A 76-year-old woman with a 2-year history of Parkinson\'s disease presented with dropped head, which had developed rapidly after she had been prescribed donepezil hydrochloride (DNP) at 3 ‍mg/day. After one month of medication, the extent of the head drop reached 90°. Examination revealed hypertrophy of the left sternocleidomastoid muscle, but no weakness of the extensor muscles in the cervical region. Surface electromyography demonstrated co-‍contraction of the sternocleidomastoid and splenius capitus muscles during head flexion and extension. DNP was withdrawn, resulting in immediate amelioration of the head drop, and complete resolution was achieved after two months. Although head drop is often seen in patients with Parkinson\'s disease, few previous reports have documented DNP as a causative factor. If patients with Parkinson\'s disease develop head drop, it is important to investigate any history of DNP medication.

A 64-year-old female developed Parkinson\'s disease at the age of 52 years. She experienced muscle weakness in the upper right extremities and dropped head at 62 and 63 years, respectively; both symptoms were considered to be associated with Parkinson\'s disease (PD). The dosage of L-DOPA was increased from 200 mg/day to 900 mg/day; however, her neurological symptoms did not improve. Eventually, she was diagnosed with amyotrophic lateral sclerosis (ALS) at 64 years. She was placed under palliative care, and died of respiratory failure and malnutrition. Neuropathologic findings were consistent with the coexistence of PD and ALS. In fact, there were α-synuclein immunoreactive Lewy bodies (Braak stage 4) as well as TDP-43 immunoreactive deposits in the motor nuclei at the level of brainstem and spinal cord. Therefore, coexisting pathologies must be taken into account in a patient showing multi-system symptoms.

Dropped head syndrome due to focal myositis is extremely rare. Due to the rarity of the disease, its clinical characteristics and prognosis remain unknown. We present a unique case of dropped head syndrome due to focal myositis that exacerbated following cellulitis and was dramatically improved along with the improvement of her cellulitis only treated with antibiotics. We should consider the possibility of preceding trigger event such as infection when we face with the exacerbation of focal myositis before making a decision of strengthening immunosuppressive therapy to avoid unnecessary increase of glucocorticoid.

Dropped head syndrome can be seen in many neuromuscular diseases. However, there are very few diseases in which neck extensors are weak among neuromuscular diseases. A 7 years old boy who had weakness of the neck extensor muscles, creatinine kinase elevation and dystrophy findings in biopsy followed up with the preliminary diagnosis of muscular dystrophy is presented. We detected p.N456K (c.1368C > A) heterozygote mutation by the gene sequencing in the Lamin A/C assocıated (LMNA) gene. This mutation was previously reported as Emery-Dreifuss muscular dystrophy.