Brain stem, abnormalities

Functional neuroimaging studies suggest that frontal and occipital brain areas are integral to the anxiety response. Patients with panic disorder may have abnormal activation of the parahippocampal region and prefrontal cortex at rest. Panic anxiety is associated with activation of brain stem and basal ganglia regions. GAD patients have an abnormal increase in cortical... 

These are believed to be associated with brain stem injury. Abnormal EEGs generally returned to normal within a period of 0.5-1 month after removal of the worker from exposure (Hoogendam et al. 1965). 

Several types of abnormal movement are recognized. Tremor consists of a rhythmic oscillatory movement around a joint and is best characterized by its relation to activity. Tremor at rest is characteristic of parkinsonism, when it is often associated with rigidity and an impairment of voluntary activity. Tremor may occur during maintenance of sustained posture (postural tremor) or during movement (intention tremor). A conspicuous postural tremor is the cardinal feature of benign essential or familial tremor. Intention tremor occurs in patients with a lesion of the brain stem or cerebellum, especially when the superior cerebellar peduncle is involved it may also occur as a manifestation of toxicity from alcohol or certain other drugs. 

Lindstrom L, Klockhoff I, Svedberg A, Bergstrom K. 1987. Abnormal auditory brain-stem responses in hallucinating schizophrenic patients. Br J Psychiatry 151 9-14. 

Three cases of toxic and progressive spongiform leukoencephalopathy have also been reported as a result of vapor inhalation of heroin (21). There were generalized white matter abnormalities and pathology in the cerebellum, internal capsule, corpus callosum, and brain stem. 

Neurophysiological evaluation of 40 patients with beta-thalassemia major showed abnormal findings in brain-stem-evoked potentials auditory (25%), visual (15%), and somatosensory (7.5%) some had abnormal nerve conduction velocity (25%) and 15% had involvement of multiple neural pathways (39). Subclinical involvement of the auditory pathway was statistically associated with a higher mean daily dose of deferoxamine and a longer duration of treatment. Abnormalities of the somatosensory pathways were related to old age, a long duration of deferoxamine use, and low serum copper concentrations. Multiple neural pathway involvement was related to the duration of treatment. However, deferoxamine is only partly responsible for the subclinical abnormalities of neural pathways often found in patients with beta-thalassemia major. 

Epileptiform convulsions and abnormal electroencep-halographic patterns have been found in studies of insecticide manufacturing workers suffering from intoxication by isodrin. Fourteen patients with convulsions caused by the insecticide all showed specific anomalies in the electroencephalogram, consisting of bilateral synchronous theta wave activity and occasional bilateral synchronous spike and wave complexes believed to be associated with brain stem injury. 

The earliest of these developmental abnormalities involve the brain stem. In a unique case, Rodier et al. (1996) reported the nearly complete absence of the superior olive and facial nerve nucleus, with shortening of the brain stem between facial nerve nucleus and the trapezoid body. They concluded that the initiating injury in this autistic brain occurred around the time of neural tube closure, which occurs at about 4 weeks of fetal development (O Rahilly and Muller, 1994). This timing also corresponds to an increased incidence of autism following exposure to the drug thalidomide during pregnancy (Rodier and Hyman, 1998 Miller et al., 2005). 

In an analysis of six autism spectrum disorder (ASD) brains, Bailey et al. (1998) noted additional abnormalities in the brain stem. These included an unusually large arcuate nucleus in one brain and ectopic neurons on the lateral surface of the medulla in four brains. All the nine brains studied by Bauman and Kemper (2005) have shown abnormal superficial clustering of neurons in the inferior olive and in one brain there was an ectopic superficial cluster of neurons adjacent to the inferior... 

No one is sure why this happens. It might start in a hiccup center in the brain stem by abnormal stimulation of nerves that control the diaphragm and the glottis. 

Cerebral, cerebellar, brain stem white matter abnormalities... 

Suzuki K, Wakayama Y, Takada H, et al [A case of chronic toluene intoxication with abnormal MRI findings abnormal intensity areas in cerebral white matter, basal ganglia, internal capsule, brain stem and middle cerebellar peduncle] (English abstract). Rinsho Shinkeigaku 32 84-87,1992 Tarsh MJ Schizophreniform psychosis caused by sniffing toluene. Journal of Social and Occupational Medicine 29 131-133, 1979 Uitti RJ, Snow BJ, Shinotoh H, et al Parkinsonism induced by solvent abuse. Ann Neurol 35 616-619, 1994... 

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