinal Fluid Biomarkers on Behavioral Variant Frontotemporal Dementia Diagnosis within a Late-Onset Frontal Lobe Syndrome Cohort

BACKGROUND

The criteria for behavioral variant frontotemporal dementia (bvFTD) incorporate MRI and [18F]-FDG-PET. Cerebrospinal fluid (CSF) analysis is merely advised for excluding Alzheimer's disease.

AIMS

We aimed to assess the impact of biomarkers on diagnostic certainty and contingent changes of bvFTD diagnosis within the clinically relevant neuropsychiatric differential diagnosis of subjects with a late-onset frontal lobe syndrome (LOF).

METHODS

We included 137 patients with LOF, aged 45-75 years, 72% males. Biomarker disclosure was considered contributing after any substantial difference in diagnostic certainty or a diagnostic change. Percentages of contributing biomarkers were compared between three major diagnostic groups (bvFTD, psychiatry, other neurological disorders). Certainty levels in stable diagnostic groups were compared to those with a diagnostic change.

RESULTS

Biomarkers contributed in 53, 60 and 41% of the LOF patients for MRI, [18F]-FDG-PET and CSF, respectively. Biomarkers changed the diagnosis in 14% of cases towards bvFTD and in 13% from bvFTD into an alternative. Those that changed had a lower level of a priori diagnostic certainty compared to stable diagnoses.

CONCLUSION

Our study not only supports the widely accepted use of MRI and [18F]-FDG-PET in diagnosing or excluding bvFTD, but also shows that CSF biomarkers aid clinicians in the diagnostic process.