METHOD: Electromyographic (EMG) signals of the orbicularis oris superior [OOS], orbicularis oris inferior [OOI] and depressor labii inferioris [DLI] were recorded during syllable production and expressed as polar-phase notations.
RESULT: PD participants exhibited the general features of reciprocity between OOS, OOI and DLI muscles as reflected in the EMG during syllable production. The control group showed significantly higher integrated EMG amplitude ratio in the DLI:OOS muscle pairs than PD participants. No speech rate effects were found in EMG muscle reciprocity and amplitude magnitude across all muscle pairs.
CONCLUSION: Similar patterns of muscle reciprocity in PD and controls suggest that corticomotoneuronal output to the facial nucleus and respective perioral muscles is relatively well-preserved in our cohort of mild idiopathic PD participants. Reduction of EMG amplitude ratio among PD participants is consistent with the putative reduction in the thalamocortical activation characteristic of this disease which limits motor cortex drive from generating appropriate commands which contributes to bradykinesia and hypokinesia of the orofacial mechanism.
CASE REPORT: An 87-year-old male had a tumour nodule over the left parotid tail for about 20 years. Physical examinations revealed a 4.5 cm soft, non-tender and fixed mass. After the left parotidectomy, pathology confirmed the diagnosis of IDC arising within an intraparotid lymph node. The cystic component of the tumour was lined by single to multilayered ductal cells with micropapillary growth pattern. The solid part showed intraductal proliferation of neoplastic cells in solid, cribriform, micropapillary and Roman bridge-like structure. By immunohistochemistry (IHC), the tumour cells were positive for S-100, CK (AE1/AE3), mammaglobin, SOX10, and estrogen receptor (ER), with myoepithelial cell rimming highlighted by positive p63 and calponin IHC stains. The prognosis of this patient is excellent after complete excision.
DISCUSSION: The mechanism of salivary gland tumour arising in the intra-parotid gland LN was assumed to be related to salivary duct inclusion within the intraparotid gland LN which is a normal occurrence during embryology development. Although the terminology may raise some confusion about the relationship between IDC and conventional salivary duct carcinoma (SDA), they are different in immunophenotype and clinicopathologic features. IDC is characterised by S100 (+) ER (+) with predominant intraductal growth and excellent prognosis; while SDC features S100 (-) androgen receptor (+) with predominant invasive growth and aggressive behavior. Recent discovery of recurrent RET gene rearrangement in IDC but not SDC also supports that IDC is not precursor lesion of the SDC.