Cardinal signs of Parkinsons disease

What are the cardinal signs of Parkinsons disease? 

Tremor, bradykinesia, rigidity, and impairment in postural reflexes are the four cardinal signs of PD. 

Tremor at rest is one of the most typical signs of parkinsonism. It is characterized by an oscillatory pronation–supination at a 3- to 5-Hz frequency.

In addition to the hands, where it assumes an appearance of pill rolling, this type of tremor is commonly observed in the facial musculature (lips and chin) as well as in the legs.

Head tremor, however, is rare in parkinsonism, and its presence should suggest the diagnosis of essential tremor (ET).

The term bradykinesia is used to describe slowness of movements that often causes difficulties for the patients in getting dressed, feeding, and maintaining personal hygiene.

Bradykinesia is evident when a patient performs rapid alternating movements, such as pronation and supination of the forearms. 

Rigidity , often associated with the cogwheel phenomenon, is another hallmark of parkinsonism. 

Impairment of the postural reflexes is responsible for the falls that are frequently experienced by parkinsonian patients.

Parkinsonian gait often reflects a combination of bradykinesia, rigidity, and postural instability. 

Sources

• Gerfen CR: Molecular effects of dopamine on striatal-projection pathways. Trends Neurosci 23(10 Suppl):S64–S70, 2000. 
• DeLong MR, Wichman T: Circuits and circuit disorders of the basal ganglia. Arch Neurol 64: 20-24, 2007. 
• Chase TN, Oh JD: Striatal dopamine- and glutamate-mediated dysregulation in experimental parkinsonism. Trends Neurosci 12(10 Suppl):S86–S91, 2000. 
• Brichta L, Greengard P, Flajolet M: Advances in the pharmacological treatment of Parkinson’s disease: targeting neurotransmitter systems. Trends Neurosci 36(9):543-554, 2013. 
• Zrinzo L, Zrinzo LV, Tisch S, Limousin PD, Yousry TA, Afshar F, et al.: Stereotactic localization of the human pedunculopontine nucleus: atlas-based coordinates and validation of a magnetic resonance imaging protocol for direct localization. Brain 131(Pt 6):1588-1598, 2008. 
• Ellens DJ, Leventhal DK: Review: Electrophysiology of basal ganglia and cortex in models of Parkinson disease. J Parkinsons Dis 3(3):241-254, 2013. 
• Khan ZU, Gutierrez A, Martin R, Peñafiel A, Rivera A, de la Calle A: Dopamine D5 receptors of rat and human brain. Neuroscience 100:689–699, 2000. 
• Bamford NS, Robinson S, Palmiter RD, Joyce JA, Moore C, Meshul CK: Dopamine modulates release from corticostriatal terminals. J Neurosci 24:9541-9552, 2004. 
• Goedert M, Spillantini MG, Del Tredici K, Braak H: 100 years of Lewy pathology. Nat Rev Neurol 9(1):13-24, 2013. 
• Jankovic J: Parkinson’s disease: clinical features and diagnosis. J Neurol Neurosurg Psychiatry 79:368-376, 2008.