Right temporal variant frontotemporal dementia with motor neuron disease

Abstract

Patterns of atrophy in frontotemporal dementia (FTD) correlate with the clinical subtypes of behavioral variant FTD (bvFTD), semantic dementia, progressive non-fluent aphasia (PNFA) and FTD with motor neuron disease (FTD-MND). Right temporal variant FTD is associated with behavioral dyscontrol and semantic impairment, with tau abnormalities more common in right temporal bvFTD and TDP-43 accumulation in right temporal semantic dementia. However, no clinical and anatomical correlation has been described for patients with predominant right temporal atrophy and FTD-MND. Therefore, we performed a database screen for all patients diagnosed with FTD-MND at Mayo Clinic and reviewed their MRI scans to identify those with striking, dominant, right temporal lobe atrophy. For cases with volumetric MRI we performed voxel based morphometry and for those with brain tissue we performed pathological examination. Of three such patients identified, each patient had different presenting behavioral and/or aphasic characteristics. MRI, including DTI sequence in one patient, and FDG PET scan, revealed striking and dominant right temporal lobe atrophy, right corticospinal tract degeneration, and right temporal hypometabolism. Archived brain tissue was available in 2 patients; both demonstrating TDP-43 type 3 pathology (Mackenzie scheme) with predominant neuronal cytoplasmic inclusions. In one case, neurofibrillary tangles (Braak V) and neuritic plaques were also present in keeping with a diagnosis of Alzheimer's disease. There appears to be an association between FTD-MND and severe right temporal lobe atrophy. Until further characterization of such cases are determined, they may be best classified as right temporal variant FTD-MND.

Temporal Variant Frontotemporal Dementia Is Associated with Globular Glial Tauopathy

“…In 2012 , Coon et al described a further subtype of right temporal variant FTD in patients who had associated motor neuron disease. However, all of these patients had FTLD-TDP Type B pathology ( Mackenzie et al, 2011 ).…”

The clinical spectrum of sporadic and familial forms of frontotemporal dementia

“…Similar to the bvFTD/MND spectrum, there are also patients with PPA that develop MND or clinical features suggestive of MND, but not fully meeting criteria, for example, mild wasting or fasciculations were seen in a small proportion of patients with nfvPPA in one study (Burrell et al 2011). Although most cases of PPA-MND have nfvPPA; there is a subgroup of patients with RTLA who can rarely develop MND, typically associated with FTLD-TDP type B pathology and predominant lower motor neuron features (Coon et al 2012), or prominent upper motor neuron signs and pathological evidence of corticospinal tract degeneration and FTLD-TDP type C pathology (Josephs et al 2013). MND in typical svPPA and lvPPA is rare.…”

“…Although most cases of PPA‐MND have nfvPPA; there is a subgroup of patients with RTLA who can rarely develop MND, typically associated with FTLD‐TDP type B pathology and predominant lower motor neuron features (Coon et al . ), or prominent upper motor neuron signs and pathological evidence of corticospinal tract degeneration and FTLD‐TDP type C pathology (Josephs et al . ).…”

Clinical utility of FDG-PET in amyotrophic lateral sclerosis and Huntington’s disease

“…Among the 74 papers identified and screened, 16 were sent to the methodology group for data extraction and assessment (see Figure 1 - PICO 17). Eight papers were excluded for the following reasons: four papers [4][5][6][7] did not have the minimum sample size; two studies used a different index test (Oxygen-15 PET) [8,9]; Chiò et al, (2010) [10] is a case report study; and Carluer at al., (2015) [11] aimed to investigate the neural substrate of theory of mind deficits in ALS patients.…”

“…progression, and is supported by neurophysiological testing. Several FDG-PET studies in small samples of FTD patients with motor neuron disease and further investigations in larger ALS cohorts have shown significant differences of metabolism relative to healthy controls [4][5][6][7][14][15][16][17][18][19].…”